ML20065N951
| ML20065N951 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 11/30/1990 |
| From: | Browne S CAROLINA POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20065N942 | List: |
| References | |
| 90-05, 90-5, NUDOCS 9012130027 | |
| Download: ML20065N951 (72) | |
Text
_ - _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _
File No. 13011L Carolina Power & Light Health Physics & Chemistry Section Dosimetry Technical Report: 90-05 Brunswick TIP Incident Dose Calculations November 30, 1990 Prepared By: -
0(4Jr12 Approved By: ,/ ,
/
9012130027 901207 PDR ADOCK 05000324 Q PDC
Brunswick TIP Incident Dose Calculations Introduction on July 5, 1990, Mr. Larry Dew was involved in a radiological incident which resulted in an unplanned exposure to his left hand while working on a job to install new transient in-core probes (TIPS) at the Brunswick Nuclear Flant. E&RC Experience Report Number 90-004 contains a complete description of the occurrence, its cause, and corrective actions. Since no monitoring devices were worn on the hand, it was necessary to calculate the dose based on the best information available, primarily obtained from interviews, records, and drawings. Originally, a W al exposure to the hand of 10.6 rem was estimated by CP&L. HJwever, Mr. Dew disagreed with the assumptions used and refused to sign the final Personnel Exposure Investigation report containing this dose.
Subsequently, Mr. Dew filed a complaint with the Department of Labor which questioned the validity of the dose. As a result of the DOL allegations, the NRC requested additional information supporting the dose assignment. In response, CP&L reexamined the assumptions and methodology used in the dose calculations and concluded that the original exposure estimate was valid. This report summarizes the methodology and results of dose calculations.
General Assumptions The shallow dose to the hand ('/ mg/cm2 tissue depth) represents the most limiting exposure case for the TIP incident. Since the exposed worker wore two pairs of rubber gloves, the dose was determined for both beta and gamma radiation at a depth of 99 mg/cm 2 , which is the sum of the density thickness of the gloves and skin (See Attachment 1).
The dose calculatior.s are based or, two principal nuclides, Mn-56 and Al-28, which represented 95.6% of the total activity in the detector and 98.6% of the activity in the cable (see Attachment 2) .
The dose contribution other nuclides is small and is more than offset by conservative assumptions employed in the dose calculation.
The dose from the incident is calculated separately for exposure from the detector versus tne drive cable because of differences in geometries, activities, and exposure times.
Many assumptions were made in performing the dose calculations, but the most critical ones concerned the length of time the TIP was in the core and the length of time different parts were touched.
These times were determined based on interviews with participants in the incident and on reenactments, all of which are described more completely in Attachment 10. Because the actual times are 2
unknown, upper and lower' bound doses were calculated, in addititm to_a.best estimate dose, in order - to give an indication of the '
degree ' of uncertainty. The table below summarizes the time assumptions used in the dose calculations.
Lower Best Upper Bound Estimate Boilnd Time in Core 120 sec 180 sec 300 sec Time Touching 0 0 .5 sec "
TIP Time 7 auching 3 sec 4 sec 4 sec Cable
~
In addition to the above assumptions, the primary data used in the dose calculations were design information for the TIP (detector and cable materials and dimensions) and neutron activation analyses for
.various irradiation and decay times, both provided by Router-Stokes, Inc., the- TIP manufacturer. Attachment 3 contains drawings and diagrams representing the detector and cable and
-Attachment 4 contains the results of neutron activation calculations.
Gamma Dose Calcul.htions The gamma dose was calculated using the computer code Microshield, a-program.for analyzing gamma radiation shielding-(Ref. 4).. The program input includes: geometry, source nuclides and activities, source and shield materials, dimensions of source and shields, and position at which dose rate' is to be determined. The output is the dose ~ rate at the specified point.
The . basic- geometry selected ' to model .both the detector and the cable was - a cylindrical source (side ' view) _ surrounded by cylindrical shields. For this geometry, Microshield calculates the exposure rate at a specified point using a point-kernel numerical-Lintegration' technique. Three integration parameters determine how finely the source volume is divided for the numerical integration:
radial, horizontal angle, and vertical angle. A value of 11 was 3
selected, thus dividing the. source into 11 differential volumes 2 The dose - for . complex geometries can be approximated by breaking them into several simple geometries for- which the dose can be calculated ~ separately and then summed. In this case, the total gamma dose -is the sum of three separate geometry and nuclide com'oinations.
3
- _ . . . .~ - _ - .-~ _-~ .
- 1. Cable Containino Mn-56 The. gamma dose from the cable was calculated only for Mn-56, .since the activity of Al-28 was negligible. the activity was assumed to be uniformly distributed in a solid, cylindrical volume of iron, 18 inches 2.ong.
Because of the small' distance between the hand anc the cable, the percent contribution to the dose from parts of the cable greater than 9 inches away is negligible.
Attachment 5 shows the Microshield results.
- 2. TIP Insulators Containina Al-28 The Al-28 is contained in alumina (A102 3) insulators inside the outer detector shell. The activity was assumed to be uniformly distributed in a solid, cylindrical volume representing the alumina surrounded by an iron- shield representing the detector shell.
Attachment 6 shows the Microshield results.
- 3. TIP Detector Shell Containina Mn-56 The Mn-56 is contained primarily in the stainless steel -
detector shell. The activity was assumed to be uniformly distributed in a hollow cylindrical-volume representing the stainless steel shell. The dose from a hollow cylinder was obtained by calculating the dose from two solid cylinders of different diameters and subtracting the smaller .from the . larger. In this case, the aiameters used were the inside and outside diameters of the-detector shell. Attachment 7 shows the Microshield results.
The calculations for 120 second TIP irradiation times were done
-with Microshield and were adjusted asing a spreadsheet program for-different--irradiation and exposure times. Attachment 8 contains s
' summary of the gamma dose. calculations for each of the above three
. cases based on upper bound, lower bound and best estimate
' assumptions.
Beta Dose Calculations The beta dose was calculated using equations which integrate =the
. experimentally derived beta' particle point source dose distribution function for several simple geometries (Ref. 2). The total beta dose is the sum of the beta dose for three different geometries and nuclide combinations:
1.- Infinite, Plane' Slab of Infinite Thickness This geometry was assumed for the. beta dose from Mn-56 in the cable. This is considered to be a reasonable, probably conservative, approximation for a hand wrapped around a long, cylindrical ~ source (the cable) whose L 4
w .
. radius- exceeds the maxiinum beta particle range.: Tm dose. at a , depth x outside an infinite, plane slab of 1 infinite thickness is 'given by the. following. equation ,
I (Ref 2, p.722, Eq. 24): .
1
'D.(x) = . 5Don ( c2 [ 3_e(1 vrici-vx/c (2+1n (c/vx) ) )+e(l'"*)) , rad i
( ) m 0 for x 2 c/v Where: Do = 2.13 Ent , rad /hr En = Average beta energy, - MeV r = Activity concentration, pCi/g a = [ 3c2 -(c a_1),) 1 2 0.17 <Eo< 0. 5 c = 1.5. 0. 55Eo<1. 5 1 1. 55Eo<3 -
V = 18.6/(Eoa.036)3*", cm2 jg Eo = Maximum beta energy, MeV L x = Depth in absorber outside slab, g/cm2
- 2. Infinite. Plane Slab of Finite Thickness This geometry was assumed for calculating the beta dose'-
from Mn-56 in the outer detector shell of the TIP. It was chosen ~ because the thickness of the detector shel) is less than the maximum beta particle range. The dose at a _ point outside a infinite,. plane slab- of ' finite thickness is given by the following equation (Ref 2, p.725, Eq. 27):
D(x,h) = D(x,m)-D(x+h,m)
The terms on the right are given by equation'24.
- 3. -Schere Containina Uniform 1v Distributed Activit,y This geometry was assumed for Al-28' beta dose calculation .
from the ~ alumina insulators .inside the outer shell of the detectors. - The dose,at a distance x from the center-of a sphere _.of radius.b is-given byTthe.following equation-(Ref. 2, p.736, Eq. _ -3 8) :
D,p3(x, b) = . SoDo[ (vb+1) e**+ (vb-1) ed) ell'"")/vx E For: x 2 c/v+b Attachment 9 contains a summary of the beta dose calculations-for each of the three geometries' based on upper bound, lower bound and.
-best estimate assumptions.
The dose contribution from bremsstrahlung radiation was considered 1 negligible.- The ratio, r, of energy loss from bremsstrahlung to -
that from collisions can be estimated by the-following equation
'(Ref. 6, p. 175):
5 L
5 .
. . - ~ . . . . . . - . - . - _ , - . - ~.. - _~ - . - - - . - - - - - . - _ . - . . - - - . .
.g e l
l r = (T2/700)
Where:- T = beta particle energy ..
Z = atomic number of absorber Assuming T equals the average . energy of Mn-56 (.86 MeV) and Z-equals the atomic number of iron (26), then r equals 3.1%. Since the bremsstrahlung radiation will deposit its energy over a range-of absorber thickness, the dose contribution at the skin depth will be only a very small fraction of the 3.1%.
U Total Dose The total shallow dose to the hand from the TIP incident is simply the sun of the beta and gamma doses as summarized in the following table.
Beta Dose Gamma Dose Total Dose (rad) (rem) (rem)
Lower Bound 4.623 0.698 5.321 L Dest Estimate 9.228 1.392 10.620 Upper Bound 36.385 7.687 44.072 l
conservatisms A number of conservative assumptions.and approximations were used in performing the dose calculations. Several of those .are disc ussed below, including estimates of the magnitude of the effect onllose calculations for some.
Neutron Flux Reuter-Stokes used a flux _ of 5.0 x 10 13 n/cm2 /sec in . the neutron activation calculations. It was later determined that the. average neutron flux.in the channel traversed by.the TIP during the -incident was 4.394 x 10 13 n/cm2 /sec. This difference translates directly into a 14% conservatism in the calculated dose.
Skin Deoth
.NRC regulations requirc that the dose to the extremities be reported =at a depth of 7 mg/cm 2, but.the average epidermal-
- thickness on palms of the hands is 'about 40 mg/cm2 (Ref. 5, p.50). The beta. dose at 40 mg/cm2 . is 18% less than -- at 7 mg/cm2 ,
l 6
.. - - . ~ -- -
Geometry In most cases the geometry was selected in a conservative manner. For example, the use of an infinite, plane slab for beta dose calculations will slightly.over estimate the beta dose compared to a cylindrical geometry.
Electronic Eauilibrium For all gamma dose calculations electronic equilibrium was assumed to exist at the 7 mg/cm depth. 2 For high energy photons equilibrium will not be established at this depth, which will result in an over estimate of the gamma dose.
Decav Time The decay time is the amount of time required to crank the TIP from the core to the TIP box. After leaving the core, the TIP must travel approximately 60 feet to reach the TIP box. At a normal speed of 1 foot per second, this would take about 60 seconds, however, during the incident the crank was difficult to turn and the speed was probably slower. Nevertheless, a decay time of only 30 seconds was assumed in the dose calculations, so that the activity assumed for the dose calculations is probably conservatively high. The effect is small for Mn-56 which has a half-life of 2.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, but is significant for Al-28 which has a half-life of 2.24 minutes.
Independent Evaluation of Dose Calculations Mr. Robert E. Alexander, a health physics consultant, was engaged by CP&L to perform an independent evaluation of the dose calculations for this incident. His report, reproduced in Attachment 11, confirms the validity and conservatism of the CP&L dose calculations. The beta dose, which is the largest component, was recalculated using a Monte Carlo simulation code by Dr.-Thomas R. Mackie of the University of Wisconsin. Tha results are in excellent agreenent (within 7 percent) with the CP&L dose calculation performed using equations publishad by Hine and Brownell in Fadiation Dosimetry.
Conclusion The original estimate of the dose to the lef t hand of Mr. Larry Dew was 10.6 rom. After a thorough reexamination of all assumptions and calculation methods, this is still considered to be a valid and probably conservative estimate of the dose received during the TIP incident.. Therefore, no changes are recommended to the previously assigned dose to Mr. Dew.
7
References
- 1. Radiation Health Handbook, U.S. Department .of Health, Education, and Welfare, Public Health Service, January 1970.
- 2. Radiation Dosimetry, G. J. Hine and G. L. Brownell, Eds.,
Academic Press, New York, 1956, Chapter 16.
-3. Principles of Radiation Protection, K. A. Morgan and J. E.
Turner, Eds., John Wiley & Sons, New York, 1967, Chapter 8.
- 4. Microshield 3 Manual, Grove Engineering, Inc., Washington Grove, MD, 1988.
- 5. ICRP Publication 23: Report of the Task Group on Reference MAD, Committee 2 of the ICRP, Pergamon Press, New York, 1975.
- 6. Radiation Dosimetry, 2nd Edition. Volume I: Fundamentals, F.
H. Attix and W. C. Roesch, Eds., Academic Press, New York, 1968.
I 1
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Attachnent 1 Depth at Which Dose calculated The dose was calculated at a depth equivalent to the thickness of two pairs of rubber gloves plus the thickness of skin. The glove thickness was determined by weighing a sample of glove material of known area.
Glove sample area = 25 cm2 Glove sample weight = 1.15 g Single glove thickness = .046 g/cm2 Double glove thickness = .092 g/cm2 Skin thickness = .007 g/cm 2 Total depth = .092 + .007 = .099 g/cm; t
Attachment 2 Principal Nuclide Decay and' Emission Data L
l l
t l-
Al-JoS Atomic number : 13 Atomic weight : 28 Half life : 2.24 minutes
====== Betas: ======
probability maximum average per decay (MEV) (MEV) 1 1.000000 2.864200 1.242300
= Gammas & X-rays: =
probability energy per decay (MEV) 1 1.000000 1.778900 Mn-56
=
Atomic number : 25 Atomic weight : 56 Half life : 2.5785 hours0.067 days <br />1.607 hours <br />0.00957 weeks <br />0.0022 months <br />
====== Botas: ======
probability maximum average per decay (MEV) (MEV) 1 .011600 .325630 .099100
- 2 .146000 .735530 .255200 l 3 .278000 1.037900 .381900 4 .562000 2.848600 1.216700 5 .001189 .987800 .373140
= Gammas & X-rays: =
l probability energy i per decay (MEV) 1 .988700 .846750 2 .271890 1.810700 3 .143360 2.113100 4 .009887 2.522900 5 .006525 2.657500 l 6 .003065 2.959800 7 .001681 3.369600 8 .001626 1.351400
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Attachment 4 Neutron Activation Calculations i
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._.._4 _5 e -t i HEUTRON ACTluATI;N 'u.T..T:oN 07/17/*0 GaMya ?!r 'ABLE og:te Ag
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4 AAFENT l DAUGWfEA ACTIVITY '
!RRAdlATION i ". i v n+ n : v ess ;; o::;e ;sr es ,'?M:pe 'wries *ON0!f!ONS 4 .......................................................................
