ML23156A430
| ML23156A430 | |
| Person / Time | |
|---|---|
| Issue date: | 03/09/1987 |
| From: | NRC/SECY |
| To: | |
| References | |
| PRM-035-006 | |
| Download: ML23156A430 (1) | |
Text
DOCUMENT DATE:
TITLE:
CASE
REFERENCE:
KEYWORD:
ADAMS Template: SECY-067 03/09/1987 PRM-035-006 - - PETITION FOR RULEMAKING - DELETE THE NEGATIVE PRESSURE RADIOACTIVE AEROSOL ADMINISTRATION ROOM REQUIREMENT PRM-035-006 RULEMAKING COMMENTS Document Sensitivity: Non-sensitive - SUNSI Review Complete
DOC'<ET I UMBER E:.ITION RULE PRM.J§"--&;;
Mallinckrodt, Inc.
2703 WAGNER PLACE MARYLAND HEIGHTS, MO. 63043 March 9, 1987 Mr. Samuel J. Chilk Secretary of the Commission U.S. Nuclear Regulatory Commission 1717 "H" St. NW, Room 1121 Washington, D.C.
20555 ATTN : Chief, Docketing and Service Branch
Dear Mr. Chilk:
(314) 344-3800
~7 HAR t1 AlO :03 Mallinckrodt, Inc. hereby petitions the U.S. Nuclear Regulatory Commission (NRC) for rulemaking to modify 10CFR35.205, which becomes effective April 1, 1987.
If accepted by the NRC, the petition would delete the negative pressure radioactive aerosol administration room requirement set forth in 10CFR35.205(b).
Deletion of the negative room pressure requirement, would preclude the adverse impact it would have on the delivery of health care to patients with pulmonary diseases. The technical basis for this petition and recommended regulatory text, are provided in the enclosed Bas{~ *for Petition for Rulemaking to Change 10CFR35. 205.
We have coordinated the development of this petition with Mr. Norman L. McElroy of the Materials Licensing Branch.
Should you desire further information or have any questions, please do not hesitate to call me at (800)325-3688.
Sincerely, L. G. Struttman Division Medical Physicist Professional Services Department LGS/jjk Enclosure cc:
Mr. John L. Crenshaw fMiiit
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Problem BASIS FOR PETITION FOR RULEMAKING TO CHANGE 10CFR35.205 In the revision of 10CFR35, identical safety measures are applied to radioactive gases and aerosols.
However, the safety measures needed to assure public health and safety are different for the two.
Recommendation Safety measures that are not needed to assure the safe use of radioactive aerosols should be removed from the regulations.
Background Information GASES AND AEROSOLS -
THE DIFFERENCE Physical The molecular diameter of xenon gas is 0.00034 to 0.0004 micron.
Tc99m DTPA aerosol particle diameter is 0.1 to 1.0 micron -
approximately three orders of magnitude larger.
This is the size of the aerosol particles produced by nebulizers (aerosol production devices) currently used in nuclear medicine.
one micron= one-millionth of a meter Administration Devices Xenon-133 gas is usually administered to the patient with a delivery system that incorporates a spirometer or similar device for rebreathing the gas.
The system is preloaded with xenon gas.
When the study is terminated, the patient breathes the xenon gas residual, remaining in the lungs, into a trap.
The total time the patient is breathing "on" the delivery ~rstem is
- approximately 10 to 20 minutes.
Up to 30 to ~-0 millicuries of Xenon-133 gas remains in the delivery system upon termination of the study.
This system is reusable.
1 -
Tc99m DTPA aerosol is administered with an administration device, such as the UltraVent, which delivers the aerosol to the breathing tube mouthpiece for inhalation.
The aerosol is produced by a venturi type nebulizer.
Twenty-five to 35 millicuries are placed into a reservoir in the device.
The patient inhales aerosol from the device for 3 to 5 minutes.
During this inhalation period approximately 1 to 2.5 millicuries are deposited in the patient's lungs.
Any aerosol not deposited in the lungs is exhaled back into the device and filtered out of the exhaled air by the trap-filter.
(see Appendix C)
This is a single use only device.
Administration/Clinical Utility Xenon-133 gas is administered to the patient throughout the lung ventilation study, which precludes its administration to a patient on a breathing assistance device (respirator), due to mechanical incompatibility of this device and the gas delivery system.
