Re: population exposure

[antatnsu@pacbell.net]

David, I would hazard a guess that two of the reasons are:

1.  Occupational exposure is regulated.  Patient exposure is not.
Therefore, much work is done to comply with the regulations.  Not much is
done to lower patient dose because, what are the standards for patient
doses?  There aren't any.  So, what would the practitioner work toward?
Many of us now believe that low doses aren't particularly harmful, if at
all, and may be beneficial.  If a patient had multiple exposures over time,
which ones should be lowered (if any)?

In a way I share your concern about high patient doses.  I just had an
angiogram yesterday.  I don't have the official dose yet, but I'm told it
will be in the tens of rem to the irradiated area.  What the Effective Dose
will be is left to the student to calculate.  However, the result of the
procedure was to give my cardiologist the precise information he needed to
tell me that I must have bypass surgery within the next ten days.  So, I
think the information is worth the dose, especially since I am 70 years old
which makes cancer induction, if any, not much of a problem.

2.  Medical exposure is of immediate benefit to the patient (see above).  If
we really knew the risk as a function of dose, it might be a factor in the
risk-benefit evaluation.  But, diagnostic nuclear mecidine doses are usually
very low.  Dental x-rays, at least in California, require a lead apron over
the patient to reduce the dose.  Other diagnostic x-ray exposures such as
chest x-rays are low dose exposures (10s of millirem).

So, for me, medical exposure may be high, but it is worth it for the
information or treatment received.  Also, I know of no scientific studies
that demonstrate any harm from medical exposure.  If there are any, perhaps
another radsafer could cite them for you.

However, it does seem incongruous that we spend so much to reduce
occupational and public doses from nuclear industry activities when we don't
for patients.  Actually, patient doses have been significantly reduced from
doses received in earlier decades.  It's just that the new techniques result
in more nuclear procedures so the collective dose (if that is meaningful) is
higher.  Perhaps we should look at it another way and ask why don't we
permit higher occupational and public exposures to match the medical
exposures since the benefits are so great from the nuclear industry.

As an aside, it was interesting that the nurse in the cardiac lab knew
absolutely nothing about natural background or that her body contained
natural radioactive material.  Chalk up one more slightly educated nurse
after about 20 minutes of information transfer.

Al Tschaeche, CHP antatnsu@pacbell.net

David Adcock wrote:

> Could someone explain to me why so much physicist effort, at
> least in the United States, is devoted to controlling occupational
> exposure to ionizing radiation while so little is directed toward
> reducing medical (including dental) exposure?
begin:          vcard
fn:             Al Tschaeche
n:              Tschaeche;Al
org:            Nuclear Standards Unlimited
email;internet: antatnsu@postoffice.pacbell.net
title:          CEO
x-mozilla-cpt:  ;0
x-mozilla-html: FALSE
version:        2.1
end:            vcard