N3 0.00 ; Ma24 0.09'O l F+59 0.000 l Flue: 5.0E+13 i.17 Mgi7 0.040 '
CoSQ 0.000 ;-tme: 9 0-e Mg ,
i At 0.00 ; Al23 0.007 : Co60 0.000 l
,3 Ti 0.00 : ic46
.000 , N357 0.000 lMooerator Temo sc47 4', .000 ; Ni65 0.000 l(Deg C): 285
- 1 Cr 3.6C l 12 Mn 3 . 0 9 -g 9 : 4 8 0.000 : Cu64 0.000 :
- r, 261.00 ;; TiAS '.000
- Cu66 0.000 lFest Fl u x 0.05
- r TiB1 .000 l Mos3 0.000 lFacter: 0.8
.: Co I 0.003 : Mo99 0.000 l
- s ai 0.00 lI Cr51 0.000 l Cooling Down
'i Cu 0.50 ; #, Mn64 0.000 l MetOi 30'
' Time:
1; Mo 0.00 l 5.241 l Te182 K.312N, Mode:
Ta 0.00 : TOTAL; -
5 e 8
...,..........................................'tv-<'..................
19 20 DECAY OF ACTIVITY , , _ . . ._g OnLine CapsNum 17-Jul-90 09:18 AM S
- 17: 60 4- 9 C-0 E F-----G H I J K c
1 NEUTRON ACTIVATION CALOULATION 07/17/90
$ AMPLE NAME: GAHMA T!P CABLE 09:19 AM 2
3 .......................................................................
A PARENT l OAUGHTER ACTIVITY l IRRA0!ATION Element Mass l Isotope Curies l1sotope -Curies : CONDIT10N$
5 6 ---------------+------ -----------+------------------+-----------------
Na- 0.00 l Na24 0.000 l Fe59 0.000 l F l u x :- 5.0E+13
.7 Mg27 0.058 Co69 0.000 l Time: 180 6 Mg 5.17 l 9 A1 0.00 l A128 0.006 l Co60 0.000 l Ti- 0.00 i So46 0.000 ' Ni57 0.000 ' Mode ra t or Temp -
10-11 Cr t.60 l So47 0.000 l Ni65 0.000 l(0 9 c): 285 Mn 3.08 l Sc48 0.000 l CuG4 0.000 l 12.
13 .Fe 261.00 l Tt45 0.000 l Cu66 0.000 l Fast ritx Co 0.05 l TiB1 0.000 l Mo93 0.000 l Factor: 0.9 14 15 Ni 0.00 l Cr51 0.003 l MoS9- 0.000 l Mn54 0.000-l Mo101 0.000 l Cooling Down 16 Cu 0.00 l 5.229 l Te192 0.000 l Time: 60 17 Mo 0.00 1 Mn56 c
18 Ta 0.00 TOTAL: 5.297 l Mode:
33 .......................................................................
DECAY OF ACTIVITY 20 4 b.
09:19 AM OnLine . CapsNum .,.
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- T!t4TiaN .AL;ULATION 07/17/?O i 2 ; AMPLE NAME: 09:03 AM l 3 ........-..............-.....---......-..-.......---.......--..........
I 4 PARENT l DAUGHT~E ACTIVI'f i IRAA0!ATION
> Eie-ent Mass ll tece Cur 3-s ;!sctope Ouries l CONol!!ONS- --
- .......-....-...,-.....--..---.-.....--- ----....---..+................. <
7 u 0.00 , Ne24 J.000 ' e59 0.000 'rlax: 5.0t+13 s Mg 0.01 l Me27 9.0^0 . Co!3 0.000 l*tm.: 180
-s Al 0.4A y 1.017 l f.o60 0.000 :
- 0 Ti 0.65 ; ac46 v.000 ; NiS7 0.000
- Moserstor Temp 11 Cr 0.93 : Sc47 0,000 l Ni65 0.001 l(Deg C): 285-12 Mn o.;0 ; se as 0.000 ; Cv64 0.001 l
- ) Fe 3.51 l T145 G,000 l Ca66 0.038 ; Fast Flux 0.015 ; Mo93 14 Ce 0.05 ; tis 1 0.000 lFector
- -( 0.0 15 Ni 0.47 l Cr51 0.000 : Moss 0.000 l 14 Ca 'O.02 , Mn54 0.000 l Mo101 0.000 l Cooling Down 17- Mo 0.00 l Mn56 c.169 l Ta192 0^ l Time:. 30 18 Ta 0.00 ; TOTAL: .241 Mode: e 19 20- DECAY OF ACTIVITY _
t 17-Jul.90 09:05 AM OnLine Num S-K17: 60 A B 0 0 -E F 0 I J X -
1 NEUTRON ACTIVATION CALCULATION 07/17/90 2 S AMPLE N AME:
09:06 AM l
3 4 ----------------------------------------------------------------ION.
PARENT l DAUGHTER ACTIVITY l .!RRA01AT 5 Element Mass ltsotope Curies l Isotope Curies l CON 0!TIONS 6 --------------+------------------+------------------+-.---------------
7 Na 0 00 l Na24 0.000 l Fe59 0.000 l Flux: 5.0E+13 <
a Mg a.41. l Mg27 0.000 l Co68- 0.000 l Time: ISO 9- At f.44.l A128 0.076 l Co60 0.000.l 10 Ti G.65 ; Sa&& 0.000 l Ni57 0.000 l Moderator Temp /
j 11 Cr 0.93 l Sc47 0.000 l Ni65 0.001 l(Deg C): 185 12 Mn 0.10 l Sc48 0.000 l CuG4 0.001 l 13 Fe 3.51 Tt45 0.000 l CuG6 0.035 l Fast' Flux
-14 Co 0.05 . ; tis 1 0.01A-l Mo93 0.000 l Factor: O'. 8 15 Ni 0.47 l Cr51 0.000 l Mo99 0.000 l
- 16. Cu 0.02 l- Mn64 0.000 l Mo101 0.000 l Cooling Down Mo 0.00 l Mn56 0.169 l Ta182 0.000 l Ti me : 60 17 18 Ta 0.00 l TOTAL: 1.096 l Mode: o
............................................................. . ..a..
19 20 DECAY OF ACTIVITY Q.
09:06 AM online Nuer- .
17-Jul-90 7% .
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! Attachment 5 Microshield Results for cable containing Mn-56
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. . . - -. . - . . - . - . . - .. - - . . - . _ - - . . . - - - . . . . - . - . . . - . .. . ~ .
u n c o m mmh d a nsa ;L. x 1 (Catolim ?tnner & 11tyttt. -#059)
Page- : .~ 1 File Ref:-
File :-CABLE 120.MSH Date: /- /
-Run date: November-27, 1990 By:.
'Run time: 8:45'a.m. Checked:
' CASE:-Cable - Manganese 56 - 120 sec Irradiation GEOFITRY'7: Cylindrical source from side - cylindrical shields l
Distanco tc, detector......................... X 0.422 cm. I
-Source-lent:th................................ L 45.720 l
-Dose point' height from base....-.............. Y 22.860 "
Source cylinder radius....................... T1 0.323 1 Thickness of-second shield................... T2 0.099 - l Microshield inserted air gap................. air 0.
Source-Volume: 14.9462 cubic centimeters i 1
MATERIAL DENSITIES (g/cc):
Material- Source Shield 2 Air gap Air- .001220 Aluminum.
. Concrete Hydrogen Tron- 7.860 Lead Lithium
= Nickel ,
Tin- .. !
-Tun'gsten l Urania. -l
' Uranium Water -1. 0 .I Zirconium H i::
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Jp; r4 h. rAmrrisa y T2EE:: Iatals .- P 55 .I2D sec "?t'rndint:dren BUILDUP FACTOR: based on TAYLOR method.
Using the' characteristics of the-materials in shield 1.
INTEGRATION PARAMETERS:
Number.of lateral angle segments (Ntheta)..... 11 Number of azimuthal angle segments (Npsi)..... 11 Number of radial-segments (Nradius)-........... 11 SOURCE NUCLIDES:
Nuclide' Curies .Nuclide Curies Nuclide Curies Al-28 0.0000e+00 Cr-51 0.0000e+00 Mg-27 0.0000e+00
'Mn-56 5.8360e-01 RESULTS:
Group Energy Activity Dose point flux Dose rate
- (MeV) (photons /sec) MeV/(sq'cm)/sec-(mr/hr) 1 3.3672 3.629e+07 1.521e+06 2.073e+03 2 2.9609 6.618e+07 2.440e+06 3.505e+03 3 2.6641 1.409e+08 4.688e+06 6.971e+03 4 2.5234 2.135e+08 6.732e+06 1.020e+04 5: 2.1172 3.096e+09 8.226e+07 1.312e+05 6 1.8047 5.871e+39 1.332e+08 2.244e+05:
7 1.3516 3.512e+07 5.977e+05 1.076e+03 8: .8516 2.135e+10 2.301e+08 4.578e+05 9
10 11' 12
.13 ,
~
14 15 16:
17
- 18 19-
- 20
- TOTALS : 3.081e+10 4.616e+08 8.371e+05 y
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Attachment 6 Microshield Results for Insulators in TIP Containing Al-28
- , . - . . -.. . .-. - - . - . _ ..~ _ . -.. .~. -. . . . - . . _ ._
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W 3 L1 (Carolina Power T 11tJt rt - #059)
File : TIPAL120.MSH Date: / /
Run date: November 27,'1990 ' By : -
Run time: 8:47 a.m. Checked:
CASE: _ Holding TIP - Aluminum-28_- 120 sec. Irradiation GEOMETRY _7: Cylindri' 1 source from side - cylindrical shields Distance to detector.......................... X 0.367 _cm.
Source length................................ L 2.540 Dose - point . height f ro ~ base . . . . . . . . . . . . . . . . . . Y 1.'270 ' "l Source cylinder radias....................... T1 0.216 Thickness of second shield................... T2 0.052 Thickness-of third-shield....................-T3 0.099' Microshield inserted air gap................. air 0.-
Source Volume: .373706 cubic centimeters-MATERIAL DENSITIES (g/cc):
' Material Source Shield 2 Shield 3 Air gap
. Air- .001220
. Aluminum
. Ca rbon --
Concret'e Hydrogen ...
, Iron. .'7.860 -l Lead Lithium- 1 Nickel' Tin:
-Urania?
-Uranium Water,.. 1.0- t
, Zirconium AlO *
- Alumina 3.970 r
..,c. , ,. . , . . . , ,.c. y _ , , w_,_. . ,m.-
2 age i JMe: Namn_simusir tagg: -q m - :himrismen.23 -- D .uusuc. Thintirm l BUILDUP FACTOR: based on TAYLOR method.
Using the characteristics:of.the materials in shield-3.--
INTEGRATION PARAMETERS:
Number-of lateral angle segments-(Ntheta)..... 11 Number of azimuthal angle segments (N 11 Number: of- radial - segments (Nradius) . . psi) .....
......... 11 SOURCE NUCLIDES:
Al-28:- 7.7700e-01-curies:
RESULTS:
Group. Energy Activity. Dose-point flux Dose rate-
- - (MeV) (photons /sec) MeV/ (sq cm),' soc (mr/hr) i 1 1.7734 .2.875e+10 .1.188e+10 2.-010e+07 2-13 !
4 ,
5-7 8
9 10' 11 !
12 13:
141 15 ;
16 17 18 19' 20
- TOTALS :' 2.875e+10- 1.188e+10- 2.010e+07 t
t
Attachment 7 Microshield Results for TIP Outer Shell Containing Mn-56 l
l l
l l.-
l
1
-o, 6-l edewesshinine m l (Carolitra ?mnrr & 11tp:t - #059.)
File' .: fIPOUTMN.MSH Date; / /- '
Run date: November.27, 1990 By:
Run time:.8:54~a.m. Checked:
CASE: TIP - Outer Cylinder - Manganese 56 - 120 sec. Irradiation GEOMETRY 7: Cylindrical source from side - cylindrical-shields.
-. Distance to detector......................... X 0.367 cm.
Source length................................ L 5.080 "
-Dose point haight-from base................... Y 2.540 "
Source cylin -ar radius . . . . . . . . . . . . . . . . . . . . . . . T1 0.268 "
Thickness of second shield................... T2 0.099 "
Microshield inserted air gap................. air 0.
Source Volume: 1.146 cubic centimeters MATERIAL DENSITIES (g/cc):
Material-Source _
Shield 2 Air gap Air .001220
. Hydrogen Iron- 7.860 Lead Lithium
-Nickel JTin; Titanium l Tungsten L Urania Uranium
- Water 1.0 L Zirconium p
p l
'1
)2m12EE:
2 ,y.iJac mm M - antaur cyli* - W 55 - 17.D mac. rrradimeteen !
BUILDUP FACTOR: based on TAYLOR method.
Using thi characteristics of-the materials in shield 1.
INTEGRATION PARAMETERS:
' Number of lateral angle segments (Ntheta).-.... 11 Number of azimuthal angle segments (Npsi) . . . . . 11 Number of radial segments (Nradius)........... 11 SOURCE NUCLIDES:
Mn-56: 3.2400e-01 curies RESULTS:
t
-Group ~ Energy Activity Dose point flux Dose rate-L #
MeV- (pt
.(. _ _ _-__'otons/sec)
.). . __________
MeV/ (sq .:m)/sec (mr/hr) 1 3.3672 2.015e+07 8.455e+06 1.152e+04 l- '2 . 2.9609 3.674e+07- 1.356e+07 1.948e+04 3 2.6641 7.823e+07 2.605e+07 3.875e+04 4 2.5234' -1.185e+08 3.742e+07 S.670e+04 K- 5 2.1172- l'. 719 e + 09 4.571e+08 7.290e+05 6- 1.8047' 3.~259e+09 7.407e+08- 1.247e+06
- 7. 1.3516 1.950e+07 3.315e+06 --5.988e+03 8 .8516 1.185e+10 't.285e+09 2.556e+06-l- 9 ln 10- ,
11 12.
