Follow Up on X-Ray Dosimetry in Children

["Richard, Mack L" <mrichar@iupui.edu>]

Radsafers:

This is just a follow up on my previous post about use of x-rays in research
studies involving children (or adults for that matter).  Just to each
everyone's mind, such study protocols go through detailed review by the
appropriate radiation safety committee (we have 3 - Machine Produced
Radiation Safety Committee - MPRSC, Radionuclide Radiation Safety Committee
- RRSC, or the Radioactive Drug Research Committee - RDRC) and the
Protection of Human Subjects Committee, commonly referred to as the IRB
(Institutional Review Board).

There's some interesting history about how these reviews evolved (if your
not interested, hit the "delete" key).  In the past, research studies
involving the administration of radioactive material or the radiation from
said material to humans for research purposes were reviewed by the RRSC or
RDRC in addition to the IRB.  The clinical use areas were aware of the
review requirements and automatically forwarded the protocols to our
committees for review.  If non-clinical use areas (i.e., by that I mean
other than nuclear medicine or radiation oncology) attempted to order
radioactive materials (the RSO orders all such materials here), we would ask
questions about its intended use at that time and initiate the review
process.

Human research studies involving machine produced radiation were another
matter.  Many human research studies may involve some type of x-ray (perhaps
a screening x-ray to eliminate certain diseases or conditions) as a
qualification for the study.  Since the investigator was not necessarily a
radiologist, he/she was not always aware that some type of radiation safety
review was required.  In an effort to assure such issues were addressed, the
IRB includes a couple of questions about the use of radiation and/or
radioactive materials in their application packet.  Soon after this was
done, I began getting calls from researchers with the comment, "I never had
to do this before!!"  This basically told me that x-ray use in conjunction
with human research studies was relatively common.  We reviewed about 15 of
these studies last year.

The key question we ask relates to how the radiation/radioactive materials
are being used.  Obviously, if a study involves comparison of "normal"
subjects and subjects with a specific disease, and the study includes some
type of radiation exposure, review by one of our committees is required
because the only reason the normal subjects receive exposure is due to their
voluntary participation in the study.  Another example where radiation
safety committee review is required is when a certain patient population
will receive radiation exposures (or additional radiation exposures) that
are not part of that patient's routine medical care (e.g., a patient with
cirrhosis of the liver participates in a liver drug study whereby he/she
will receive 2 more liver scans than a patient with the same disease who
elects not to participate in the study).  Such additional nuclear medicine
scans may represent additional risk.  They may represent additional benefit
if your a proponent of hormesis (but that's another issue - don't jump on me
about that).  Regardless of whether or not it represents a real risk, we
feel that we must inform the patient that they will receive additional
radiation exposures by participating in this study.  The actual statements
we use are based upon the radiation dose the subject receives (hence the
reason for my original post).

On the other hand, if a research study involves the use of x-rays, nuclear
medicine scans, etc. that are a part of a patient's routine medical care,
radiation safety committee review is not necessary (i.e., the patient will
receive the same radiation dose, regardless of whether or not they
participate in the study).

The main emphases of our radiation safety committees' review include an
evaluation of the ability of the proposed use of radiation to achieve the
information the researcher is looking for, the radiation dose to the
subjects, and the radiation risk wording in the Informed Consent Statement.
Based upon our committee's review, the researcher is informed of their
approval of the study along with any conditions of that approval.  The IRB
receives a copy of the approval letter as well.

This entire process may seem cumbersome and it is.  However, remember the
trouble the government got into for not informing research subjects about
the use of radiation?  We don't want to go there.  Questions and comments
are welcome.

Regards,

Mack L. Richard, M.S., C.H.P.
Radiation Safety Officer - IUPUI/Indiana Univ. Med. Cntr.
Phone #: (317) 274-0330   Fax #: (317) 274-2332
E-Mail Address:  mrichar@iupui.edu

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