ML20247D101
| ML20247D101 | |
| Person / Time | |
|---|---|
| Issue date: | 11/06/1991 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20247D107 | List: |
| References | |
| SSD, NUDOCS 9805140270 | |
| Download: ML20247D101 (11) | |
Text
. _ _ - _ - - _
l REGISTRY OF RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE N O V 0 6 lS$ l NO, NR-687-D-107-S DATE:
PAGE 1 OF 8 DEVICE TYPE:
Total Body Irradiator MODEL:
Theratron 780-19 MANUFACTURER / DISTRIBUTOR:
Theratronics International, Ltd.
413 March Road P. O.
Box 13140 Kanata, Ontario, Canada K2K 2B7 SEALED SOURCE MODEL DESIGNATION:
Theratronics Models C-146 or C-151 ISOTOPE:
MAXIMUM ACTIVITY:
Cobalt-60 13,400 curies
- 15,000 curies **
Depleted Uranium 113 kilograms or approximately 250 pounds LEAK TEST FREOUENCY:
6 Months PRINCIPAL USE:
(C) Medical Teletherapy CUSTOM DEVICE:
X YES NO CUSTOM USER:
Harper Hospital Division Gershenson Radiation Oncology Ctr.
3990 John R Street Detroit, MI 48201-22197
- Lead Source Drawer
- 15,000 curies with a source output of about 13,400 Rhm when used with the optional source drawer Models G9-140, G22-140 and G22-140A.
9805140270 911106 PDR RC PDR SSD
O O
REGISTRY OF-RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE HQti NR-687-D-107-S DATE: NOV 0 61991 PAGE 2 OF 8 DEVICE TYPE:
Total Body Irradiator j
DESCRIPTION:
The Model Theratron 780-19 is the Model Theratron 780, serial
- 19 teletherapy. unit which has been modified to become a dedicated total body irradiator (TBI).
Theratron 780 rotational teletherapy units are equipped with the head and counterweight on a
"C" arm which normally rotates about the patient.
- However, this device will only be operated in the fixed mode with the beam pointing directly down (;t 5*).
Likewise, the source-to-skin distance (SSD) will be fixed at 150 cm (59") with the patient in the prone or supine position.
Rotation of the "C" arm and the head will be prevented by two mercury switches which will switch off the machine when rotated past 5'
from vertical.
For this i
reason the units functions are limited to moving the source to the "ON" or "OFF" positions with the exception of rotation of the 4
gantry which will take place approximately once every five years for source replacement and unit inspection.
During scarce replacements or unit inspections the limit switches may be temporarily bypassed, i
The device normally uses a Theratronics' Model C-146 or C-151 i
sealed source.
The sourcehead is designed to incorporate sources with outputs up to 12,000 Rhm and maximum activity of 13.4 kCi for sources containing pellets.
Alternatively, sources with outputs of up to 13,400 Rhm and maximum activity 'f 15,000 kCi can be-used with an optional source drawer containing an 8" (or I
8.5") uranium alloy (alloyed with 8 percent molybdenum and weighing 26-1/2 lbs; Model G9-140 or G22-140) or tungsten insert (Model G22-140A).
The sourcehead assembly consists of a lead-filled, cast steel shell_44-1/4 inches long x 21 inches high x 24-1/4 inches wide secured to the arm by means of a rectangular steel casting.
An unalloyed, depleted uranium billet is located within the sourcehead as part of the shielding for the "OFF" position.
A 2-1/2 inch diameter x 21-1/2 inch long brass encased, lead-filled source drawer moves horizontally through a distance.of 13 inches in 1-1/2 seconds by a pneumatic system linked to the source drawer.
Alternatively, a uranium filled source drawer (G9-140 or G22-140) or tungsten filled source drawer (Model G22-140A) may be used.
e t
_a
O O
REGISTRY OF RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE NO.: NR-687-D-107-S DATE: NOV 0 61991 PAGE 3 OF 8 DEVICE TYPE:
Total Body Irradiator DESCRIPTION: (Cont'd)
The teletherapy source is held in the source drawer by a source sleeve, tungsten or depleted uranium plus 8% molybdenum alloy plug and a retaining ring.