13 14 15-16
'17 18 19 20 L
TOTALS: 1.710e+10 2.571e+09 4.664e+06
L?t?;
unawamhsmad L u (tarolitia h T~'Liigitt - #U59)
Pa e : 1 File Ref:
Fi e' : TIPINMN.MSH Date: / /
Run date: November 27, 1990 By: 1 Run time: 9:01 a.m.- Checked
- l CASE: TIP - Inner cylinder - Manganese 56 - 120 sec. Irradiation l GEOMETRY 7: Cylindrical source from. side - cylindrical shields [
Distance to detector...................'....... X 0.367 cm .-
Source 1ength......-.......................... L 5.080 J Dose point height from base.................. Y 2.540-Source cylinder radius..-....................... T1 0.216 .
Thickness of second shield................... T2 0.099 Microshield : inserted air gap. . . . . . . . . . . . . . . . . air 0.052 "
Source Volume: .747412 cubic centimeters MATERIAL DENSITIES (g/cc):
!L .terial Source. Shield 2 Air gap Air .001220
- Iron 7.860
. Titanium Tunasten Urania
!Uranit'm ~i Water 1.0
-Zirconium I
l t
1
i l
. E a g e .2 E(3m: Prnammt.gser
BUILDUP FACTOR: based on TAYLOR method.
Using the characteristics of the materials in shield 1. .
INTEGRATION PARAMETERS: ,
Number of lateral angle segments (Ntheta)..... 11 Number of azimuthal angle segments (Npsi)..... 11 Number of radial segments (Nradius)........... 11 SOURCE NUCLIDES: L Mn-56: 2.1100e.01 curies RESULTS:
a Group- . Energy Activity Dose point flux Dose rate
- O. N) . (photons /sec) MeV/(sq cm)/sec (mr/hr) 1 3.3672 1.312e+07 5.378e+06 7.328e+03 2 2.9609. 2.393e+07. 8.627e+06 1.239e+04 -
3 2.6641 5.094e+07 1.657e+07 2.464e+04 4 2.5234 7.719e+07 2.379e+07 3.605e+G4~
5 2.1172 1.119e+09 2.905e+08 4.633e405 ,
6 1.8047 2.123e+09 4.706e+0B 7.925er05
. 7 1.3516 1.270e+07 2.115e+06 3.805et03 8 .8516 7.719e+09 8.164e+08 1.624e'r06 9
10 -
11 12 13 14 15 '
16 17 18 19 20 TOTA *0: 1.114e+10 1.634e+09 2.964e+06 l
l L. = - . . . - - ..
l i
I i
1 l
l Attachment 8 Gar.ma Dose Summary for TIP Incident t
l-I 1
I 1
1
_ _ _ _ - - - __ . - _= - . _ _ _-_ - _ _ . - . - = _ _ _ _ - _ . . . _ _ .
i i l
I Gamma Dose Summary for the TIP Incident i (All calculations performed using Microshield, Rev. 3.11) !
Irr. Dose Dose Exp.
Time Activity Rate Rate Time Dose Object Nuclides (sec) (C1) (mR/h) (R/s) (sec) (R)
Cable Mn-56 120 0.584 837100 0.233 3.0 0.698 TIP Mn-56 120 0.113 1720000 0.478 0.0 0.000 1 TIP Al-28 120 0.777 20100000 5.583 0.0 0.000 Total: 0.698 ;
l i
Irr. Dose Dose Exp.
]
Time Activity Rate Rate Time Dose object Nuclides (sec) (Ci) (mR/h) (R/s) (sec) (R)
Cable Mn-56 180 0.874 1252925 0.348 4.0 1.392 TIP Mn-56 180 0.169 2572389 0.715 0.0 0.000 TIP Al-28 180 1.017 26308494 7.308 0.0 0.000 Total: 1.392 Irr. Dose Dose Exp.
Time Activity Rate Rate Time Dose Object Nuclidos (sec)
(sec) (C1) (mR/h) (R/c) (R)
Cable Mn-56 300 1.449 2078406 0.577 4.0 2.309 TIP Mn-56 300 0.280 4261947 1.184 0.5 0.592 TIS Al-28 300 1.332 34457143 9.571 0.5 4.786 Total: 7.687 i
e-e.-n. ,---.,,sw.. ,w-e.. ,m , .,em . ,,_.. ,,m -y , w, 4
l 1
1 I
l 1
l l
Attachment 9 Data Dose Summary for TIP Incident i
.l l
I
- - -- ~ . - . - - . .-_ _ . - - . _ _ - . .- _. . . - - __- . _-. -
1 1
Beta Dose Summary for TIP Incident l
i Irr. Exp. Dose ;
1-Time Time Rate Dose Object Nuclido (sec) (sec) (rad /s) (rad) !
Cable Mn-56 120 3 1.541 4.623 TIP Mn-56 120 0 2.406 0 TIP Al-28 120 0 21.109 0 Total 4.623 .
1 i
Irr. Exp. Dose I Tine Time R te Dose l Object Nuclide (sec) (sec) (raw,*) (rad) l
..................................................... 1 Cable Mn-56 180 4 2.307 9.228 TIP Mn-56 180 0 2.406 0 TIP Al-28 180 0 21.109 0 Total 9.228 Irr. Exp. Dese Time Time Rate Dose object- Nuclide (sec) (sec) (rad /s) (rad)
Cable Mn-56 300 4 3.827 15.308 TIP- Mn-56 300 0.5 5.968 2.984 TIP Al-28 300 0.5 36.186 18.093 Total: 36.385 i'
e + - . + _ . m aw... ~-
.v%-. , e v ..,ys3 y p n -w-*i --
+y *, - --
l l
Attachment 10 As a result of the Department of Labor proceeding brought by Mr. Larry Dew against CP&L and CDI Corporation, CP&L conducted an
. investigation into the allegations. Part of this investigation centered around the radiation dose assigned to Mr. Dev.
The investigation of the dose assignment was divided into two parts: 1) the assumptions, and 2) the dose calculation methodology. The investigation regarding the assumptions was conducted by Mr. Mike McGarry and Mr. Don Meindertsma, counsel from the law firm of Winston snd Strawn, Washington, DC, and, assisting at their direction, Mr. B. H. Webster, Manager of Corporate Health Physics for CP&L. The second part of the investigation that looked at the methodology for the dose calculation was conducted at the direction of legal counsel by Mr. Steve Browne and Mr. Jay Terry, technical representatives of CP&L, with assistance from an outsido consultant, Mr. Robert Alexander.
In looking at the assumptions the investigation team sought the answers to four questions:
- 1. How long was the TIP in the core?
- 2. How far back from the detector did Mr. Dow grab the cabic?
- 3. Did Mr. Dew actually touch the TIP detector?
- 4. How long was Mt. Dew's hand in contact with the TIP cable /dotector?
In order to obtain answers to those questions, everyone involved or who might have knowledge of the incident was questioned, except Mr. Dow, who was not available. In all this included about 26 people, some of whom were questioned :nore than one time.
In answering those questions, the investigation team determined the most probablo scenario and also determined the upper and lower bounds for the assumptions as summarized in the table below.
I
-- y.,. , - . , .
_ _ __ _ _ m. . _ _ . _ . - - _ _ . - _ _ _ _ _ _ . _ _ . _ . . _ _ . _ _ - _ . _
7___
J-i.
i e
1 l'
8UMMARY OF...A88UNPTIONS l 1
e Lower Most Upper j j Bound Probable Bound i
l Time detector in core 2 min. 3 min. 5 min.
Distance from hand to 7 inches 7 inches 7 inches detector Hand contact.with detector o sec. O sec. 0.5 sec.
Hand in contact with cable 3 sec. 4 sec. 4 sec.
The findings-of the investigation team with respect to the four
- questions and the conclusions regarding the assumptions used it; the dose calculations are discussed below.
[
l 1. How Lona was the TIP in the core?
People who were involved in the work associated with this incident and others who were familiar with this type of work were questioned. Those people most familiar with the TIP -
operation stated that the TIP could not have been in the core more than two to three minutes. Only one person
. indicated that it could have been in the core as much as ;
five minutes.
'Also, the dose recorded on the whole body badge -
4 substantiates the assumption that the TIP was not in the ,
~
core for a much longer period. If the TIP had been.in the core for eight to twelve minutes as-alleged by Mr. Dew, our calculations show his whole body badge.would have shown ;
between 1,000 and 1,200 mrem. In fact, tha whole body badge ,
registered 405, which is consistent with the TIP being in the core for two to three minutes. For these reasons the investigation team believes that the best estimate of the time the detector was in the core was three minutes, with a .
range of_two to five minutes.
- 2. How far back from the detpctor did Mr. Dev arab the cable?
-Fo11'owing the incident, witnesses recalled that:Mr. Dew
-repeatedly stated that he grabbed the cable about 12" from 4 4 the detector and_re-inserted it in the tube. However, in reenactment of the incident, Mr. Dew grabbed the cable as close as 7" from the detector. Consequently, for all cases, it was assumed that Mr. Dew's hand was on the cable 7" from the detector.
._ . _ _ _ . _ . _ _ _ . . .. _ .._ ._. _ . _ _ _ _ _ _ . , . . _ . _ _ . - . . . . _ . - . . . . ~ _ .-
l
- 3. Did Mr. Dev actually touch the TIP detector?
l Witnesses reported that in conversations with Mr. Dew 1 immediately after the incident and during the next five days, Mr. Dew always stated that he did not touch the detector, even when specifically asked. Also, during every l reenactment of the incident, he grabbed the cable, never touching the detector. The technician who was working with Mr. Dew during the incident stated that he did not see Mr. Dew touch the detector. He stated that he saw Mr. Dew re-insert the TIp and-did not observe him touching the detector. However, this technician said that althvugh he did not see Mr. Dew touch the detector, he could not absolutely state that he did not.
About five days later, Tuesday, July 10, 1990, Mr. Dew stated to one of the members of the original investigation team that he was now not sure that he did not touch the detector. At this time he told the invertigator that he could have touched the detector, but if 'te did, he just brushed it before grabbing the cable. He demonstrated how this was.possible and the investigator timed him. During this reenactment, the time that Mr. Dew's hand was in contact with the detector was about 0.4 seconds.
People familiar with this job and who had performed the job numerous times thought that it would not have been possible to grab the detector, release it, and then grab the cable.
The cable is on a reel that is spring-loaded and would have been pulling on the cable. They all indicated that if you released the detector it would have retracted to the point of completely winding up on the take-up reel. This is further evidence that Mr. Dew did not touch the detector.
The investigation team feels very confident that based on the evidence, Mr. Dew did not touch the detector and that was the assumption used in calculating the most probable dose to his hand. However, in calculating the upper bound of the dose, it was assumed that his hand was in contact with the detector for 0.5 seconds.
- 4. Hov Jona was Mr. Dev*9 hand in contact with the cable / detector?
Immediately following the incident, Mr. Dew repeatedly stated to management and HP personnel and demonstrated that his hand was in contact with the cable thr:e seconds.
Several times he demonstrated how he grabbed the cable and re-inserted it in the time required to count "1, 2, 3."
During timed reenactments of the incident Mr. Dew always took three seconds or less to re-insert the TIP. However, later Mr. Dew indicated to one of the investigators that he, on his own, had attempted reenactment and he thought that it
4 4
might have taken longer than three seconds, maybe about four seconds. Based on this last statement and to be conservative, the investigation team recommends using four seconds for the most probable time and three seconds for the lower bound. For the upper bound the four seconds in contact with the cable should be used; but as previously stated, it is also assumed that his hand was in contact with tne detector for 0.5 seconds.
.M n/2 abo l'
i i
l
4 f
Attachment 11 Independent Evaluation of Dose calculations I
l l
l l
~= _
A _EXA N J E R mp --
( R.E. ALEXANDER Prevoent LG ,
1 1
November 19,1990 Stephen A. Browne .
Principal Specialist - Health Physics '
I Carolina Power and tight Company P.O. Box 1551 Raleigh, NC 27602
Dear Mr. Browne:
At the request of Billy Webster, CP&L, I have reviewed your calculations of the dose received by the left hand of a CP&L employee on July 5, 1990. Details regarding this incident and the calculations appear in the document " Brunswick TIP Incident Dose Calculations' that you recently sent to me.
Regarding the gamma dose, which is only a small percentage of the-total, I obtained and examined the Grove Engineering computer program MicroShield that was used for this calculation. The program is tecnnically sound and is widely used in the nuclear power industry. The manner in which the program was used is correct. The best-estimate gamma dose at a tissue depth of 0.007 cm (about 1.4 rem) may be considere.bly overestimated since na correction for lack of electronic equilibrium at this depth waar included in MicroShield. I discussed this problem with Dr. Daniel Reece, Texas A&M University. He is sending information t o me-regarding work on corrections of this type that has been completed-at Battelle Northwest Laboratories. It may be feasible to make the-correction if you so desire.
During my visit with you at Brunswick we carefully reviewed your calculation of the beta dose, which resulted in a best estimate:ofk about 9.2 rems. Your use of equation 24 from Radiation Dosimetry.
l Hine and Brownell, appeared to me to be technically sound. The l only reservation I had was about the manner in which the correction I
for self absorption by the source (cable in this case) is made by this equation. In a subsequent meeting that I attended with you, Mr. John Potter of the NRC requested a verification of your result; and at the request of CP&L I have conducted a rather thorough-study.
l 13131 MalteseLane+FairfacVirginbr22033- -
Telephone (703) 6318878 Telefax (703) 6318642
My first cont act. was with Sydney Porter who has developed a computer program for performing beta dose calculaticns. This program is based on tables published by W. G. Cross, Chalk River
, :.aboratories (" Tables of Beta Ray Dose Distribution in Water, Air and Cther Media", AECL-7617, '982). Unfortunately, the capability of .orter's program is 2imited to infinitely thin plane source terms for which the questien of beta absorption by the source
- tself does not arise. However, you had indicated to me that the correction provided by the Hine and Brownell equation was 0.5; tnus the results of Porter's equatien, multiplied by 0.5, would provide in estimate that could be cor: pared with yours.
Using the Mn-56 total cable activity q of S.241 Ci that you provided, the exterior cable circumf erence C of 0.785 inches, a length L of 9 feet, and a thickness t of 0.125 inches for the cable, and an infinite thickness t of 2 mm for 2.85-MeV betas in
- ron, estimated an infinitely thin source term of 6000 pCi/cm; as the necessary input for Porter's program. The following equation was used
o=LC7 x1C The ratio t/t eliminates Mn-56 that does nc* contribute to the surface dose rate. An activity distribution e tor was of necessity introduced in the conversion of the actual hollow cylinder to a rectangular plane. However, I believe the dose to the maximally exposed square centimeter of skin would be approximately the same frem either geometry.
