5 rem (50 mSv) total effective dose equivalent, or has resulted in unintended
permanent functional damage to an organ or biological system of the
child.
The conditions, timing, and descriptions of the report are identical to
those of the medical events described above.
Release of Patients Administered with
Radiopharmaceuticals
According to 10CFR35.75, a licensee can release a patient administered
with a radiopharmaceutical or a permanent radioactive implant, provided
the TEDE to any other individual from exposure to the released patient is
not likely to exceed 500 mrem (5 mSv). Practically in nuclear medicine,
patients treated with^131 I-NaI are commonly considered under these
regulations. In these cases, when the activity in the patient is less than
33 mCi (1.2 GBq) or the measured exposure rate is less than 7 mrem/hr
(0.07 mSv/hr) at 1 meter, then the patient can be released. However,
patients administered with higher^131 I-activities, as high as 200 mCi
(7.4 GBq), may be released provided the dose calculations using patient-
specific parameters show that the potential TEDE to any other individual
would be no greater than 0.5 rem (5 mSv; NRC Regulatory Guide 8.39). The
patient-specific calculations depend on the choice of the occupancy factor
and the physical or effective half-life. An occupancy factor of 0.75 is chosen
for t1/2of less than one day and a value of 0.25 for t1/2greater than one day.
A value of 0.25 for the occupancy factor would be valid if the patient follows
the instructions, such as, for the first two days, (1) maintain the distances
from others; (2) sleep alone or, better yet, live alone; (3) do not travel by
airplane or mass transportation; (4) do not travel in automobiles with
others; (5) have the sole use of the bathroom; (6) drink plenty of water; and
(7) limit visits by others. These instructions must be given in writing to the
patients to follow after release.
The released patient must be given instructions, including written instruc-
tions, to maintain the dose as low as reasonably achievable if the TEDE to
any other individual is likely to exceed 100 mrem (1 mSv). In the case of^131 I
treatment, instructions must be given to the patient, when the activity in the
patient is more than 7 mCi (259 MBq) or when the measured exposure rate
exceeds 2 mrem/hr (0.02 mSv/hr) at 1 meter. If the dose to a breast-fed
infant or child could exceed 100 mrem (1 mSv) assuming continuous breast-
feeding by a patient administered with a radiopharmaceutical, then instruc-
tions on discontinuation of breast-feeding and consequences of failure to
follow the guidance must also be given. Table 16.3 lists the activity limits
for giving instructions to the breast-feeding patients and activity limits for
cessation of breast-feeding.
290 16. Radiation Regulations and Protection