Lights in the sourcehead and on the control panel indicate the "ON" and "OFF" positions.
A fluorescent red-tipped rod extends approximately 5 inches through the front end of the unit top head cover and mechanically indicates the source position.
The source drawer retracts to the "OFF" position when the pneumatic pressure drops, power fails, or the treatment room door is opened; the unit must then be reset at the control panel to continue treatment.
Alarms on the unit (bell or buzzer) and at the control console (high frequency tone) sound off when the unit is first turned on or if an emergency pushbutton is depressed.
In an emergency, the source drawer can be mechanically pushed to the "OFF" position by use of an emergency T-bar.
Modification of the device was performed by Theratronics International, Ltd., and was accomplished by the following:
1.
Removal of the beamstopper and replacement with a counterweight.
2.
Removal and disposal of the adjustable collimator assembly and replacement with a non-adjustable collimator to provide a beam angle of approximately 75' (see attachment 2).
3.
Readjustment of the mercury switches to limit operation to the downward position (i 5').
4.
Electrical disconnection of the gantry and yoke motors to prevent rotation of the unit.
5.
Installation of a-steel flattening filter to improve beam uniformity'and reduce electron contamination and a microswitch to prevent unit operation when the filter is not installed (see attachment 3).
6.
Use of a redesigned treatment couch with a block mounting tray assembly for treatment of patients close to floor level.
1
O O
REGISTRY OF RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE i
NOV 0 61991 NO.: NR-687-D-107-S DATE:
PAGE 4 or s 1
DEVICE TYPE:
Total Body Irradiator DESCRIPTION: (Cont'd)
The new non-adjustable collimator was designed to fit into the head in place of the adjustable collimator.
It is constructed of molded CEREBEND (Lipowitz's metal) and weighs approximately 68 kg (151 lbs).
The collimator and flattening filter frame combined weigh approximately 90 kg (198 lbs) and are attached to the head with 6 bolts.
The collimator provides a rectangular field of approximately 185 cm in length by 75 cm in width (73" X 30") at an SSD of 150 cm (59").
It also reduces scatter radiation and alleviates the need for additional wall shielding.
Floor shielding does not need to be increased since the unit is located on the lowest level of the hospital.
The flattening filter is constructed of steel, 8" wide by 17" long and 0.68" thick at beam center tapering off to the ends.
It provides a more uniform beam distribution and reduces electron contamination.
The filter is held-in place by a frame and slide rail assembly which is bolted to the non-adjustable collimator.
The filter can be moved out of the path of the beam defining light along the slide rail in order to allow positioning of the patient.
A microswitch interlock is installed which prevents the source from being moved to the "ON" positicn when the filter is not fully installed.
Therefore, the filter must be returned to the fully installed position before treatment can begin.
Operation of the unit can be accomplished from either a hand control located near the unit or a control console located outside the treatment room.
The source drawer assembly is pneumatically operated while the gantry is motor operated.
The pneumatic system is designed through the use of relays, solenoids, valves, and sensing switches so that the drawer automatically retracts to the "OFF" position in the event of power failure or loss of pressure.
The device may contain uranium shielding as follows:
Sourcehead Billet (Unalloyed depleted U-238) 203 lbs.
Sourcehead Primary Definer (unalloyed depleted U-238) 17 lbs.
Round Uranium Source Drawer (U-238 alloyed with 8% molybdenum) 27 lbs.
250 lbs. max.
O o
REGISTRY OF RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE NOV 0 61991 NO.: NR-687-0-107-S DATE:
PAGE 5 OF 8 l
DEVICE TYPE:
Total Body Irradiator l
L DIAGRAMS:
l See Attachments 1, 2 and 3.
l LABELING:
Labeling for the de'; ice has net been modified and designates the unit as Model Theratron 780 serial # 19.
No labels were added or removed as a result of the modification.