Using the previously mentioned input the following results, multiplied by 0.5 as in the case of the Hine and Brownell equation, were obtained:
i Depth (mg/cm;) Dose Rate (rads /sec) 7 6.7 20 5.0 99 2.3 112 2.2 l Regarding the depths, a density of 1 g/cm 3 was used f or the rubber l gloves worn by the exposed person (92 mg/cm;) and for tissue (7 mg / cm;) . For an exposure of 4 seconds at 99 mg/cm;, as used for your calculation, the estimate would be 9.2 rads. This result is
the same as obtained f rom the Hine and Brownell equation. t ades confidence in your result but does not investigate the accuracy of the Hine and Brownell self-absorption correction.
To investigate the self-absorption phenomenon I contacted Dr. F. H.
Attix. who recommended a Monte Carlo simulation using a code '
written at the University of Wisconsin under the supervision of Dr.
Thomas R. Mackie. Dr. Mackie agreed to perform the calculation, using input data that I provided in a letter approved by you and dated October 24, 1990, Attachment 1. His results were sent to me on November 12, 1990, Attachment 2. At 100 mg/cm2 the dose rate is shown to be 131.5 rads /sec per Ci of Mn-56 per gram of iron, with a standard deviation of 9.3 rads /sec. The dose rate associated
+
with a specific activity of 0.0189 Ci/gm is 2.485 rads /sec. For a 4-second exposure the dose would be approximately 9.9 rads. ,
The Hine and Brownell equation was developed before current Monte
~
Carlo methods were computerized and does not account for self absorption with the accuracy of the Monte Carlo simulation. For '
this reason I recommend acceptance, f or purposes of compliance demonstration, of the 9.9-rad beta dose estimate at a tissue depth of 7 mg/cm;, the depth required by 10 CFR Part 20. For purposes of the CP&L medical record, I recommend recording also the dose at a tissue depth of 40 mg/cm;, the depth at which the cells at risk i (the basal cell-layer) are likely to be located (ICRP Report 23).
At a total depth of 1.50 mg/cm , Dr. Mackie reports a dose rate of 2
110.1 rads /sec per Ci/gm, which would be 2.08 rads /sec from the.
cable. Thus the recorded beta dose would be 8.3 rada. If the-actual depth to the basal cell layer is desired, it may be possible
, to obtain it through examination by a dermatologist. Recomputation '
of_.the dose might then be in order.
j Please note that my analysis did not include teview of assumptions such as the . neutron irradiation ttne for the cable in the reactor core, the activation determinatir,n, or details of.the exposure such the location of the hand on th'., source and the time of exposure.-
Please call on me if I can b1 of further assistance.
Sincerely,
~ Robert E. A exander-
Enclosures:
Attachment 1, letter to Mackie Attachment 2, response from Mackie cc: J. Michael McGarry Winston and Strawn
__9. .G.T - RA . T.6....W_Fi.P A L.J. A .E._ _. . .. .. .... .. ._ . . . . - . . _. . . . . _. . . . fa .OM. .
y A_EXA\ J E R "
]y R.E. ALEXANDER
} President I october 24, 1990 Dr. Thomas R. Mackie /0/2.kfo Department of Medical Physics University of Wisconsin hb i [o od ,,,, hf 4Se.
/
1300 University Avenue $j$ l00 }
Koom 1530 @o .54t4//g' Madison, Wisconsin 53706 l ##
4 5&
.k C R P 2,. I .'
fVDCtC poar Dr. Mackie YN 2 w"d I S m bbetame In connection with our recent discussion about a radiation skin dose calculation that you expressed willingness to perform, I am pleased to say that rny client has autherned the work. To expedite the administrative aspects, the work will be performed for my corporation; and your invoice should be directed to me at the address shown on the letterhead.
The information that you will need is provided below:
- 1. The radionuclide is Mn-56,
- 2. The quantity to be used is 1 Ci.
- 3. The radionuclide is an activated impurity uniformly distributed in an Fe slab of infinite area and of thickness greater than the range of the maximum Mn-56 beta (2.85 MeV) .
- 4. The beta dose rate is to be calculated in units of rad /sec.
- 5. Exposure configuration: the palm of the hand is pressed against a flat Fe slab.
- 6. The beta dose rate is to be provided at the absorber depthe listed below, assuming for each depth an absorber density of 2
1 g/cm:
0 mg/cm 8 7 "
99
, 114 129 "
l I will be expected to provide a report to my client in suf ficient detail to satisfy any regulatory and legal needs t. hat may arise. For this reason I would appreciate receiving from you a brief description of the computer program you will use. The l
target audience for this description would be health physics l
l 13131 Mattese lane
- Fairfax, Virginia 22033 Telephone (703) 6318078 Telefax (703) 6316642
. 9.9_7.. 3.9 - ..t R . J.J.K.P. .A.A.J.J .t. . . ._..__..-......................2..r_9M....
personnel employed by the Nuclear Regulatory Commission (NRC). A copy of your CV would also be beneficial for this file.
In accordance with our telephene conversation, I have infomed my client (1) that the calculations will be performed by you er under your direct supervision and that authenticated by your signature, (2) that the fee will be based on the results will be a rate of $100 more extensive,per andhour, (3) that or $500 i day per day might beif athe timeestimate good requirement is for the calculation as I described it over the telephone.
I am very happy to have this opportunity to work with you. My friend Frank Attix has spoken very highly of your capability and standing in the beta desimetry fields it is very fortunate that you are in the positien to help us at this time. The NRC has requested a dose report f rom my client within 2 weeks, and it is my understanding from you that this schedule is compatible with the amount of time you are likely to need.
Please call me if additional details regarding the exposure are needed for your calculationo.
Sincerely, Robert E. Alexander
UNnT.RSrn' Of WLSCONSIN-MADLSON MEDICAL SCHOOL Nov.12,1990 Robert E. Alexander j The Alexander Corporation 13131 Maltese Lane Fairfax, Virginia 22033
Dear Dr. Alexander,
Find enclosed the results of a Monte Carlo simulation involving nn exposure from d particles emitted from 5'Mn. I apologize for the delay of the weekend, but we wanted to do some additional tests of the simulation to verify tha't the simulation was free of any systematic errors.
The Monte Carlo code used was EGS4 (Electron Gamma Shower Version 4) originally writ.
ten by Ralph Nelson e.nd colleagues at the Stanford Linear Accelerator Center and modified and benchmarked for low energy transport by David Rogers and colleagues at the National Research Council of Canada. The specific user code is called XYZDOS was written by David Rogers and Alex Bielajew and modified, under my supervision, by Mark llotmes to model radioactive sources. Collaboration was also provided by two other students: Tim llotmes and Douglas Simpkin. As agreed during our telephone conversation additional documentation de-scribing this code can be supplied by us, however, EGS4 is widely described in the literature (eg. Nucl. Inst. and Methods, Medical Physics, Phys. Med. Biol.)
i addition to the specific details of the simulation we conducted several tests of the code to ensure its correctness. Specifically we:
. tested that energy was being conserved for different munbers of histories (simulated particles) e tested that for conditions of charged particle equilibrium that the simulated dose rate in homogeneous water and Fe phantoms agreed with the equation:
dD A (7)0 = pE( As-h Depanment Of Mqdical Physics 1530 Medca15aences cen:er 1300 l'niwrsity Avenue Maison. W153706 t06!2t2-2170
where (@)g is the dose rate, f is the activity per unit mass and (6 3. ), is t he equilibrium dose rate constants for bins describing the beta spectrum for Mn, the sum of which is the mean energy of beta particles per decay (0.832 MeV or 4.91 x102 g . rad /(Ci . s).
. ensured that the S were being emitted uniformly in the source region and isotropically distributed in direction.
According to your specifications of the problem outlined in your FAX of October 21 and in our telephone conversations we simulated the geometry described by the accompanying diagram.
Briefly, it consists of a 12 cm x 12 cm slab of iron (density = 7.80 g/cm 3) that contains a uniform isotropically emitting source of 5'Mn. The thickness of the slab is 0.5 cm which is greater than the range of the betas in iron. The scoring region consisted of 20 slabs 8 cm x 8 cm by 0.01 cm thick centered beneath the Fe slab. The scoring region was surrounded by 2 cm of water to the sides and 1.8 cm of water below to ensure scatter equilibrium to the scoring region. Only the dose from beta particles was simulated (the dose from gamma or internal bremsstrahlung is not to be included).
The tabulation of Browne and Firestone (enelosed) was felt to be too coarse so the beta spectrum of 58Mn was obtained from Douglas Simpkin using a code described in the literature (Simpkin and Mackie, Med. Phys.,1990). It consisted of 49 spectral bins and a plot of the spectrum is enclosed including a comparison with Browne and Firestone. The simulation consisted of running 1000 simulated decays for each of the 49 bins for a total of 49,0()0 histories.
The probability of emission from each of the bins (as expressed in munbers of histories per 10,000 decays) was used to weight histories starting from each of the bins. The simulation was run on a Sun Sparcstion-1 computer.
The dose rate per Ci/g (([M for any of the scoring region slabs was obtained from the following equatiom dD/dt M,,,,,, [p) . D"*"lGy)
( A/M){ rad . p/(Ci . a)) = 3.7 x 10*Bq/Ci Gy 100 Arad s,,,, .
where D,,,,,[Gy) is the dose in Grays scored in a water slab, M,,,,,,[pl is the mass of the source region in grams which was 505.9 g, and Ns,,,, is the number of simulated decays in the i source region.
For the particular geometry used the following equation is more convenient:
1 2
dD/dt 35
( A/M)'rnd i
. y/(Cf . s)] = 2.09Gy/x decay 10 [ rad g!(Ci . s)} ' b,a,e,/D,,,,, I The tabulated and graphed results are enclosed. The dose rate in rad /s per Ci/g from beta particle emission in the first scoring region past the interface (the interface is located at 0.5 cm) is 2.49 x102 g . rad / (Ci . s) and rapidly falls to values between about 1.2 to 0.6 x10 8 g . rad / (Ci s) at 0.1 cm to 0.2 cm past the interface, respectively The percent statistical uncertainty (100 x standard deviation /value)is typically less than 5Fe.
The value near the' boundary is within 2 To of what one would expect from the simple dosimetric approximation of assuming an equilibrium spectrum of betas from a semi.mfinite slab source (i.e. half the equilibrium dose rate or if x108 g rad /(Ci s). This is fortuitous for twc reasons. The accuracy of the simulation is not within 27o. The simple analytic estimation is very crude. Including the ratio of mass collision stopping powers between water and iron would have increased the crude estimate by about 30 to 40re and including the lack of an equilibrium scatter would tend to decrease the result by a similar amount. Of course the Monte Carlo simulation takes both of these effects into accoun* implicitly.
This report is being sent by FAX, but will be followed up with a ietter that will include a longer run with less uncertainty. At that time, I will also include the raw output from the Monte Carlo simulation which lists some of the details of the particle transport and a reprint of the Simpkin and Mackie paper. Iiiope that you find these results useful and please let me know if you have any other questions or concerns.
Accompanying the letter will be an invoice from the UW Medical Physics Department for
$2,000. It will fund for travel expenses for graduate students working in our radiation dosime-try research group.
Bess regards. Yours sincerely, I
T.R. Mackie Assistant Professor (608) 202 7358 l
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Table of Radioactive Isotopes Edgardo Browne ana Richard B. Firestone Virginia S. Shirley, Editor c
Lawrence Berkeley Laboratory University of California A Wiley interscience Publication !
JOHN WILEY & SONS
. New York Chicheste" -
Brisbane - Toronto - Singapore
~ _ _ _ _ _ - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ __
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- 6 2 Atomic Electrons ("Co) .
1gp Vfd f M Pholons ( 5'C0) 8mmd (v)=3375J2 key l
Mode: $.
)(gey) gg)t 'mnM HM W A: .$6908.4 n kev 3 ,,,,
aum691se spa: 2.1702x 10 Ci/g 129. ivi 0008n "I "'" "U5' ' 8328*8 %0 0 N54 "ND48 8
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Prod: "Mn(n t) h L. 0 628 402is 14% .1462 Os0N2904 2.01 ss x17 4 >
h L. 0.705 0.29 ' t633 1640 6.8 x10 4 i5 se x60 0.00089 e i Fe L, 0726 0.22 e 1764 . I810 0.0156 73e 0.000496 n Photons ( gMn) Te K. 6.391 1957 2034 0.0100 1414 xt0 4
""*' 6 44 14 4 ' N .2112 a m 0 m L82 se x10 4 ll.~
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t'Ml+E21 486.66 to 0.050 se M50.MM Lt5 x10 4 )
000034e Ml+E21 674 694 0.030 m 29 9 3009 R N 069 231 n x t0 HMI.Gl 787.80 e t 733 64 4 0.192 n 3195 3273 0.0078 0.000241 n TU $46 812 m 98 9s 3 M l+ E21 s t iM l+ E2: 1037.879 n 0 040 s- t M t +E21 787.80 s 03077 D63.Mt EM L65se xia
? E2 1238.317 n 0.n99se i E2 846.812 m 99 9 0.075 ,,
3 m . M U E0@l17 13sxte 0.uD48 s 896 63 e t !Ml + E21 1360.29 s 3 lMi* E21 27.2 s t Ml+E2l 977.484 1.40 s t Mt+3 5%E2 1810.80 e 997.10 e 0 14 s 1 Ml +4 0%E2 2t til9 e 14.3 e M t + E2l 14.1 s
!f" 2276 P s 0.00034 ? i Ml+E2! 1037 879 n Ml+E2! 1089.11 s 0030 m Continuous Radia:lon ("Co)
HE2l t lM l + Di 2522.95 e 0 99 s t Mi+ E21 Ii4046e 0.IN rs 2598.57 s 0.0188 m i (B+)-120 kev;(ll)-0.44 kev t (M l+ E21 nul n n.58. 0 653 m t E2l ' li60.09 e 0 091 ee 2.26 e t jGI 29s9 96 e 0306 is t Mi+E2l 1175.15 s lito s t Ml+E2l 1199.03 s. 0D0:1 ( )l kev) (%)
3;Ul D6932 e Ewn(kev) -
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Continuous Radiation ( 5'Mn) [2 6[8s, 20 ' " # '
16+0.33e 0 063 s lB t E2 (s.)-830 kev;(IB).1.9 kev t'Mi +E21 1771.51e 115s d*# 8'.EE. * '
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!B 0 028 m
( )(kev) (%) t Ml+E2! 196198: W . 2 0+ 68 34 Emn(kev) t Ml+ E21 2015.34 e 3 03 e iB C086 ES7 0.69 t M l
- E2! 2034.96 e 737 u M . 6@ p+ 28.6 63 0 10 8 0.0344 ID 0 03) t Mt+4 0%E2 2t t119 e 0 376 # 2 al20 a028 0104 030 2213.00 s 03M # 600.I E #+ 83 93 10 20 B.
