Subject: Re Radiotherapy hazards...... (fwd)
Date: Fri, 24 Jul 1998 100217 -0500 (CDT)
From: "Roy L. Beavers" <rbeavers@llion.org>
To: emfguru@hotmail.com
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....Something here that may be of much value to our scientists......
....Of interest to many of us....guru.....
---------- Forwarded message ----------
Date: Fri, 24 Jul 1998 09:29:25 -0600
From: "Bill P. Curry"
To: "Roy L. Beavers"
Subject: Re: Radiotherapy hazards......
Roy,
Though I am no expert on this subject, I suspect the problem here is that
conventional radiotherapy floods the cancer and adjacent healthy cells with
ionizing radiation which is generated by either a direct electron beam from a
linear accelerator or else an x-ray beam produced by allowing the electron
beam to strike a thin metal foil. (Descriptions of conventional radiotherapy
devices can be found in the book Medical Electron Accelerators by Karzmark,
Nunan, and Tanabe - McGraw Hill, 1993.) In my opinion, the hazards of using
radiotherapy as a post-operative procedure would be greatly mitigated if the
radiation pattern were confined to the cancerous tissue, and that can be done
(for some types of tumors) by a new therapeutic device which has recently been
put on the market.
Before I tell you more about this device, let me say that I know the number
two man in the company that produces this device, and I have a small amount of
stock in the company. With that in mind, you can judge for yourself how to
take my remarks.
The company is Photoelectron Corporation in Lexington, Mass. Their product
is a small portable low energy x-ray generator that is housed in a glass tube
about the size and shape of a veterinarian's hypodermic syringe. I have seen
the device when I visited them, trying to solicit them as a consulting client.
I have also read articles about their product and its applications in
professional journals. The barrel of this "hypo" contains all the high
voltage circuitry on miniature PC boards, and the "needle" is really a small
electron gun. At the end of the needle is a target of proprietary design that
emits x-rays in a precisely controlled pattern, so that one can choose how
large a region to irradiate and control this irradiation by controlling the
electron beam current and the accelerating voltage for the electrons. All the
cable connections from the outside world to this device are low voltage (in
fact battery powered) connections, so the patient is not exposed to any high
voltage hazard. High voltage for the electron gun is generated within the
hermetically sealed device by a series of solid state voltage multipliers
based on the principles discovered by Cockcroft and Walton (used extensively
in particle accelerators). The maximum voltage is about 40 kV.
In practice (for the treatment of brain tumors) the device is mounted in a
stereotactic rig, so that it can be guided into position along the same path
as was used by the biopsy needle, as soon as the tumor has been pronounced
malignant. The device is left in place about 30 minutes, and the tumor is
flooded with low level x-rays delivered to a precisely controlled region.
Then, the needle is withdrawn. Since the target design permits slightly more
back-emitted than forward-emitted radiation, any cancerous cells which might
adhere to the needle are destroyed - otherwise, the withdrawal process would
spread the cancer.
I really believe this device will eventually make a major impact on cancer
treatment options, though it will take some time to develop all the ancillary
treatment techniques for the various tumors for which the technique will prove
to be suitable and to have the procedures approved by the FDA. To those
physicians on the EMF list, I would like very much to have your opinions about
this type of cancer treatment. Articles about this technique have appeared in
the journal Medical Physics, as well as in other journals. (I don't know
whether there have been any articles in JAMA, but I think there have been
articles in journals devoted to oncology.) Also, much of the relevant
technical information can be obtained from the company's patents, some of
which I have examined.
After 6 years of clinical trials at Mass. General Hospital, the FDA approved
this device and the associated radiotherapy technique for treatment of
metastatic brain tumors. The company is developing and seeking approval for
other types of tumor treatments based on this technique, as well. Eventually,
this type of treatment will (hopefully) be available for lung cancer, breast
cancer, prostate cancer, etc.
--
----
Bill P. Curry, Ph.D. |Physics is fun.
EMSciTek Consulting Co. |Trying to make a living!
22W101 McCarron Road, |Phone: (630) 858-9377
Glen Ellyn, IL 60137 |Fax: same, but require prior notice
Home page: http://www.EMSciTek.com
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Reprinted with permission of Roy Beavers, http://www.feb.se/EMF-L/EMF-L.html