Physics and Radiobiology of Nuclear Medicine

(Jeff_L) #1

directives are similar to NRC 10CFR20 and 10CFR35 regulations in the
United States and address all aspects of radiation protection to individuals
involved with radiation. They include exposure limits to workers, patients,
minors, pregnant women, nursing mothers, and members of the public,
monitoring of radiation areas and working personnel, designation of con-
trolled and supervised (restricted) areas, optimization of radiation exposure
(similar to ALARA in the United States), survey of work areas, training
and experience of the radiation workers and physicians, monitoring in the
case of accidental or emergency exposure, recordkeeping, reporting of inci-
dents, and so on. Note that the dose limits in these directives are the same
as those adopted by the NRC in the United States. The disposal, recycling,
or reuse of radioactive substances is required to have prior authorization,
but may be exempt from these requirements if the clearance levels of
radioactivity established by the member state comply with those of the
EURATOM directive. Directive 90/642 EURATOM provides regulations
for monitoring exposure to outside workers. Interstate shipment of radioac-
tive materials between member states is governed by Directive 1493/93
EURATOM. Similar to an RSO in the United States, a radiation protec-
tion advisor (RPA) is an expert in radiation protection principles, who
implements and supervises radiation safety regulations in institutions.
Although all EU regulations and directives are equally applicable to all
member states, the actual situation differs from country to country, because
of the lack of effective implementation of the rules in many states. So in
some member states, these directives are effectively implemented, and in
others they are leniently applied, and in some cases, there may be a breach
of these community laws.
It should be noted that detailed information of different directives given
above may be available from the EU Web site.


Questions



  1. Define committed dose equivalent, deep-dose equivalent, total effec-
    tive dose equivalent, radiation area, and high radiation area.

  2. What are the annual dose limits for radiation workers for:
    (a) Whole body
    (b) Lens
    (c) Extremities

  3. What is the dose limit in the unrestricted area and for the individual
    members of the public?

  4. (a) Calculate the exposure rate at 10 inches from a 150-mCi (5.55-
    GBq)–^131 I source (G 20 of^131 I =2.17 R · cm^2 /mCi · hr at 1 cm).
    (b) If the half-value layer (HVL) of lead for^131 I is 3 mm, how much
    lead is needed to reduce the exposure to 10% of the calculated
    value at 10 inches?


Questions 297
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