IB 0.030 0.2I tfM1+E2l t E2) ~ 2274.17s 0 120 ,, IB ald) EM 1.43 2373 44 e 0.061 # #+ 1.70 0.127 20 40 6 0 431 3 yt+E2! 00He 1300 2481
.IB 0 059 0.20 t 2522.958 B 0 046 0.0028 4 66 Ml+nj 2598.57 # 16.7s j3+ .0 40 100 s. 1 29 3
. 0 0f 56, IB 0.164 025 t E2 2657.58 t y 'E2 2959 96 e 0 0080 s 100 300 d. n.0 17.4 0,44 0.25 M +E2! 3009.78 e 103 e IB 3 23.0 Ml+E21 3202.25 e 102 n 300 600 A. 101 t 74s IB 0 45 0 106 y MbO! '
3:53604 56 27.0 t E2 3273.23 e 1.7) n 600 1300 4 247 Omus .d, Ni(6.10 2 d) m 0 54- 00o , E2 3a9.72 e 24,5 3451.27 e 0 89 e l300 2500 A. 429 tgU 0.113 rr Mode; e IB 0.17 0 0108 tim ; + E21' 3548 2 s 14 3 0.55 3 3600.86 u 00150 m A: .5390211 kev 2500 2849 s. 4 nii.70 r a00n ,, 5 IB 0.000 % L42 x10 3 spa: 3.822x10 Ci/g t <0.1% uncen(Syst) Prod: 5'Fe(a 2n); "Te(3He.3n) 56 At mie Elunond"Co) Photons ( 5'NI)
T .ble) 26 (e)-3.6 s kev -
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, M i(+408%E2) til 86 s 86.0n 103t . lon 0.034 4 0.002M n "Ni(d.a) 4 1 E2 (M t.8) s 14.0s 1082 108818 x10 7s x10 103. It74 00036 0.00031 s _ .
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(00# !#65T Bound Conter 4, n (ca) (GyADis ) ( 1 ) g rad g rad Ci s Ci s 0.1 2.089 1.4 0.05 437.4 61.2 0.2 2.329 2.2 0.15 487.6 10.7 0.3 2.292 1.8 0.25 479.9 8.6 0.4 2.397 1.7 0.35 501.9 8.5 0.41 2.292 3.2 0.405 479.9 15.3 0.42 2.336 3.9 0 415 489.1 19.0 0.43 2.207 2.4 6.425 462.1 11.0 0.44 2.262 4.6 0.435 473.6 21.7 0.45 2.181 3.5 0.445 456.7 15.9 0.46 2.13 3.5 0.455 446.0 15.6 0.47 2.179 4.4 0.465 456.2 20.0 0.48 2.005 3.6 0.475 419.8 15.1 gf 0.49 1.842 3.5 0.485 385.7 13.5 0.5 1.417 3 .J _ 0.495 296.7 10.3 0.51 1.19 6.3 0.505 249.1 15.6 0.52 1.119 7.1 0.515 234.3 16.6 Y"b!"
0.53 1.017 5.6 0.525 212.9 11.9 0.54 0.9545 6.4 0.535 199.8 12.7 0.55 0.8945 5.6 0.545 187.3 10.4 0.56 0.8297 7.7 0.555 173.7 13.3 0.57 0.7429 4.2 0.565 155.5 6.5 0.58 0.'6767 7.4 0.575 141.7 10.4 0.59 0.6458 6.9 0.585 135.2 9.3 0.6 0.6284 7.1 0.595 131.5 9.3 0.61 0.5662 8.9 0.605 118.5 10.5 i 0.62 0.575 7.2 0.615 120.4 8.6 0.63 0.5258 8.3 0.625 110.1 9.1 0.64 0.547 7.3 0.635 114.5 8.3 0.65 0.4939 7.6 0.645 103.4 7.8 0.66 0.4703 8.2 0.655 98.4 8.0 0.67 0.4712 7.7 0.665 98.6 7.5 0.68 0.4263 8.7 0.675 89.2 7.7 0.69 0.4217 7.3 0.685 88.3 6.4 0.7 0.4114 6.9 0.695 86.1 5.9 0.8 0.2998 5.8 0.75 62.7 3.6 0.9 0.1833 9.7 0.85 38.3 3.7 1 0.09706 15.3 0.95 20.3 3.1 1,1 0.0482 12.0 1.05 10.0 1.2 1.2 0.0173 22.7 1.15 3.6 .8 1.3 0.007569 26 1.25 1.5 .4 1.4 0.0043 30.5 1.35 .9 .2 1.5 0.00141 40.1 1.45 .3 .1 1.6 0.000685 64.2 1.55 .1 .0 1.7 0.000437 81.8 1.65 .1 .0 1.8 0.000802 58.8 1.75 .1 .0 1.9 0.001768 57.1 1.85 .4 .2 2 0.000753 73.6 1.95 .1 .1 2.1 0.003085 56 2.05 .6 .3 2.2 0.002475 61.2 2.15 .5 .3 2.3 0.001004 96.4 2.25 .2 .2 2.4 0.001452 85 2.35 .3 .2 l 2. 5 0.000146 99.9 2.45 .0 .0 l
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(cm)- ( *10 ^-13 ) (%) (cm) Ci s Ci s 0.10 2.090 0.3 0.050 437.6 1.3 ,
0.20 2.307 0.5 .0.150 483.1 2.4 0.30 2.319 0.4 0.250 485.6 1.9 LD.401 2.326. 0.2 0.350 487.1 9.7
.0.41 2.339 1.2 0.405 - 499.8 5.9 0.42 2.344- 1,2- 0.415 490.9 5.9
- 0.43 2.331 1.1 0.425 488.1 5.4 0.44. 2.325 1.5 0.435 486.9 7.3 0.45- 2.274 1.8 0.445 476.2 8.6 0.46' 2.230 1.4 0.455 467.0 6.5 t
0.47- 2.095 0.8 0.465 438.7 3.5 0.48 2.014 0.5 0.475 421.7 2.1 0.49 1.794 1.4- 0.485 375.7 5.3 0.50 1.395 1.6 0.495- 292.1 4.7 re 10.51- 1.182 1.8 0.505 247.5 4.5 Water 0.52 1~.049 - 1.6 0.E15 219.7 3.5 0.53 0.9684 1.2 0.525 202.8 2.4 0.54 0.9039 -1.5- 0.535 Ja9.3 2.8
-0.55 0.8483 2.0 0.545 177.6 3.6 0.56 .0.7894 1.3 0.555~ 165.3 2.1 0.57- 0.7425 1.9 0.565 155.5 3.0 0.58 0.7072 2.6 'O.575 148.1 3.9 0.59 0.6642 2.7 0.585- - 139.1 3.8 0.60' O.6279 2.3 0.595 131.5 3.0 0.61. 0.5963- 2.5 0.605 124.9 3.1 3.2
~
0.62 0.5448- 2.8 ~ 0.615 114.1 0.63- 0.5257 '1.9 0.625 110.1 2.1 0.04' O.4889 2.2 -0.635 102.4 2.3 0.65- 0.4702 3.5 0.645 98.5 3.4
-0.66 - 0.4542 3.8 0.655 95.1 3.6 0.67 0.4236- '2.4 0.665 88.7 2.1
=0.68 0.4062- 2.9 0.675~ 85.1 2.5 0.69: 0.3825 4.2: 0.685 80.1 3.4 0.70 0.3636 4;4 0.695 76.1 3.4 0'80-
. 0.2741= 3.1- 0.750 57.4 1.8 0.90 -0.1364: 3.4 '0.850 32.8 1.11 1.00 0.08974 3.4 0.950- 18.79 0.64' 1.10 0.04546 6.0 1.050- 9.52. 0.57 1.20 0.02002- 6.3 1~150-
. 4.19 0.26 1.30- 0.01070. 12.0 1.250: 2.24 0.27 1.40 0.0051741 15.2 1.350 1.08 0.17 1.50: :0.003473 22.5 1.450 0.73- 0.16 1 ~. 60 - 0.002705 .35.4: 1.550 0.57 0.20 1.70- 0.001906 17.2 1.650 0.399- 0.069 1.80s 0.002143- 33.1 1.750 0.45 0.15 !
l'.90 0.001395. 37.7 1.850 0.29 0.11 :!
2.00: 0.001403 41'.9 1.950 0.29 0.12 s 2.10 ~ 0.000654- 45.8 2.050 ~0.137 0.063 2.20- 0.001738 14.6- 2.150 ~0.360 0.053 2.30 0.001507 22.3 2.250 0.316 0.070 2.40 0.001719 32.7 2.350 0.36 0.12 ,
2.50 0.000666 39.6 2.450 0.139 0.055 fh/M1
- Qa},d &m Y N 7Hb 1 NRCC ' USER CODI ICDOS (V1. 0) USING EGS4 AND PRESTA GEOMETRY IS A PICTILINEAR VOLUME, ORIGIN 10 BOTTOM LEFT,X-Y PLANE ON THE PAGE AND Z AXIS INTO THE PAGE
_, , J .' c . n o.r ea r , . .
TITLE: + The dose t ot big cube of waten perfused with a Mg-56 source spectrum NUMBER OF MEDIA: + 2 .
~'"
MEDIUM 1; + FE MEDIUM 2: + H2OS21 'l * ;
ECUT,PCUT,ESTPE(1 to 2): + O.515 0.515 0.020 0.020
- REGIONS IN X, Y, O DIFICTIONS (IF<0, IMPLIES # GROUPS OF REG) : + 3 3 INPUT BOUNDARIES IN THE X DIRECTION SMALL BOUNDARY FOR FIGION( 1) + 0.000 SMALL BOUNDARY FOR FIGION ( 2) + 2.000 SMALL BOUNDARY FOR FIGION ( 3) + 10.000 OUTER BOUNDARY FOR FIGION ( 3) + 12.000 INPUT BOUNDARIES IN THE Y DIRECTION GMALL BOUNDARY FOR FIGIO!!( 1) + 0.000 SMALL BOUNDARY FOR FIGION ( 2) + 2.000 SMALL BOUNDARY FOR REGION ( 3) + 10.000 OUTER BOUNDARY FOR REGION ( 3) + 12.000 INPUT BOUNDARIEb IN THE Z DIRECTION INITIAL BOUNDARY: + 0.000 WIDTH IN THIS GROUP, NO. OF PIGIONS IN GROUP: + 0.100 4 WIDTH IN THIS GROUP, NO. OF PIGIONS IN GROUP: + 0.010 30 WIDTH IN THIS GROUP, NO. OF REGIONS IN GROUP: + 0.100 18 BOUNDARIES 0.000 0.100 0.200 0.300 0.400 0.410 0.420 0.430 0.440 0.450 0.460 0.470 0.480 0.490 0.500 0.510 0.520 0.530 0.540 0.550 0.560 0.570 0.580 0.590 0.600 0.610 0.620 0.630 0.640 0.650 0.660 0.670 0.680 0.690 0.700 0.800 0.900 1.000 1.100 1.200 1.300 1.400 1.500 1.600 1.700 1.800 1.900 2.000 2.100 2.200 2.300 2.400 2.500 0 TOTAL # REGIONS INCLUDING EXTERIOR = 469 OINPUT GROUPS OF REGIONS FOR WHICH DENSITY AND MEDIUM ARE NOT DEFAULTS I LOWER, UPPER I, J, K, MEDIUM, DENSITY +( 1 3) ( 1 3) ( 1 14) 1 7.860 Things have been forced to comply with the following geometry I=1. 3,J=1. 3,K=1. 14 rho =7.86 med=1 (Fe)-
I=1. 3,J=1. 3,K=15 52 rho =1.00 med=2 (H2O) ,
LOWER, UPPER I, J, K, MEDIUM, DENSITY +( 1 3) ( 1 3) ( 1 52) 2 1.000 Things have been forced to comply with the following geometry I=1. 3,J=1. 3,K=1. 14 rho =7.86 med=1 (Fe)-
I=1. 3,J=1. 3,K=15. 52 rho =1.00 med=2 (H2O)/
LOWER, UPPER I, J, K, MEDIUM, DENSITY 0 INPUT GROUPS OF REGIONS FOR WHICH ECUT AN LOWER, UPPER I, J, K, ECUT, PCUT0 ENTER 3 PAIRS DEFINING LOWER, UPPER X,Y,Z INDIC FOR WHICH RESULTS ARE TO BE OUTPUT- IZSCAN NON-ZERO FOR Z-SCAN /PAGE ONE SET OF 6 PER LINE, END WITH ALL ZEROS
Nf"1m, IMR*rCH, TTwnshr. aqsgzpa, m ustn>
- + 1000 0 0.99 0 0
============================================
Now for the Source data -
Number of Sources = 49 ID# l ENERGY l INTENSITY l CHARGE 1 i 0.028 1 405,000 l -1 2 1 0.085 1 454.000 1 -1 3 l 0.142 l 486.000 1 -1 4 l 0.199 ! 502.000 l -1 5 l 0.256 1 504.000 1 -1 6 l 0.313 l 497.000 l -1 7 1 0.370 l 482.000 l -1 8 l 0.427 l 456.000 1 -1 9 I 0.484 l 423.000 l -1 10 1 0.541 1 384.000 1 -1 11 1 0.598 I 343.000 l -1 12 l 0.655 l 305.000 1 -1 13 l 0.712 l 273.000 l -1 14 1 0.769 1 249.000 l -1 15 l 0.826 l 228.000 l -1 16 l 0.883 1 208.000 1 -1 17 1 0.940 1 193.000 l -1 18 1 0.997 l 185.000 1 -1 19 l 1.054 1 184.000 1 -1 20 l 1.111 1 186.000 1 -1 21 l 1.168 l 186.000 1 -1 22 l 1.225 l 186.000 l -1 23 l 1.282 l 185.000 1 -1 24 l 1.339 l 183.000 l -1 25 l 1.396 l 180.000 l -1 26 l 1.453 1 176.000 1 -1 27 l 1.510 l 172.000 l -1 28 l 1.567 l 166.000 1 -1 29 1 1.624 l 160.000 1 -1 30 l 1.681 1 154.000 t -1 31 1 1.738 l 146.000 l -1 32 l 1.795 l 138.000 l -1 33 l 1.852 1 130.000 l -1 34 l 1.909 l 121.000 1 -1 35 j 1.966 l 112.000 1 -1 36 l 2.023 l 102.000 1 -1 l
37 1 2.079 l 93.000 1 -1 38 l 2.136 i 83.000 l -1 39 l 2.193 1 73.000 l -1 l 40 1 2.250 l 64.000 1 -1 l 41 l 2.307 1 54.000 l -1 42 l 2.364 1 45.000 1 -1 43 l 2.421 I 37.000 l -1 l 44 l 2.478 1 29.000 l -1 L 45 l 2.535 l 21.000 l -1 1