Each source holder is identified by stamped characters 0.09 in.
i high x 0.01 in. maximum depth with the pertinent source drawer l
serial number.
The drawer is also identified on both end faces in characters 0.09 in. high x 0.01 in. deep with the inscription l
" CAUTION-RADIOACTIVE MATERIAL-URANIUM".
The source housing is labeled in accordance with 10 CFR 20.203.
CONDITIONS OF NORMAL USE:
The device is designed for use in a hospital or clinic l
environment for TBI treatment of patients with cancer.
l Conditions of use include a clean but not sterile area, conditioned air and adequate lighting and ventilation.
Shielding in the form of poured concrete or lead is typically used to surround the treatment area.
Considering the shielded room environment in which the device is used, the probability of severe conditions including accidents and fires is small.
EXTERNAL RADIATION LEVELS:
l The manufacturer has determined that the head can be loaded with up to 13.4 kCi of co-60 (output of 12,000 Rhm) with a normal source drawer or approximately 15.0 kCi (output of 13,400 Rhm)
'with a steel encased source drawer containing uranium shielding.
The average dose rate readings taken from points around a typical Theratron 780 unit do not exceed 2 Rhm with no points exceeding 10 Rhm.
The maximum activity source to be installed in this unit is not expected to-exceed 7,500 Ci.
For this reason the averago dose rates for the device are expected to be below those for a j
typical Theratron 780 loaded with maximum activity.
The only variation in measured radiation levels is expected to occur in
- beam, i
i
l.
REGISTRY OF RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE NO.; NR-687-D-107-S DATE: NOV 0 61991 PAGE 6 OF 8 DEyJCE TYPE:
Total Body Irradiator PROTOTYPE TESTING:
Model Theratron 780 teletherapy units have been in service for over 19 years.
A similar modification as described above has been performed on a Model Theratron 80 teletherapy unit at the University of Iowa College of Medicine with no significant problems.
Since the modification effects only the adjustable collimator leaving the rest of the unit intact, the past history of the The atron 780 series is accepteble for prototype testing.
QUALITY ASSURANCE AND CONTROL:
The Theratron 780 was manufactured within the guidelines of Theratronics International Limited's Quality Assurance and Control Program.
This program has been previously deemed acceptable by the NRC.
Harper Hospital will ensure the device is initially leak tested, tested for proper operation of the source exposure mechanism and safety warning components, correctly labeled and ensure external radiation surveys (source exposed, source shielded) are performed by the manufacturer or other persons specifically licensed by the NRC or an agreement State.
Theratronics sealed sources have been, and are presently used throughout hospitals worldwide.
No radiation incidents due to capsule failure have been reported to date.
L. IMITATIONS AND/OR OTHER CONSIDERATIONS OF USE:
The device shall be used only by Harper Hospital.
The device shall be leak tested at intervals not to exceed six (6) months using techniques capable of detecting 0.005 microcurie of removable contamination.
Handling, storage, use, transfer, and disposal:
to be determined by the licensing authority, Source transfer involves exchanging source drawers with a shipping container containing two drawer compartments.
REVIEWER NOTE: Prior to first use the device shall be tested for proper operation of the source exposare mechanism and safety warning components, leak tested and external radiation levels determined (source exposed, source shielded).
REGISTRY OF RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE NOV 0 61991 NO.: NR-687-D-107-5 DATE:
PAGE 7 OF 8 DEVICE TYPE:
Total Body Irradiator LIMITATIONS AND/OR OTHER CONSIDERATIONS OF USE: (Cont'd)
REVIEWER NOTE: This is a modified Theratron 780 teletherapy unit and is labeled as Model Theratron 780 serial # 19.
The following limitations are specific to this unit:
Only the modifications specifically noted in this certificate have been reviewed and approved.
Conversion to a standard teletherapy unit requires an amendment to this certificate.
The non-adjustable collimator is not to be removed except for service.
This device is not to be operated except in the downward position (i 5*) with the flattening filter fully installed.
Rotation of the device is only permitted when performing service on the device.
