U.S. Nuclear Regulatory Commission

Technical Assistance Request, Use of Portable Shields for a High Dose Rate Afterloader Facility at Washington Hospital Center, Washington, D.C.

HPPOS-317 PDR-9306280268

Title: Technical Assistance Request, Use of Portable

Shields for a High Dose Rate Afterloader Facility at

Washington Hospital Center, Washington, D.C.

See the memorandum from J. E. Glenn to R. R. Bellamy dated

June 25, 1992. This NMSS memo responds to a technical

assistance request from Region I, dated March 26, 1992,

concerning Washington Hospital Center's request to relocate

their high dose rate afterloader to a new location and use

portable lead shadow shields to obtain compliance with the

dose limits of 10 CFR 20.1301 for members of the public.

The request was reviewed and the following guidance is

given.

Although NRC's Policy and Guidance Directive, FC 86-4, for

licensing high dose rate afterloaders presumes the

necessary room shielding is obtained by the use of

appropriate fixed wall, floor, and ceiling materials, it

does not explicitly require it. However, portable shield

should not be permitted as a permanent means of providing

shielding for high dose rate afterloading facilities. This

requirement is consistent with the recommendations

contained in the most recent draft of the AAPM Task Group

on Remote Afterloading Systems.

Washington Hospital Center may be allowed to use the

portable shields on a temporary or emergency basis to

insure patient care is not impacted. If portable shield

are used, a positive method of ensuring the shield (s) are

correctly positioned for each treatment must be provided,

and "per patient" surveys must be performed for each

treatment to insure that exposure rates in unrestricted

areas comply with 10 CFR 20. The licensee would be

expected to commit to the installation of appropriate

permanent shielding within a reasonable period of time.

The hospital must be made aware that the use of a

cantilevered shield for limiting the exposure to the

adjacent uncontrolled area above the treatment room may

raise additional safety concerns about patient injury from

improper design, maintenance, or mishandling during

positioning of the shield.

After review of the technical assistance request, the

licensee apparently omitted any description of the area

security for the treatment room. Such a description is

required by V (c) of FC 86-4. Since the licensee is

proposing to locate the high dose rate afterloader with an

existing superficial treatment machine, it is essential

that they implement and describe a means of assuring that

only one of the two radiation producing devices can be

operated at a time. Also, the proposed shadow shield for

the door and window would appear to obscure observation of

the patient during treatment. If this is the case, the

licensee must provide an alternate means of viewing the

patient during treatment.

Regulatory references: 10 CFR 20.1301, 10 CFR 20.1302

Subject codes: 4.4, 5.3, 7.1, 12.8

Applicability: Byproduct Material