46 l 2.592 l 15.000 1 -1 47 l 2.649 I 9.000 1 -1 48 l 2.706 l 5.000 l -1 49 l 2.763 1 2.000 1 -1 Thu number of source lions = 49 SREG# { X LOW l X UF Y LOW l Y UPP l Z LOW l Z UPP l RHO l ID 1 0.000 12.0 0.000 12.000 0.000 0.500 1.00 1 2 0.000 12.000 0.000 12.000 0.000 0.500 1.00 2 3 0.000 12.000 0.000 12.000 0.000 0.500 1.00 3 4 0.000 12.000 0.000 12.000 0.000 0.500 1.00 4 5 0.000 12.000 0.000 12.000 0.000 6
0.500 1.00 5 0.000 12.000 0.000 12.000 0.000 0.500 1.00 6
.. - ~ _ . . - - . - - - -. - - _ - - - _ . . - ~ . - - ~ . - -
7 d . 0001 12.000 0.000 12.000' O.000 0.500 1.DD 7 B'- D.. DAD - .1.2 000 D.DDD A2 ade D.m D 509 .L.SS S
'9 -D.DDD- -32.DDD 0.DDD 32.DDD D..DDD D.5DS 2.98 9 10 0.000 12.000- 0.000. 12.000 0.0D0 0.500 1.00 19 11- 0.000 12.000 0.000 12.000 0.000 0.500 1.00 11 12- 0.000 -12.000 0.000: 12i000 0.000 0.500 1.00 12 13- 0.000 .12.000 0.000 12.000 0.000 0.500 1.00 13 14 0.000 12.000 0.000 12.000 0.000 0.500 1.00 14 15- 0.000 12.000 0.000 12.000 0.000 0.500 16 1.00 15 0.000 12.000 0.000 12.000 0.000 0.500 1.00 16 17 0.000 12.000 0.000 12.000 0.000 0.500 1.00 17
.18. 0.000 12.000 0.000 12.000 0.000 0.500 1.00 18 19 0.000 12.000 0.000 12.000 0.000 9.500 1.00 19 20 0.000 12.000 0.000 12.000 0.000 0.500 21- 0.000 1.00 20 12.000 0.000 12.000 0.000 0.500 1.00 21 22 0.000 12.000 0.000 12.000 0.000 0.500 1.00 22 i 23 0.000 12.000 0.000 12.000- 0.000 0.500 24 0.000 1.00 23 12.000 0.000 12.000 0.000 0.500 1.00 24
'25 0.000 -12.000 0.000 12.000 0.000 0.500 1.00 25 12 6 0.000 12.000 0.000 12.000 0.000 0.500 1.00 26 27- 0.000 12.000 0.000 12.000 0.000 0.500 28 0.000 12.000 1.00 27 0.000 12.000 0.000 0.500 1.00 28 29 0.000 12.000 0.000 12.000 0.000 0.500 30 1.00- 29 0.000 12.000 0.000 12.000 0.000 0.500 1.00 30
-31 0.000 12.000 -0.000 12.000 0.000 0.500 32 1.00 31 0.000 12.000 0.000 12.000 0.000 0.500 1.00 32-33 0.000 12.000 0.000 12.000 0.000 0.500 1.00 33
'34 0.000 12.000 0.000 12.000 0.000 0.500
- 35. 0.000 1.00 34 12.000- 0.000 12.000 0.000 0.500 1.00 35-36 0.000- 12.000 0.000 12.000 0.000 0.500
- 37. 0.000 1.00: 36 12.000 0.000 ~12.000 'O.000 0.500 1.00 37 38 0.000 12.000 -0.000 12.000 0.000- 0.500 39 '0.000 12.000 0.000 1.00 38' 12.000 0.000 0.500 1.00 39 40- 0.000~ 12.000- 0.000 12.000 0.000 0.500 41 1.00 40 0.000 12.000 0.000 12.000 0.000 .0.500 1.00 41-
- 42. 0.000 12.000 0.000 12.000 0.000 0.500 43- 0.000 1.00' 42 12.000 0.000 12.000 0.000 0.500 1.00 43 44 0.0001 12.000 0.000 12.000 -0.000.
45 0.500 1,00 14 4 0.000 12.000 0.000 12.000 0.000 0.500 1;00 45 46' 0.000 12.000 0.000 12.000 0.000 0.500 1.00 47 0.000 12.000 0.000 12.000- 0.000 '0.500 1.00 47 48 0.000 12.000 0.000 12.000 0.000- -0.500 1.00 -48' 49 O'.000 12.000 0.000 12.000 0.000 0.500 1.00 ~49 End of-the Source data :
Rcg: 1 Bnds (XYZ) = ( 0.000 12.000)( 0.000 12.000)(;
CPUTIME.SO FAR=
8i380 a 0.000 0.500)
' Rag: 2 Bnds (XYZ) = ( 0.000 12.000)(
p CPUTIME1SO FAR= 31.940 s 0.000 12.000)( 0.000 .0.500)
Rsg: 3 Bnds (XYZ) = ( 0.000 12.000)(
CPUTIME SO FAR= 79.640 s 0.000 12'.000)( 0.000 0.500)
Reg: 4 : Bnds (XYZ) = ( 0.000 12.000)( 0.000
-CPUTIME-SO FAR=- 141.130 s 12.000)(_ 0.000 0.500)
Reg: 5 Bnds;(XYZ) = ( -0.000 12.000)(
CPUTIME-SO FAR= 214.040 s 0.000 12.000)( 0.000- 0.500)_
Reg:
i CPUTIME'SO FAR=
. 6 ' Bnds (XYZ) = ( 0.000 12.000)( 0.000 12.000)( 0.000 0.600)
L 296.770-a Rsg: - 7 Bnds (XYZ) = (
- CPUTIME SO FAR=
0.000 12.000)( 0.000 12.000) ( 0.000 0.500) 1 388.450 s
.. . . - . - - ~ . - - - _ - - - . . - _ . --. .- . . - . - - _ . .
Rsg:- '30 -Bnds (XYZ) = ( 0.000' 12.000) ( 0.000 12.000) ( 0.'DDD -
CPUTDdE ,$D E.Abe .432$.dSD .c 4 5A04 Rsg:' 31 Bnds (XT2) = ( 0.000 -12.000)( 0.000
-CPUTIME'SO FAR=- -
5000.520 s 12.000)( 0.000 0.32t).
.- Reg : - 32 Bnds 'XYZ) = ( 0.000 12.'000)( 0.000 12.000)( 0.000
-CPUTIME SO FAR= 5284.130 s 0.500)
Reg: 33 Bnds (XYZ) = ( . -0.000 12.000)(. 0.000 12.000)( 0.000 CPUTIME SO FAR= 5573.400 s 0.500)
Reg: 34- Bnds (XYZ) = ( 0.000 12.000)( 0.000 12.000)( 0.000
- CPUTIME SO FAR= 5873.300 s 0.500)
-Reg: - 35 Bnds (XYZ) = ( 0.000 12.000)( 0.000 12.000) ( 0.000 0.500)-
CPUTIME SO FAR= 6178.250 s ,
. Rsg:. 3 6 Bnds (XYZ) = ( - 0.000 12.000)( 0.000 12.000)( 0.000 CPUTIME SO FAR= 6486.600 s 0.500)
Reg: ~ 37 Bnds (XYZ) = ( 'O.000 12.000)( -0.000 12.000)( 0.000 CPUTIME SO FAR= 6800.400 s 0.500)
Reg: 38 Bnds (XYZ) = ( 03000 12.000)( 0.000 112,'000) (
CPUTIME SO-FAR= 0.000 0.500) 7130.080 s
. Reg: 39 Bnds (XYZ) = ( 0.000 12.000)(
CPUTIME.SO FAR=- 7458.410 s 0.000 12.000)( 0.000 0.500)
Rag: -40 Bnds_(XYZ) = ( 9.000 12.000)( 0.000 12.000)(
rCPUTIME=SO-FAR= 7798.110 s 0.000 0.500)
.1 Rsg:' 41 Bnds (XYZ) = ( 0.000 12.000)( 0.000 12.000)(
CPUTIME S0 FAR= 8144.020 s. 0.000 0.500)'
Rsg: 42 Bnds (XYZ) = ( 0.000 12.000)(
CPUTIME SO FAR=: 8499.689 s 0.000 12.000)( 0.000; 0.500)
Rag:- --4 3- Bnds (XYZ) = ( 0.000 0.000 12.000)( 0.000 CPUTIME SO:FAR= 8859.131 s. -12.000)( 0.500)
- Rog:- -4 4 Bnds (XYZ) = ( ;0.000 -12.000)( O'.000-
,CPUTIME SO FAR= :9228,939's 12.000)'( 0.000 0.500)
-Rag: 45 Bnds (XYZ) = ( 0.-000
'CPUTIME SO FAR=
12.000)( 0.000 12.000)( 0.000 0.500) 9598.320 s R Rag: - - 4 6 Bnds (XYZ) = ( 0.000 12.000)(
CPUTIME SO FAR=- -9967.'270 s 0.000 12.000)( 0.000 ;0.500)
. Reg: 4 7 .Bnds (XYZ) = ( 0.000 12.000)( 0.000 12.000)(- 0.000-FCPUTIME'S0-FAR= -10352.180 s 0.500)'
.JRsg: 4 8.- Bnds (XYZ) = (- 0.000 12,000)(
CPUTIME SO FAR= 10743.280 s 0.000 12.000).( 0.000 - _0.500) ,
i Rag : . 4 9 Bn'ds (XYZ) = ( - 0.000-CPUTIME.SO FAR= 11136.439 s
- 12. 0 0 0) -( - 0.000- 12.000)( 0.000 0.500)
-0 TOTAL CPUTIME FOR SIMULATIONS = 402.7 s =
0.112 hr TOTAL' ENERGY DEPOSITED IN VOLUME per DECAY = 0. 8 0'73E+0 0 v'
g
% .Ae ~a m&
d 'T cngy,a.e M
.1-! The dame to inq czabe af e quessement matta a my-66 eneuman-p
_ XY (VOI) DOSE OUTPUTS Gy/ Disintegration FOR X= 2.000 TO 10.000 -I= 2 OYBOUNDS: 2.000 10.000 J= 2 SBOUNDS ( 0.000)
~D.100 1 2.089E 1.4%
- 0.200- 2 2.329E 2.2%
-0.300 3 2.292E 1.8%
0.400 4 2.397E 1.7%
-0.410 5 2.292E 3.2%
0.420 6 2.336E 3.9%
C_ 0.430 7- 2.207E 2.4%
r'
-0.440- 8 2.262E 4.6%
'O.450 9 2.181E 3.5%
0 460 10 2 .13 0 E - l'3 - 3.5%
0.470 11 2'.179E 4.4% .
0.480 12 .2.005E 3.6%
0.490 13 1.842E 3.5% _
0.500 14 1_3'7E 1 c1 -. . . ap.
TU.510 15 Q.190E 6.3%1 . N 'I ;< !C ' I ".
'0,520 16 -1.119E 7.1%
0.530' 17 '1.017E 5.6%
0.540-J18 9.545E 6.4%
_l0.550 19 8.945E 5.6%
10.560 20 8.297E 7.7%
f-0.570 21 -7.429E 4 . 2 0J y)gf0.580 22 6.767E 7.4%
(0.590 23 6.458E '6,9%
'0.600- 24- 6 " A 4P-14 7.11 -,
): "' e ? .
- a a O.610 2 5. 'QE 8,Q ).? N/7
- 0.620 ' 26- 5.750E 7.2%
- 0.630 27- 5.258E 8.3%
i-28 5.470E 7.3%
L , 0. 0.640 650 . 29 4'939E 7.6%
j0.660 30~ 4.703E 8.2%
1 1 0.670- 31 4.712E 7.7%
' O.680- 32' 4.263E-14 8.7%
' O.690 _ 33 ,L117E-14 -: 7. 3_%_
- 0.700 34 -(4.114E 6.90 #
q erd 6 / /#'b ' - )
., 0.800 35 2.998E-14 .5.8% D . g
), 7 O ,
p 0.-900 36' 1.833E-14--9.7%
- 1.000 1 37 9.706E-15-15.3%
1.100- 38 4.820E-15-12.0%
1.200 39 '1.730E-15-22.7%
, 1.300 ' 40 7.569E-16-26.0%.
1.400 ' 41 4.322E-16-30.5%
1.500 42 1.410E-16-40.1%
1 600 43 6.851E-17-64.2%
1.700. 44 4.368E-17-81.8%
1.800 45 8.024E-17-58.8%
1.900 46 1. -7 8 6E- 1. - 5 7 .1 %
w 2.000. 47 7.528E-17-73.6%
y 8
-2.100 48 3,085E-16-56.0%
- 2.200 49 2.4 73is-Af-fL.28 2.3DD SD 1. DD4E-16-96.4 % ,
2.400 51 1.452E-16-85.0%
2.500 52 1.463E-17-99.9%
l l
1
. les J hrsasos per@rroad #tes, bei At 3,k asuhKW Jh we
.a. se es Me .
e Technical hmorations and Notes
. MONTE CARLO AND CONVOLUTION DOSIMETRY FOR STEREOT (CFIC RADIOSURGERY SilRIKANT S. KUnsAD hl.S., T. ROCI .WELL M ACKIE. Pil.D.. M ARK A. GEliRINC. B.S..
DAVID J. MisiscO. M.S.. BliUDATT R. PAUWAL, Pfl.D. MINESil P. MEllTA, M.D.
AND TIMOTIIY J. KINsELLA. M.D.
Depanments of Iluman Oncology and Medical Physics. University of Wisconsin Medical School. Madison. WI 53792 USA The dosimetry of small photon beams used for stern.::"eic radiosurgery was irnestigated using Monte Carlo simulation, convolution calculations. and measurements. A Monte Oirlo code was used to simulate radiation transport Ihrough a linear accelerator to produce and score energy spectrum and a .vilar distribution of 6 M V bremsstrahlung photons niting from the accelerator treatment head. These photora were ti.*n transported through a stereotactic collimator system and into a water phantnm placed at isocenter, the energy spectrum was also used as input for the convolution method of photon dose calculation, Monte Carlo and convolution results were compared with the measured data obtained using an ionization chamber, a diode, and film.
