RE: LNT and resources [Was: Scientific responsibility]

["NIXON, Grant (Kanata)" <GNIXON@MDS.Nordion.com>]

Hi John,



Why the repeated issue raised with the dose rate specified? It is a very

simply matter to arrive at a 3 mR/h figure for a glove box. Consider the

dose rate for steady operational conditions, say 2000 hrs/yr. Use a 5 rem/yr

limit and, voila, 2.5 mR/h is the limiting field. Say your head is located 6

inches from the outside of the glove box. Hence, you need to reduce the

field to below ~3 mR/h at 6 inches from the surface of the glove box. ALARA

would require an attempt to reduce this figure even further, but let's keep

it simple.



We have 4 cyclotrons (3 in Vancouver and 1 in Fleurus), not to mention 2

dedicated medical isotope reactors (MAPLE I and II at Chalk River for, among

other things, supplying ~80% of the world's need for Mo-99 and we are

currently using AECL's NRU reactor). We also make use of CANDU reactors for

Co-60 production. We also produce several exotic isotopes (e.g., we are

probably the sole supplier of I-123). Is any of this relevant to the

question at hand?



Not all things get automated until the technology is proven and the market

is established or proven to be receptive. When predominantly weak gamma

emitters have low-intensity but pesky high-energy components, these cannot

easily be piggy-backed onto existing glove-box technologies applicable to

other, similar isotopes devoid of these high-energy components, and the

costs associated with experiment or production then run-up. This is because

of, rightly or wrongly, the LNT theory, ALARA, and the person-rem

"accounting practices" that has been entrenched in legislation. So, yes,

there are prices to pay for unproven theories that have been entrenched into

legislation. It is not beyond the realm of possibility that this legislated

dogma may possibly be doing the public a huge disservice. That was the only

point I wished to make.



If you wish to follow-up with more discussion, perhaps we should do it

offline, I worry that we may bore more people into abandoning the list.



Best regards,



Grant Nixon, B.Sc., M.Sc., Ph.D. (a.k.a. irrelevant "alphabet soup")

Radiation Physicist



-----Original Message-----

From: John Jacobus [mailto:crispy_bird@yahoo.com]

Sent: Friday, June 20, 2003 2:30 PM

To: NIXON, Grant (Kanata); radsafe@list.vanderbilt.edu

Subject: RE: LNT and resources [Was: Scientific responsibility]





I am not aware of the limits you mentioned.  We have

several cyclotrons and produce routine PET imaging and

some "exotic" radionuclides for biomedical research. 

Most of our operations are automated.  From a

production standpoint I assume many of yours are. 

Again, I have never heard of medical research being

stopped because of safety/radiation cost.  Can you

provide an example?  Off-line if you wish.  I am

certainly interested.



I do agree that in your case, and ours, costs are

important.  In any regard, it is a case of capital

investments.  I think you would agree that the cost of

investments are different for production and research

operations.





--- "NIXON, Grant (Kanata)" <GNIXON@MDS.Nordion.com>

wrote:

> 

> My example is rather plain and the exposure rate

> limit and distance is the

> standard we must meet for a glove box. My company

> produces most of the

> world's demand for radioisotopes for nuclear

> medicine. Enough said.

> 

> You say that you have not "heard" of experiences

> such as these. All I can

> say is that it can happen, it does happen, and I

> have seen it happen. You

> simply were not privy to such experiences. What of

> it?

> 

> Note that regulatory limits apply to all aspects of

> the production and the

> accrued costs are anything but "chump change". The

> result is that some

> radioisotope technologies that may be better-suited

> for the task at hand

> cannot be brought to market.

> 

> We should try to stick to the facts at hand and not

> base counter-arguments

> on the lack of personal experience. Others are bound

> to have experiences

> beyond your own. One should simply do the

> (tangible/concrete) math for

> themselves.

> . . .



=====

-- John

John Jacobus, MS

Certified Health Physicist

e-mail:  crispy_bird@yahoo.com



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