RE: First neutron therapy procedure on the explanted human liver [FW]

["John Jacobus" <jenday1@EMAIL.MSN.COM>]

Jaro,

I am familiar with the BNCT process.  I believe it was first proposed in the

1950's.  As you mention, the Japanese have been working on this program for

a number of years, with a dedicated reactor to provide a collimated neutron

beam or reasonable size.  Again, I wonder about the medical risks associated

with this "plan."  I work a biomedical research facility, and we are very

sensitive to the claims and risks associated with human research.  (We do

not use the term human experimentation, but that is what it is.)



My point about the imaging of the metastatic sites is that it may be

inappropirate to claim success using a CT image.  The smallest volume you

could image is about 1mm.  However, surviving cancer cells could still exist

and proliferate.  Again, long term survival of the patient may not have been

their goal as much as validating the phyiological aspects of compound

labeling, uptake in the tumor cells, and successful treatment of the tumor

sites.



--- John



John Jacobus, MS

Certified Health Physicist

3050 Traymore Lane

Bowie, MD 20715-2024

jenday1@email.msn.com (H)



------------------

Jaroslav Franta wrote:



John,



I'm not sure "treatment plan" is the right description -- this is

experimental nuclear medicine - a clinical trial.



It doesn't seem strange to me -- the liver needs to be in the patient during

the boron compound injection, so that the boron gets into the liver and into

the cancer cells, and the excess may then be "washed away" from the rest of

the (healthy) tissue, so that its not damaged during the neutron therapy (

the tumorcidal result is caused by the reaction 10B (n,a) 7Li; the path

length of the alpha and lithium particles do not exceed 10 microns, about

the diameter of the typical cell, thus cell killing is localized i.e. death

of the cell where the reaction occurs.).

I'm not sure why they had to remove the liver -- certainly its easier to

irradiate a small, portable object, than to direct a neutron beam at a

specific part of the body.

But I'm sure that the latter would be the normal "treatment plan" once the

technique is proven.

It may be related to the type of irradiation facility available at that

research centre.... for instance, with glioblastoma (a deadly brain cancer),

if you don't have the right kind of neutron beam, you have to remove a part

of the skull, so that penetration is adequate without excessive irradiation

of surface tissues and bone -- this is the approach the Japanese have been

using with great success. But the trend now is to improve the beam quality

at research facilities (a specific, epithermal energy range), so that

surgery is not required.



I'm not sure I understand your second question, about "metastases in a

necrosis condition while the normal tissues appear well preserved." This is

the result you want - dead cancer cells and undamaged healthy cells ( I'm no

expert on this, but I believe those dead cancer cells are "removed" by

phagocytes....).

. . .



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