Monte Carlo, Convolution, Small beam photon dosimetry, Stereotactic radiosurgery.
INTRODUCTION radiation therapy and are cost-cifective. The use ofa linear accelerator for stereotactic radiosurgery and its advantages -i Stereotactic external beam radiosurgery was initiated by over other approaches have been discussed elsewhere (3, Leksell in Sweden in 1951 (15.16). Since then, radiosur- 8. 9.10.17, 26, 31 ). Since stereotactic radiosurgery delivers gery has been performed with X rays. protons. heavy high doses of radiation in a single fraction to a small target charged particles, and gamma rays. The method involves volume (the radiation held sizes are typically from 0.5 delivery of a high radiation dose in a single fraction to a em to 4.0 cm in diameteri, accurate dosimetry and mt-small intracranial target. Leksell's work led to the devel- ment planning are entical to the adaption of a linear ac-opment of the commercially available Gamma Knife unit celerator for radiosurgery. ..
which consists of 201 *"Co wray sources. The Gamma There are two principal concerns in the dosimetry of Knife has been widely used to treat arteriovenous mal- small beams: the presence oflateral electronic disequilib.
formations and brain neoplasms. Using a proton beam, rium and steep dose profiles. lon chambers cannot predict .
Kjellberg et al. have treated and followed several patients with sufficient resolution the dose in the penumbra which, with afteriovenous malformations and have analyzed the for the smallest held sizes, extends to 'he central axis of . "
post-treatment cure and complications 111,12). They also the held. Radiographic him and diode can provide better.
established a correlation between dose and beam diameter spatial resolution but the film has a resp anse which varies to predict post treatment complications. with photon energy more than that o 'an ion chamber -
Recent developments have led to the conversion oflin- and a well shielded diode. The energy rr sponse etTect could car accelerators into stereotactic tools. The use of a linear be signi6 cant in broad beam photor dosimetry because accelerator for radiosurgery is gaining popularity over the . of the variation in the photon eneegy from the central
- Gamma Knife mainly because linear accelerators are axis to the edge of the neld. This variation in the photon available in most medical centers practicing conventional '
energy across the field is caused by the flattening ftlter jl l
l Presented at the 31st Annual ASTRO Meeting. 5 October Reckwerdt for his help in computations, Wonho Sohn for his 1989, San Francisco, CA. assistance in measurements. and Drs. David W. O. Rogers and
= Reprint requests to: Shrikant S. Kubsad. M.S., Department Alex F. Bielajew for their valuable discussions on MW.te Carlo of fluman Oncology, K4/B100 Clinical Science Center. 600 methods. The first author is also grateful to Drs. Claudio ti.
flighland Ave., Madison WI $3792 USA. Sibata and Paul M. DeLuca. Jr., who introduced him to the
.4cknowledgemenn-The authors wish to thank Terry Cum- Monte Carlo methods. This work was partially supported by mings of Varian Associates for providing the design specifications NCI grant R29 CA48902.
of the Clinac-2500 linear accelerator treatment head. Paul Accepted for publication 26 Apnl 1990.
1027
1028 J J Emun OncologyO Baolo C Pbmes hher 1990. Volume 19. Mmccr 4 which hardens therhoton beam more in the central pan "The code follows each particle and its prtwtry tmtilit of the beam than in the penpheral region (22). However. escapes or its energy falls below a cut off energy set by in a small beam the photon energy vanation across the the user to terminate the transport of that particle and beam diameter can be negligible. deposit its remaining energy on the spot.
The Alonte Carlo and convolution methods can be used The schematics of a typical LATH geometry are shown to produce relative dose distributions free of energy re- in Figure la. whereas Figure Ib illustrates the simulated sponse artifacts and equivalent to the resolution of diodes LATH geometry used in hionte Carlo method. The di-and tilm isodensitometers (l to 2 mm), but in order to mensions and distances of the LATH were obtained from do this. information such as the energy and angular spec- the sendor and were venfied during a major servicing of trum of the incident photon beam is required. The N1onte the machine. The pnmarv. secondary, and stereotactic Carlo method is used to produce such information and collimators and moving jaws were Jimulated using con-to senf> the accuracy of the nlm and diode measurements. centne cylindrical slabs. The thkkness and radius of each slab were carefully chosen to have the same surface area as the actual LATH and to reproduce the divergence of NIETilODS AND MATERIALS the radiation beam. The simulation used a series of cy-t/ome ( ~arlo method lindncal slabs stacked on one another to match closely We used the Electron Gamma Shower Version 4 the probie of the Gattenmg filter. We simulated both the (EGS4)(23) N1onte Carlo code system to charactenze the upper and lower movmg jaws at the same level. The ste-photon beam emerging from the accelerator treatment reotactic collimators were lead-blled cylinders of 15 cm head. The energy spectrum of photons was used to pro- in height with divertaing circular holes of 0,5 cm to 4.0 duce a dose kernel for the stereotactic beam from mono- em m diameter, and were attached to the linear accelerator energetic photon beam kernels generated in water (19). head.
The EGS4 N1onte Carlo code is a general purpose coupled The SCS and stereotactic base frame that mounts on charged particle-photon transport simulation system that the accelerator couch base plate and other quality control can transport these particles in the energy range of a few accessones' were built to specihcations for our linear ac-lev to GeV in heterogeneous media of arbitrary 3-di- celerator.' We also oesigned and built a stereotactic mensional complex geometry (23). hiany authors have demonstrated that sery complex and sopiiisticated sim.
ulations can be done using hionte Carlo methods code ,, e m_ m %,,,n, (5.8.13.I4.22,24,25,27,29,10). , i t ...
We developed the user main program and geometry packages to simulate the linear accelerator
- treatment
""""r N ,"
h "
head (l.ATH). the stereotactic collimatmg system (SCS) g' I pAj *"'"'*"""'"'*'
t:::f , t:.::
d "
and a semiinfinite water phantom placed at the isocenter (source to-isocenter distance was 100 cm L The user main -
k "'"1",7"'
b -
s,,_
i program drives the geometry package and the EGS4 i
%C N 3 C
- ==" d
~
N1onte Carlo code to simulate particle transport using in- I I I~:
teraction probability distnbution data generated by Qii;@ !
PEGS 4 (Preprocessor for EGS4)(23). The user code sets @giWM[M@di[ld hjd?M I in motion photon histories (simulated photons) and q p;:';;;;
transports them until they are absorbed or scattered. The g jiiss gl j _hq ["L p~yl; y energy and direction of charged particles set in motion and scattered photons are determined by the EGS4 code ,b 3 system and subsequently transported as well. Cha ged I i
- seere== M Mif i Sa'=
1 particles are transported in discrete steps during which the particle ts assumed to travel a straight line: however.
l
=.-}
l y stu loa cunoe, h
the energy loss is scaled to account for increased path- ;
- i. W aer Punan :
length caused by scattering. The user code handles the I "$7 J)'
sconng (tabulation of results for a history) of one or any 'I l' combination of type of particle, energy, position, and 6- m m rection cosmes for photons and charged particles each Fig.1. (a) Schemaucs of the linear accelerator treatment head, time a particle n?eraction or boundary crossmg occurs. (b) Simulated linsar accelerator treatment head geometry used Sconng also occurs following each charged particle step. in Mome Carlo calculations.
- Clinae-2500. Vanan Jssociates, palo Alto. CA.
' physical Science Labeatory, Umversity of Wisconun.
Madison, WI. ;
1 l
l l
. . . ~ ~ - :.-. . ~ ~ ~ . . - . . . . _ _ -. __
t
. Monte Carlo and convolution dommetryOR 1 AMasaper ff
. au
$m*t=5 -twtM4 in tenm eOmio 180 9
'y:
collimator made of tungsten. The Gatten ECUT 5 0.521 MeV ,
prised of an alloy containing steel.nand other elements I jff .
. PCUT = 0.010 MeV addition to making the Quence distribution morr uniform.
the flattening hiter also produces low energ y electrons and ESTr.PE = tu of the electron-energy at the begmning of ~
"'" chamber and is subsequently shaped by collimators and moving tungsten jaws.
SMAX = Smallest dimensionWe scored the energy spectrum and angular distributi of 6 MV bremsstrahlung photonson in annular regions of .
NCASES = 2 x10*/
- 1. 2,3, and 4 cm in radius in a plane u target ar to perpendic l smutanon the central axis at 50 cm from thephoton .
The energy spectrum, For cach region ofinterest r photon energy, meanw planar duence, the an the fluence mean Quence the me -
a (STM) air ion chamber which was ,
- o monitor the radiation output. This 'weighted mean energy,eighted, and the energy Ouence sed to venfy the dose delivery to the '
incidence on the scoring plane with respect to theand the ph axis, were calculated in each energy central bin.
lation was carned out in two parts, mulated the accelerator head
>m of the movmgjaws to score the phantom.
from The stored spectrum was used to ,
laractenstics tenergy spectrum and the bottom of the movingjaws
- initial energy and direction of photonsrom e
transported f n a plane perpendicular to the cen-through the SCS and in a ,
.. characteristics were stored cylindrical forlater water phantom placed e at the isocenter (th
- part of the simulation starts from source to-surface distance of the phantom was 100 cm).
he movingjaws through the SCS, The movingjaws were included in the second part of th r
-antom at the isocenter, simulation to account for potentiale scatter from the bot ;
indationo/theLITH. Asdepicted tom of the jaws and also to maintain the conti nuity be-tic electrons with a kinetic energy gions, the mean energy depositiotween .
o t e re- the two parts of t the vacuum window of theence, ac- the pnoton mean energy,n, the photon mean uu.
and the photon mean ungsten target producing brems-
--beam passes through the backing incident angle with respect to thee cal- central axis wer c and gold alloy for fast heat dis- : was 0.2 cm in any direction ution, to ensure better re especially for beam probles in a water phantom /
~
- t. t 4.. I 1
.i.
]
1 i i
^
- l. ' ,
. . . .}.}
.sq'; -
c
[6 WY Photon Energy Spectrurn '
y -
' ECS4 - Wonte Catto Celeuietaen aadial Range = 044 cm at 50 cm from the target e
riuence w igMed Mean Energy *-192 a 004 WeV l - _ Energr41uence WeisMed Wenn Energy a W g LJ c e 2 76
- 0 07 WeV D
- 0. 1.
a__ 3 4
5 Photon Energy (kleV) 6 spectrum of 6 MV photons from the linear accel
! erator at 50 cm from the target.
1
,..-n - , . . - . , - . - . - . , .,.c _ .-,
- l
- 'i; j 1 '_ jj
-1030 -
L J,h Omaningwe Sanhed Mvencs Octohsr 1990. Volvar 19. Nuantsd -
--120 -
o WV Photons
.. D o em Dia. Cell 100 - ;
.-d--@c g -- o Wonte carte >
.)e-. - _ [g . .-_
.h 4 o convolutson
- 0. 80 k: 'l io3,i*4
( ro
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l'ig. 3. (a) Central axis depth dose in water for 0.5 cm beam diameter. (b) Central axis depth dose in water for 2 cm beam diameter. (c) Central axis depth dose in water for 2 cm beam diameter. (d) Central axis depth dose in water for 3 cm beam diameter.
EGS/ imnsport and calcidation parameters. The results inside the phantom and the kemel accounts for secondary of Monte Carlo simulations are verysensitive to transport - particle transport in the phantomi parameters such es the maxirnum relative energy lost in , The dose distribution D('r J in a homogeneous phantom an electron step (called ESTEPE in EGS4), the maximum - can be given by the equation:
electron step length (SMAX), the cler'fon cutoff energy
'(ECUT), and the photon cutotr energy (PCUT)(4,5.14. >
, 27/ 28. 29). Additionally, the total number of histories .
- y. .
- transported per simulation (NCASES) dictates the accu. Of f ) " , -(r')t(r.')A( r - I)d'r' (1)-
racy of the fmal results. Moreover, the random sampling ofincident particle's energy, position and direction cosines at the beginning of simulation directly affect the final out- where (p/p)(I) is the appropriate mass attenuation coef.
= come. The secondary electron production energy thresh- ficient distril lution, f(P ) is the energy fluence distribution, -
1 old ( AE)of 0.521 MeV and secondary photon production and A(r - r')is the convolution kernel.
energy threshold-(AP) of 0.01 MeV were used b the. _ The details of the convolution / superposition sotiware l t PEGS 4 to generate the interaction probability distribution ' have been described elsewhere (20). The superposition
~
adata for electron and photon transport.' The EGS4 used method involves modifying the convolution kernel to take
' the data produced by the PEGS 4 and also used the trans- into account transport through heterogeneous phantoms; port parameters shown in Table I to carry out the sim- '
however, this capability was not required in this study
. ulations. 'because the phantom was. homogeneous. The voxels were LThe particles were terminated when their energy fell solid rectangles (i.e.. the voxel dimensions may vary in (below the cut-off energy or escaped the simulation ge- each direction). The voxel thickness was 0.25 cm in all' i ometry. When particle termination occurred, the residual- of the calculations and the voxel areas were 0.1 X 0.1 cm 2=
- kinetic energy of the particle was deposited locally. for the 0.5 cm and 1.0 cm collimators and 0.2 X 0.2 cm2 -
l Each simulation of 2 million histories was divided into - for the larger collimators.
10 batches for statistical analysis. The standard error in . Most of the convolution / superposition softwareis con -
each scored quantity was determined from a calculation cerned with modelling the primary ene" + fluence distri-of one standard deviation from the 10 batches, bution. The software is capable of modehang the " horns" in the incident energy fluence distribution, spectral hard-Convolution method ening in the depth direction, and " softening" in the lateral A' number of authors have shown that the convolution -- direction mainly because ofa reduced thickness of primary -
of a primary intensity function and a spatially invariant rays that have travelled through the field flattening fdter.
kernel models the dose distribution well in a homogeneous The beam is first modelled as diverging from a point phantom (1, 2, 7,18.19, 20, 21). The primary intensity source and exiting through a perfect circular aperture with function models the primary photon transport up to and constant energy fluence across the field. The energy flu-i
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' 4. Ia) Beam prohle of 0.5 cm beam diameter at 5 cm depth in w u diameter at $ cm depth in water,em depth in water. (c) Beam pronte of 2 cm beam diamete epth in water. (d) Beam pronle of 3 cm imed to decrease exponentially (with distance ic phantom and with an inverse-square fall-side a field in routine external beam radiotherapy are from surfacc.
