NASA Attachment 2


Draft NASA statement on a possible taxonomy of human radiation
experiments.


DRAFT

NASA Human Radiation Experiments
Taxonomy (Categorization) Considerations

General issues:
     Minimal risk exposures vs high risk exposures:  NASA deals
with minimal risk exposures (studies conducted by AEC at Oak Ridge
were exception)
     Special populations vs general populations:  NASA deals with
astronaut employees who are a special population in terms of their
potential subjugation as research subjects -- Numerous ethical
issues are involved in the use of astronauts as experimental
subjects in biomedical research, particularly around the issue of
consent and balancing of (1) need for understanding of biomedical
effects of space flight, (2) large investment in astronaut
training, and (3) astronauts' autonomy regarding participation as
subjects in biomedical research.

Definition of "human radiation experiments"  (Executive Order No.
12891):
     (1) Experiments on individuals involving intentional exposure
to ionizing radiation.  This category does not include common and
routine clinical practices, such as established diagnosis and
treatment methods, involving incidental exposure to ionizing
radiation.
     (2) (irrelevant to NASA -- no intentional environmental
releases designed to test human exposure)

Concerns with definition (intent) and needs for clarification:
     1. Does definition (1) mean any intentional exposure to
ionizing radiation in an experimental context or does it mean
intentional exposure to ionizing radiation for the purpose of
studying radiation effects?
     2.  Does definition (1) include retrospective studies of
radiation effects?  A retrospective study could not involve
"intentional exposure to ionizing radiation" from the point of 
view of the retrospective study, even if the initial exposure was
intentional.

Included in definition (intent):
     Early human dose-response studies conducted by AEC at Oak
Ridge.
     Development of techniques to measure total-body calcium using
whole-body neutron exposures.
     Development of techniques for determining bone and soft tissue
composition using radionuclide absorptometry.
     Light-flash experiments

Probably not included in definition (intent), but NASA including in
review:
     Any use of X-rays, radioisotopes or other clinical exposures
given in an experimental context, not given for the direct benefit
of the patient (subject) -- studies on astronauts (special
population), bed-rest studies to determine effects of reduced
gravity on human physiology (not special population -- minimal
exposure, low radiation risk), etc.
     Any retrospective study of radiation effects involving
intentional exposure to ionizing radiation, even if that exposure
resulted from "established...treatment methods" for the patient's
benefit -- Radiation Health NASA Specialized Center of Research and
Technology (NSCORT) study of cataract development in patients
exposed to high energy helium ions for treatment of uveal
melanomas.
Not included in definition (intent):
     Occupational exposures in routine ground-based activities
(loading radioactive sources aboard spacecraft, work with and
routine clinical monitoring using X-rays and radioisotopes, etc.) -
- monitored as part of routine occupational health program which is
not research.
     Occupational exposures of astronauts (space flight, routine
clinical monitoring using X-rays and radioisotopes) -- monitored as
part of Longitudinal Study of Astronaut Health, but not
"intentional exposure to ionizing radiation" for the purpose of
studying radiation effects.