Tc99m DTPA aerosol is administered before the study and can be administered to a respirator patient, since the device is mechanically compatible with the respirator.
Therefore, the patient can remain on the respirator during the administration procedure.
Biodistribution The xenon gases are inhaled, diffuse through the alveolar lining, enter the cardiopulmonary circulation through the venous capillaries, and diffuse back into the alveoli and are exhaled.
Tc99m DTPA aerosol is inhaled, 70 to 90% (Ref.1) is deposited on the alveolar lining, diffuses through the lining and enters the blood through the venous capillaries.
The biological half-life of this process is approximately one hour.
From this point it is distributed throughout the body in the same manner as intravenously administered Tc99m DTPA.
The 10 to 30% that is not absorbed into the blood is exhaled back into the aerosol administration device, where it is trapped in the filter in the exhaust port.
2 -
PHYSIODYNAMICS OF RADIOAEROSOLS Inhaled radioaerosols, with particle diameters of one micron or less, distribute evenly throughout the entire normal respiratory tract, including the terminal bronchioles and alevoli.
Soluble DTPA radioaerosol particles of this size are absorbed, by diffusion, through the alveolar lining, enter the capillaries, and remain in the blood to undergo biodistribution as DTPA.
The half-life for particle absorption into the blood, in the normal lung, is approximately one hour.
Radioaerosol particles larger than 1 to 2 microns do not permeate the entire lung field, but deposit only on the bronchial tree lining.
The larger particles are deposited proximal, and the smaller particles distal, to the primary bronchi, respectively.
This particle distribution pattern is referred to as central deposition.
Proposed Revisions The following regulatory text was published October 16, 1986 (51FR36932) to be effective April 1, 1987.
Control of aerosols and gases.
Paragraph itl states -
~ licensee that administers radioactive aerosols or gases shall do so in a room with a system that will keep airborne concentrations within the limits prescribed Q.Y. sections 20.103 and 20.106 of this chapter.
The system must either be directly vented to the atmosphere through an air exhaust or provide for collection and decay or disposal of the aerosol or gas in~
shielded container.
Revision None.
Justification Compliance with Sections 20.103 and 20.106 maximum permissible concentration (MPC) measured in microcuries/milliliter of air for restricted and unrestricted areas, respectively, of this paragraph are needed to assure public health and safety.
3 -
NOTE:
The UltraVent is a fully integrated radioaerosol delivery system which includes a highly efficient (99.99%) aerosol trap (Ref.2).
The manifold assembly is sonically welded.
Each unit is tested for leakage in accordance with the testing specification set forth in Appendix A(3).
The UltraVent is housed, during use, in Catalog No. 685 UltraVent Shield.
This shield provides a secondary barrier against any radioaerosol leakage, from the unit, entering the ad.ministration room (see Appendix A and B).
The potential leakage (loss) points external to the shield, and therefore in communication with the room, are at Points @, (B) and @
- described below.
( see Appendix C for illustration)
Point
- Is the juncture between the manifold and the plastic patient-breathing tube.
It is user-assembled.
Estimated leakage incidence frequency:negligible during routine and proper use.
Point
- Is the juncture between the mouthpiece and the patient's mouth.
Leakage (loss) will occur here only if there is patient noncompliance.
For example:
(1) the patient is exhaling past the outside of the mouthpiece (lips not conforming to the mouthpiece), or (2) the patient rejects the mouthpiece entirely.
Estimated leakage incidence frequency:
10% of patients.
Duration of incident:
2 to 3 exhalations, if ad.ministration procedure is constantly monitored.
Total rejection of mouthpiece is rare, and offers a negligible contribution to Tc99m DTPA aerosol losses, if the administration procedure is constantly monitored.
Point
- Is at the patient's nose.
If the provided nose clamp is not fitted to the nose properly by the user, or the patient, partially or totally, removes the clamp; some of the radioaerosol can be exhaled into the room.
Approximately 70% to 90% of the inhaled Tc99m DTPA aerosol is retained by the lungs.
The total estimated average quantity of Tc-99m per single exhalation, is presented below under Paragraph l.hl_.
Estimated leakage incidence frequency:
5% of patients.