-:n by the following equation:
3 to 5'"o from the first two of the above components. How-ever, it was found that the secondary stereotactic colli-
,;, , .,,[
mators effectively reduced this component of the Guence SSD j2 to zero (10.1%). The geometrical penumbra can be ac -
- \SSD + d/
by Boyer (6). It involves specifying an etTectiv en e surface energy tluence, g,a is the etTective (s , taken to be 0.2 cm)and the source to-collimator dis -
.etftcient. and SSD is the source.to-surface tance (SCD) of 77 cm, which is the distance from the J
- source to the end of the stereotactic collimator. The model attenuation coetheient was obtained from assumes that a tinite source size can be modelled as a i coethcients weighted with respect to the .
convolution of the energy Quence with a 2-D Gaussian of the spectrum. We used the spectrum is work (illustrated in Fig. 2) and a pub- distance (SPD) equal to the following: distribution 1 from Mohan et al. (22). The etrective En 3 coetheient at the surface of the phantom
/g and 0.0481 cm /g for those spectra. FWHM = s,,SCDE (3)
- I model of energy fluence was modified The tinite voxel size introduces a blurring artifact
- r for primary energy Guence outside the(analogous to the finite size of a detector) that mimics a
- ic beim boundary. The primary Quence finite source size in its effects. Therefore, FWHM is re
? i consists.of sevemi components: trans- duced by an amount equal (i.e., either 0.1 cm or 0.2 cm).
to the lateral voxel dimension-S he collimators, photons scattered outside I the accelerator structure, and the colli.
cal penumbra due to a finite source size. Measurements i imiry" energy fluence should be quali-2 photon energy fluence which has not wi'h We used a small diode and a small ionizat.on a three-dimensional scanner in a water phantom to chamber
- the phintom regardless ofits origin in acquire depth doses and beam profiles.t
.pical values of the primary 11uence out- Film dosimetric measurements were carried out by exposing radiographic 8
verification films in a Solid Water Phatom.' The films
- tallered. Sweden.
seTek OY, Espoo. Finland, driven by HP NY. 8 Kodak X Omat V, Eastman Kodakochester, Company R dett.Packard Co., Fort Collins. CO. i Radiation Afeasurements Inc., htadison WI.
,; .(..
1034 ' II J. Radiadon Oncokyy C Biology 0 Phynes ' October 1990. Volume 19. Numter 4 i ' we7e ra trsms a Tupid prnt-nr.'*, A fdm scarmmg frtwn 1.38 to 1.75 cm. The decrease in the depth erf peak $ V' dsnsnometer." dnwn by a stepper motor comroller dose for smaller field sizes is causedkdetsummedemuni
- board"in a PC" and controlled by sc 'tware written using scatter contribution to the depth dose. I
-a data acquisition package,* was used to scan the pro- l cessed films to acquire depth doses and beam profiles. Relative beam pro /r/cs in water The. diameter of the isodensitometer light spot was 1.0 The relative beam profiles at a depth of 5 cm in water 0.2 mm. for beam diameters of 0.5.1,2,3. and 4 cm were com-puted using direct Monte Carlo and convolution calcu.
RESULTS lations using photon spectrum from the present work and the published spectrum (22L Comparisons of the calcu-Energy spectroms and angular distrihmion lated and measured data for beam diameters of 0.5,2, The energy spectrum of 6 M V bremsstrahlung photons and 3 cm are shown Figure 4. Again, there is excellent from.the linear accelerator is shown in Figure 2. At 50 agreement between the profiles obtained by Monte Carlo em from the target, the fluence and energy-Ouence and convolution calculations, and film dosimetry. The weighted photon energies at the central axis (within radial disagreement between Monte Carlo and convolution re-range between 0 to i cml wen: 1.92 0.04 and 2.76 0.07 sults in the beam boundary region can be reduced if the :
MeV respectively. The Quence and energy-Huence size of the scoring regions are further decreased below 0.2 !
weighted photon mean incident angles with respect to the . em in the radial direction in calculational methods but central aus were 1.61 : 0.08 and I;21 0.05 degrees. at the expense of increased computing time for Monte respecuvely. Carlo calculation. There is excellent agreement outside the primary beam because appropnate penumbral cor-Central uxt3 tc/arire depth doses in water rections have been employed in the envolution calcu.
Ihe relauve percent depth doses in water for beam di- lations Note that the uncertainty has decreased radially ameters of 0.5.1. 2. 3 and 4 cm were computed usmg outwarci because the volume of scoring regions (volume L direct Monte Carlo simulation and convolution calcula' = rr h) increases as a function of radius to the power
- tions using photon spectrum from the present work and two, thereby resulting in a larger number of histories in
'a published spectrum (22). Comparisons with the mea- those regions.
sured data for beam diameters of 0.5. 2. and 3 cm are shown in Figure 3. There is excellent agreement between Computation times the results of Monte Carlo, convolution calculations and
- diode measuremems beyond the depth of peak dose. We used a workstation * (a5 times faster than a mini
,,) g 3; g g g
% ithm the build up region for 2 and 3 cm beam diameters, lation used 120 CPU hours to transport 2 million initial
?the results of Monte Carlo and convolution calculations electron histories through the linear accelerator head to agree with the diode measuremerits withm 2% and 5%.
obtain the photon energy spectrum and other character-respectisely The depth doses for beam diameters of 0.5 istics, whereas the same number ofinitial photon spectral
-to 4 cm, denved by Monte Carlo and convolution meth-histories transported in water to obtain depth doses and ods, are in excellent agreement beyond the depth of peak beam protiles required an average of 80 CPU hr per beam dose, but m the build up region a disagreement of 2 t
, diameter. The average computing time for the convolution 10% is observed. This may be because the low energy calculations was 0.06 CPU hr per simulation on the same
- scattered photons and electrons arising from the SCS are "YSI" *
- not accounted for in the convolution calculations. The depth doses derived by convolution method using the photon spectrum produced in this work and the published DISCUSSION spectrum from Mohan et al. (22) agree within 3%. The Emeasured depth dose by diode and depth ionization by We have shown that the Monte Carlo method can be ,
ion chamber measurements are in good agreement for used to characterize the 6MV bremsstrahlung photon.
large beam diameter (23 cm) as shown in Figure 3d. beam produced by the linear accelerator and to obtain whereas' increased disagreement is observed as the beam- - the dosimetric for small radiation fields used in stereotactie
- diameter is decreased. This could be because of the larger radiosurgery. We found that the simulation of exact di-size of the ion chamber in a small radiation beam. The mensions of target, backing material, and Hattening filter. .i
- depth of peak dose for 0.5 to 4 cm beam diameters ranged 'and appropriate Monte Carlo transport parameters were
" Kodak RP X:Omat rapid processor. Eastman Kodak "' ASYST. Asyst Software Technologies Inc., Rochester.
- Company, Rochester, NY, NY.
" Artronix. St. Louis. MO.
- Sun 4/110. Sun Microsystems Inc.. Mountain View, CA-H METRABYTE, Metrabyte Corporation, Taunton, MA. ' VAX 11/780, Digital Equipment Corporation, Maryland, H Leading Edge PC. Leading Edge Products Inc., Needham MA. ,
Heights. MA.
_ _.___ . _ _ -._._ _ , _ __ _ _ _ _ _ - . . . . ~ . _ . _ _ _ _ __
0 '%
Monte Carlo and convolution dosametry 0 S. S. KtzAD ri al. 1035 nuwbut in setturrmt securate photon energy tperTra We have dewloped m-house a sterectaenc'nesunewt imd tmgular distffbutions. Our user wntten prognmunam planning system which uses the dosimeme thentuisium-be generalized to simulate other treatment machines to erated by the convolution method. The simulation ofthe obtain beam and dosimetne data. Similarly, we have accelerator treatment head by the Monte Carlo method shown that the convolution techniques using Monte was required to obtain the energy spectra used for the Carlo-produced photon energy spectra can calculate do- convolution method and to provide a clarification ofits simetric data used for sterectacic radiosurgery. The results dose predictions independent of measurements.-In sum-of Monte Carlo and convolution methods are in excellent mary, we have demonstrated that the Monte Carlo and agreement with the measured data. The spatial resolution convolution methods are powerful and practical tools to or Monte Carlo and convolution methods were adequate generate accurate dosimetric data. These methods can be-and comparable to film and diodes for use in small beam come the basis for dose computation in the routine clinical dosimetry, treatment planning algorithms using fast computers.
REFERENCES
- 1. Ahnesio, A. Collapsed cone convoluuori of radiant energy 15. Leksell. L. Stereotaxis method and radiosurgery of the bram.
for photon dose calculation in heteroger.cous media. Med. Acta Chir. Scand. 102:316-319: 1951.
Phys.16:577-592:1989. 16. Leksell L. Stereotactic radiosurgery. J. Neurol Neurosurg.
- 2. Ahnesjo. A.: Andreo. Pa Bmhme. A. Calculation and ap- Physiat. 46:797-803; 1983.
plication of point spread functions for treatment planning 17. Lutz. Wa Winston K. Ra Maleki. N. A system for stereo-with high energy photon beams. Acta Oncol. 26:49-57 tactic radiosurgery with a lmear accelerator. Int. J. Radiat.
1987; Oncol. Biol Phys.14:373-381:1988.
t Betti O. Da Munan. Ca Rosier, R. Stereotactic radiosurgerv 18. Mackie. T. Ra Ahnesid. Aa Dickof Pa Snider A. Devel-with the hnear accelerator; treatment of artenovenous mal- opment of convolution / superposition method for photon formations. Neurosurgery 24:311-321:1989. beams. Proceedmgs of IX* ICCR. International Conference
- a. Bielajew. A. F.: Rogers, D. W. O. PRESTA-The Parameter on Computers in Radiation Therapy, Den Flaag, The Neth, Reduced Electron Step Transport Algonthm for electron erlands. 1987:107-110.
Monte Carlo transport. Nucl. Instr. Meth, B18:165-181: 19. Mackie. T. Ra Bielajew. A. Fa Rogers, D. W. OJ Battista.
1987 J. J. Generation of energy deposition kernels using the EGS
- 5. Bielajew. A, Fa Rogen, D. W, Oa Nahum, A. E. The Mon? Monte Carlo code. Phys. Med. Biot 33:1-20: 1988.
Carlo simulation of ion chamber respon.. io "Co-reso- 20. Mackie, T. R.; Senmger.J. Wa Battista. J. J. A convolution lution of anomalies associated with interfaces. Phys. Med. method of calculating dose for 15 MV x rays. Med. Phys.
Biol. 30.419-427: 1985. 12:188-196: 1985.
- 6. Boyer, A. Founer convolution techniques. Proceedings of 21. Mohan, Ra Chui. Ca Lidofsky, L. Differetitial pencil beam the Regma Workshop on Convolution. Regina Canada, dose computation model for photons. Med. Phys.13:64-October 16-17.1986. 73:1986.
- 7. Boyer. Aa Mok, E. A photon dose distnbution model em- 22. Mohan Ra Chui. Ca Lidofsky. L. Energy and angular dis-
-ploying convolution calculations. Med. Phys. 12:169-177: tnbutions from medical linear accelerators. Med. Phys.12:
1985. 592-597:1985.
- 8. Colombo Fa Benedetti. A.: Pozza. Fa Avanzo. R. C4 Mar. 23. Nelson. W. Ra Hirayama. Ila Rogers. D. W. O. The EGS4 chettic. CJ Chierego, Ga Zanardo. A. External stereotactic Code System. Stanford Linear Accelerator Report SLAC.
irradiation by knear accelerator. Neurosurgery 16:154-159: 265:1985.
1985. 24. Petti. P. La Goodman. M. Sa Gabriel, T, A4 Mohan. R.
- 9. Colombo Fa Benedetti, Aa Pozza. Fa Zanardo. Aa Avanzo, investigation of build up dose from electron contaminatior' R. Ca Chierego, G.; Marchetti C. Stereotactic radiosurgery of clinical photon beams. Med. Phys. 10:18-24; 1983, utihzing a linear accelerator. Appl Neurophysiol 48:133- 25. Petti. P. La Goodman. M. S.: Sisterson, J. M4 Biggs, P. Ja 145.1985. Gabnel. T. Aa Mohan, R. Source of electron contamination
- 10. tiartmann. G. lia Schlegel, W.: Strum. Va Kober, Ba Pastyr, for the Clinac 35 25 MV photon beam. Med. Phys.10:856-
- Oa Lorenz, W. J. Cerebral radiation surgery using moving 861: 1983.
. f cid irradiation at a linear accelerator facility. Int. J. Radiat. 26. Rice, R. Ka llansen, J. L: Svensson, G. K. . Siddon, R. L Oncol Biol Phys. I1:1185-1192: 1985. Measurements of dose distributions in srcall beams of 6
- 11. Kjellberg, R. Na Davis, K. R4 Lyson. Sa Butler. Wa Adams. MV x rays. Phys. Med. Biol. 32:1087-10c 9: 1987.
R. D. Bragg peak proton thempy for arteriovenous malfor. 27. Rogers. D. W. O. Low energy electron trrnsport with EGS.
mations of the brain. Clin Neurosurgery 31:248-290;1984. Nucl. Instr. Meth. A227:535-548: 1984
- 28. Rogers, D. W. O. More realistic Mont; Carlo calculations
- 12. Kjellberg. R. N.: llanamura. Ta Davis. K. Ra L> son. S.; ,
Ut Adams, R. D. Bragg peak proton therapy for artenovenous malformations of the brain. N. Engt J. Med. 309:269-274:
9 33l 548: '
- 29. Rogers. D. W. Oa Ewart. G. Ma Kelajew, A. F. Calculation I983* ofcontamination of the "Co beam from an AECL therapy
- 13. Kubsad. S. Sa Mackie. T. Ra Paliwal B Ra Atttx, F. II. source. National Research Council of Canada Report No.
Monte Carlo calculation of electron and secondary photon PXNR 2710,1985.
spectra from a Varian Clinac.2500. Med. Phys. 16:49:1989 30. Udale, M. A Monte Carlo investigation of surface doses for (AbstrL broad electron beams. Phys. Med. Biol. 33:939-954; 1988.
I 14. Kubsad, S. Sa Paliwal, B. Ra Sibata. C. fia Attix. F.11. lon 31. Winston, K. Ra Lutz, W. Linear accelerator as a neuro-chamber electron Buence corrections for electron beams surgical tool for stereotactic radiosurgery. Neurosurgery 22:
(AbstrL Med. Phys.13:605: 1986. 454-464: 1988.
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