The device shall be installed on the lowest level of the facility (see description section) or in an area where appropriate floor, ceiling and wall shielding has been provided.
The dual timer, introduced with the Theratron 780-C is authorized to be used as a replacement timer for the device.
The device must be modified so that the operation of the dual timer remains as specified in product specification G85-281, Section 2.1, submitted February 13, 1985.
This registration sheet and the information contained within the references shall not be changed without the written consent of the NRC.
SAFETY ANALYSIS
SUMMARY
Based on our review of modified Model Theratron 780-19 and test data cited in the past review of the Theratron 780 Series teletherapy unit, we conclude that the Theratronics Model Theratron 780-19 Total Body Irradiator is acceptable for licensing purposes.
Furthermore, we conclude that this device would be expected to maintain its containment inta - 'ty for normal conditions of use and accidental conditions whs,. might occur during uses specified in this certificate.
)
O O
REGISTRY OF RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE i
UU NO.: NR-687-D-107-S DATE:
PAGE 8 OF 8 DEVICE TYPE:
Total Body Irradiator j
REFERENCES:
The following supporting documents for the Model Theratron 780-19 Total Body Irradiator are hereby incorporated by reference and i
are made part of this registry document.
Harper Hospital's letters dated May 17, 1991, September 18, 1991, October 15, 1991 and October 29, 1991 with enclosures I
thereto.
ISSUING AGENCY:
U.S.
Nuclear Regulatory Commission
/
Date; Reviewer:
Date:
Concurrence:
b' M 1
l l
F
')
REGISTRY OF RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE No.: NR-687-D-107-S DATE: NOV 0 6 199]
ATTACHMENT 1 NEAR SWlVil sCAll teAIN FRA418 NEA8
~..
}~
NEAS fANel i
..\\ A. iL% g,...
.]
C0ttlM ATOR SCAtt "
'r 1
CettIM ATOR PANk't CettMIATOR
(,
- k @
l j
.' s SANTRY sCAtt EANTRY---"*"
)
- .~-
%,)
.- F
, 'j
{4 a
J EASE
^isfreArts anota riconi Constra witswT as Asesverran seses:
Model Theratron 780 Teletherapy Unit l
l REGISTRY OF RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE NOV 0 (i 1991 NO.: NR-687-D-107-S DATE:
ATTACaMENT 2 f
enees
=
e 4.48e
-. -.33e
.sei -
j
.165
.448 *
=
/\\
Bj s
/
l
\\
i t
s 562 l e t
./
e
\\
/ !\\
/
I N
i I
/
I
\\
\\
ij
_ /i i
is i
i t
i t
i le e I
j 1
s al
'n 11 s IT a ij
- 12.7se L.
~ 5.4e8 -.
OI4.4%
.- 6.758 T YP.-+
+- 4.773 -.
TYP.
b y/-
\\p\\
e i
/
'g )
/
g 4.773 TYP.
t 1 y l
/
\\
l i
\\
t.
o 86 X) 8.344 THRu g
f
\\
/
\\
/
k 4
s s
~
FIXFD COLLIMATOR I
CEnEBIN l
l Model Theratron 780-19 Total Body Irradiator Non-adjustable Collimator
l REGISTRY OF RADIOACTIVE SEALED SOURCES AND DEVICES SAFETY EVALUATION OF DEVICE NO.: NR-687-D-107-S DATE:
il0V 0 61991 ATTACHMENT 3
+,. - E-p :ensc
'" * }3-.
{,p A,/
- ,aw ns..sa miavr couac y-w--
d>
"cw au rax wo> s 8
pf ps 1 eg g* p O f oCioA4
- 9 s
N
.I' 57,2%%
\\
s.
I
,no
-Q
/y..
l' b-ia,,,
s Oll"k m %--
ll t----s+-
I ll r-fromu sawsnais r
y,igga er y
\\
Em.
B~
rierrzau risren m., s..
L,
/
l srenoa e p
\\
rrenn a na l
a n
\\
l Model Theratron 780-19 Total Body Irradiator Flattening Filter Mount i