Duration of incident:
1 to 2 exhalations, if administration procedure is constantly monitored.
The probability of leakage occurring simultaneously at Points @ and is slight.
In the event they did, the quantity lost would be equivalent to the greater of the two sources of leakage.
Point is used in the patient workload calculations below.
4 -
Paragraph lhl_ states -
A licensee shall administer radioactive aerosols and gases in rooms that are at negative pressure compared to surrounding rooms.
Revision Delete.... "aerosols and".... from this paragraph.
Justification Up to an average of 238 patients per week may be administered Tc99m DTPA aerosol, in an unrestricted area using clinically reasonable assumptions, without exceeding NRC requirements for maximum permissible concentrations (MPC) for Tc-99m.
DETERMINATION OF PATIENT WORKLOAD THAT WOULD BE NEEDED TO REACH MPC The following calculation shows that a hospital would have to carry an unreasonably large patient load before the air concentration of Tc-99m would approach the applicable MPC.
For the purpose of this calculation, the physical decay of Tc-99m is ignored.
TYPical Administration Protocol (Refer to attached Instructions for Use -
Appendix A)
- 1.
Oxygen flow rate= 10 L/min.
- 2.
Tc99m DTPA solute in radioaerosol generator (nebulizer) = 30 mCi in 2 mL of DTPA solution)
- 3.
Radioaerosol inhalation time= 3 min.
5 -
RADIOAEROSOL ADMINISTRATION LOSS Assumptions Inhalation period= 3 min.
Total Tc99m DTPA aerosol delivered to mouthpiece and inhaled by patient= 1500 uCi/3 min= 500 uCi/min.
(Ref.3)
Inhalations/exhalation cycles per minute= 22.
Retention of Tc99m DTPA aerosol by lungs= 80%/inhalation.
Expulsion of Tc99m DTPA aerosol per exhalation= 100%-80% = 20%
of inhaled quantity.
Tc99m DTPA aerosol in one exhalation=
500uCi/Min ~ 20%exhaled:inhaled ratio 22exhalations/min.
= 4.5 uCi/exhalation Fraction of noncompliant patients (where Tc-99m escapes past patient mouthpiece and/or noseclip due to noncompliance) = 10 out of 100 = 10%.
Calculation Administration Loss per Patient= 4.5 uCi/exhalation x 3 non-compliant exhalations/patient x 10% noncompliant patients=
1.35 uCi/patient.
6 -
RADIOAEROSOL CONCENTRATION IN ROOM AIR Assumptions Room Size -
12x15x9 ft= 4.587xl0E07mL.
Room Ventilation -
No exhaust ventilation.
Room at neutral pressure relative to surrounding rooms, Maximum Permissible Tc-99m Concentration (MPC) -
Unrestricted Area (UA) = lxl0E-06uCi/mL.
Calculation Unrestricted Area (UA)
NP(W) = RC(UA) x RV x D/WK AL Where:
= lxl0E-06uCi/mL x 4.587xl0E07mL x 7 1.35uCi/patient
= 238 patient administrations/week AL
= Administration loss (uCi/patient)
D/WK
= Days/week NP(W) = No. of patient administrations/week.
RC(UA)= MPC-Room Tc-99m concentration-unrestricted area-(uCi/mL)
RV
= Room volume (mL)
In summary, the above calculation demonstrates that an inordinately large number of lung ventilation imaging studies can be performed, and still not exceed the NRC maximum permissible concentration (MPC) limits for Tc-99m in an unrestricted area.
Thirty (30) studies per week is a patient workload seen in only the largest of hospitals.
7 -
ROOM SURFACE RADIOCONTAMINATION DETERMINATION Surface Technetium-99m Activity Tc99m DTPA aerosol particles produced by the UltraVent device, with a particle size range of 0.1 to 1.0 micron, have very low terminal valocities, and therefore have low settling rates.
Particles with low settling rates will tend to disperse.
The range of dispersal will, of course, depend on air currents prevailing at their source of origin.
Those particles that do disperse will be carried off with the circulating air.
Those that settle to the floor will contribute to surface contamination.
They will be referred to as non-dispersed aerosol particles.
For the calculation below it will be assumed that 50%
of the particles will disperse and 50% will not.
A maximum patient workload is calculated below, for unrestricted areas.
It will be assumed that negligible Tc-99m room surface contamination will remain, to be carried over to the next day, due to decay.
Assumptions -
Non-dispersed aerosol particle factor (NDF):50%
Tc99m DTPA aerosol administration protocol:Same as described under Patient Workload Determination above.
Tc99m DTPA aerosol administration loss (AL) :1.35 uCi/patient.
Surface area-floor (SA) in 12x15x9ft. room:1.672x10E05sq.cm.
Unrestricted Area-SC(UA) maximum allowable Tc-99m surface contamination:lxl0E-05uCi/sq.cm Calculation Unrestricted Area -
SC(UA)
Patient administrations/day= SC(UA)
= lxl0E-05uCi/cmE02 ~ 1.672xl0E05cmE02 1.35uCi/patient x 0.5
= 2.5 patients/day
= 2.5 x 5day/wk = 12.5 patients/week 8 -
In summary, twelve (12) studies per week is considered a large workload, even in large hospitals, The actual number of studies that can be performed in the hospital can be much greater, since many of the studies are performed in different rooms.
Paragraph 19..l states -
Before receiving, using, or storing~ radioactive gas, the licensee shall calculate the amount of time needed after~ spill to reduce the concentration in the room to the occupational limit listed in Appendix~ to Part 20 of thi-s chapter, The calculation must be based on the highest activity of gas handled in~ single container, the air volume of the room, and the measured available air exhaust rate.
Revision
- None, Justification Does not refer to aerosols.
Paragraph _{_fil states -
& licensee shall make~ record of the calculations required in Paragraph _{_Q_l_ of this section that includes the assumptions, measurements, and calculations made and shall retain the record for the duration of use of the area.
& licensee shall also post the calculated time and safety measures to be instituted in case of a spill at the area of use.
Revision None.
Justification Does not refer to aerosols.
9 -
Paragraph J.tl states -
A licensee shall check the operation of collection systems each month, and measure the ventilation rates available in areas of use each six months.
Revision Add -
For areas where radioactive gases are used,~ licensee shall...
Justification To clarify that these measures apply only to areas where radioactive gases are used.
Summary In many large, medium and small size hospitals, Tc99m DTPA Aerosol is the lung ventilation imaging procedure of choice.
In large hospitals, it is used in Intensive Care Units (ICU) and Critical Care Units (CCU), or, in the case of critically ill patients, in their hospital room.
Xenon-133 gas cannot, of course, be used in these rooms.
In the medium and small size hospitals, radioaerosols are used in the above locations, and in those hospitals with no negative-pressure xenon gas administration room, it is the only method for performing lung ventilation imaging procedures.
Furthermore, it is the most cost-effective method of acquiring this type of diagnostic information.
In view of the minimal risk, when properly used, attendant to the use of radioaerosols for lung ventilation studies, it would seem appropriate not to impose the negative room pressure requirement for radioaerosol administration upon the Nuclear Medicine Community.
Imposition of this requirement would have an adverse impact on the public health and safety because it would make it difficult, or impossible, for physicians to administer necessary clinical procedures to critically ill patients.
Your consideration of not making "negative room pressure" a recommendation to the Agreement States is also earnestly sought.
10 -
References
- 1.
Clark, SW and Pavia, D. Aerosols and the Lung:Clinical and Experimental Aspects.
Butterworth & Co., London, 1984, p.95.
- 2.
Russak, Salmon and O'Brien, Consulting Health Physicists, Bellevue, WA.,
Radiation Safety Evaluation of SynteVent Aerosol Delivery System - Final Report.
May 30, 1984.
- 3.
Struttman, LG, Product Background Report - UltraVent Radioaerosol Delivery System, 4th Edition.
Mallinckrodt, Inc., St. Louis, MO., February 19, 1986, p.16.
- 4.
Struttman, LG, Radioaerosols and the Regulatory Process.
18th Annual National Conference on Radiation Control, Conf. Publ.
-87.2, Conference of Radiation Control Program Directors, Inc.
Frankfort, KY., Jan., 1987, pp.41-48.
L. G. Struttman Division Medical Physicist
/jjk 03/06/87 11 -
684 RB/86 UltraVent' Radioaerosol Delivery System For Single Patient Use HilM" mfg. for:
Diagnostic Products Division Malllnckradl, Inc.
St. Louis, M083134 2 Secure plastie tubing/mouthpieee
- assembly to the end of the manifold oppoelle the aerosol frap.
3 Open lhe UltraYent Shield (CalalOg No.
' 685) by rolaling the handles down and lifting lhe cover. Remove lhe inner lid (wilh handle)
Caution: Federal (U.S.A.) Law restricts this device to sale by or on the order of a physician.
4 Attach lhe manifoldllrap assembly to the
- retaining mechanism on the bollom side of lhe inner lid. Rolale lhe black locking knob on the release lever on lhe upper side of lhe lid.
Confirm that lhe assembly is firmly attached.
5 Firmly attach lhe cut-end of !he Ai1102
- lnterconnector to lhe air/oxygen inlet nozzle at the base of the radioaerosol generator UltraVentrM Ventilation Kit and Shield Instructions for Use Warning: This ventilation kit is FOR SINGLE PATIENT USE ONLY. Reuse can cause cross-infection. After using this ventilation kit once. it should be disposed of usin~ appropriate techniques for the disposal of biohazardous materials.
Assembly Instructions 1 Remove the UltraVenl Venlilation Kit from its
- _packaging. Components include:
- a. Radioaerosol generator
- b. Manifold fitted with aerosol trap (bacterial filter)
- c. Plastic tubing
- d. Noseclip
- e. Airt02 lnterconnector
- f. Mouthpiece 6 Attach the other end of the Airt02
- lnterconnector lo lhe oxygen supply. Note:
7 Place the radioaerosol generator. with
- Air/O2 lnterconnector attached, into the well in the base of the shield. Align the generator's air/oxygen inlet nozzle with the corresponding slot in the plastic base.
and press the generator down until it seats snugly in the base Compressed air may also be used with the UltraVent.
Check oxygen source and tubing for obstructions. leaks and secure connections.
- Assure that the generator is level 8 Route lhe Alr/02 tnterconnector tubing out
- the patient end of the shield by means of the channel provided. Secure the tubing by pushing tt into the narrow channel at the patient end of the shield
- Confirm that the tubing will not crimp.
nor Impede the reinstallallon of the Inner lid and manifold l>
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g Check tor proper o,cygen flow by e1aw1y
- turning on the oxygen. to a flow rate ot 9 to 12 literstminute. Place hand over the top ot the radioaerosol generator to ensure a steady oxygen flow.
Nole: It a water bottle or humidifier is attached to the oxygen source. it must be detached tor system to operate properly.
- 10. Turn oft oxygen.
11 Prepare the Tc 99m OTPA according to 13 Immediately reinstall the inner lid such that
- the manifold assembly engages the radioaerosol generator and the tubing mouthpiece assembly exits from the patient end of the shield. Press the inner lid down firmly until the manilold/radioaerosot generator locking engagement is heard and felt.
- manufacturer's instructions. See RadfbaerOSOI Administration Protocol for concentration to be used.
- 12. Using a shielded syringe inject a minimum ol 2 ml Tc 99m OTPA solution into the radioaerosol generator through the top opening.
d Rad1oaerosol inhalation period -
3 to 5 minutes Post-perfusion:
a Use Tc 99m MAA dose of 1 to 2 mCi.
b Oxygen !low rate -
11 to 12 liters1minute c Volume of solution added to rad1oaerosot generator -
2 to 3 mt.
d T echnetium-99m con.centration ot solution added to radioaerosot generator -
25 to 30 mCiiml.
e Rad1oaerosot inhalation period -
4 to 1 o minutes Operating Instructions 1 Place the mouthpiece in the patient's
- mouth, making sure the tongue is under the mouthpiece and not occluding the opening.
- 2. Apply the noseclip.
Nole: Once the radioaerosol generator is locked to the manifold they cannot be separated.
14 Close the cover and rotate the handle
- opposite the patient to the locked position.
3 Instruct the patient to take live or six
- test breaths (normal tidal breathing) from the system before the oxygen is turned on. This assures that oxygen flow is unimpeded and the patient is familiar with the breathing techniques.
4 Gradually turn on oxygen (taking 2 to 4
- seconds (max.) to attain a !low rate of 9 litersiminuteJ. Then adIust flow rate to desired setting.
Caution: Abruptly turning the flow rate to final setting may detach tubing from radioaerosot generator 5 Instruct the patient to breathe normally
- through the system until the desired amount ot radioactivity is delivered to the lungs. No holding ot breath is necessary.
Caution: In order to reduce the risk of radiation leakage into the environment.
Aadloaerosol Administration Protocol Oxygen flow rate. rad1oact1vlly concentration.
and radioaerosol Inhatat1on period may be varied to accommodate the protocol desired Increasing oxygen flow rate. concentration ot rad1oac11vity. andtor rad,oaerosol inhalation time will increase deposition ot rad1oactivrty in the lung allowing: laster rmagIng. ettic1ent collection ot more counts per image. and use of the system for post-perfusion or SPECT studies SUGGESTED PROTOCOLS Preperlusion.
- a. Oxygen flow rate -
10 to 12 liters,minute b \tllume ot solution added to rad1oaerosot generator - 2 to 3 mt
- c. Technetium-99m concentration ot sotutIon added to rad1oaerosot generator -
15 to 20 mC1/ml ensure that the mouthpiece Is held securely in the patient's mouth before initialing airflow. Be p...,.,.i throughout the lnhlllatlon period to shut off oxygen flow lmmedllltaly " the patient rele*- the mouthpiece.
6 Alter inhalation. turn oft the oxygen and
- instruct the patient to continue breathing through the mouthpiece taking live Ilda!
breaths before coming oft the system
- 7. Remove the noseclip 8 Imaging may be performed immediately. or
- the patient may be moved to another location for imaging.
Nole: A large lietd-ot-view gamma camera with a low-energy, all-purpose collimator Is recommended.
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Dlaposal Instructions Caution: The ventilation kit should be disposed of using standard techniques for the disposal of boohazardous materials.
1 To remove the Ultra\lent device, lower
- handles, open cover.
2 Disconnect AirtO2 lnterconnector from
- oxygen supply filling.
3 Lift the inner lid straight up, removing the
- entire radioaeroSOI o-ratortmanifold assembly from the shield, making sure to pull the oxygen supply tubing out of its retaining channel.
4 To remove the radloaerosot
- g-rator/manifotd assembly from the inner lid, position the unit over a shielded disposal container, and rotate the locking knob to the open position. Push the release latch forward while tilting the lid upward.
Nola: The unit should drop olf easily into the shielded disposal container.
5 Alternatively, the contaminated unit may be
- stored in the shield until ii can be appropriately dispoH99.9%
(2) Aerosol Particle Size Size Distribution:
0.25 micron MMAO* (geometric s.d. 2.05)
Microns MMAO
>2.0 2.0 to 0.9 0.9 to 0.45 0.45 to 0.155
<0.155 Percent 0.4 2.2 20.7 33.6 43.1 (3)
Gas Flow Rate:
- Maximum - 13 liters/min.
- Minimum - 8 liters/min.
(4)
Volume of Solution Added to Radioaerosol Generator:
- Maximum - 8 milliliters
- Minimum - 2 milliliters
+-
0--
Figure 4. UltraVent* Ventilation Kit Legend:
(1) Mouthpiece (2) Plastic Tubing (3) Manifold (4) Check Valve (5) Check Valve
<::=>Aerosol Fl ow Inhalation APPENDIX C (6) Radioaerosol Trap (7) Radioaerosol Generator (8) Flow meter (liters/min)
(9) Gas Regulator (10) Oxygen or Compressed Air
+- Expired Air Flow
-a Room Air
- Aerosol flows from Radioaerosol Generator (7),
- Into Manifold (3),
- And through Plastic Tubing (2),
- Into Mouthpiece (1).
- Room air is aspirated through Radioaerosol Trap (6).
- Opens Check Valve (4),
- Andis mixed with aerosol.
- Check Valve (5) is in the closed position.
Exhalation
- Expired air flows into Manifold (3) via Plastic Tubing (2),
- Opens Check Valve (5) - (Position shown in Figure 4),
- And closes Check Valve (4) - (Position shown in Figure 4),
- Flows into and through Radioaerosol Trap (6),
- Into the room with the radioaerosol remaining in Radioaerosol Trap (6)
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