Thanks Dr. Z!
I'll add the comment that "LDR" and "MDR" are low and medium dose rate machines. NRC has published some licensing and inspection guidance on the dose rates that defined the low, medium and high types but I can't put my paws on it right now (and I work here!). I think it was in the Inspection Procedures 87100 or 2800. Maybe Greg Sackett or one of the "Staties" has it handy.
Maybe someone with Euro experience can provide additional comment on this thought. I've heard that HDRs (or LDR, MDRs) are the only method of brachytherapy permitted in France because of the low occupational exposures from this technology. True, false. part true, part false?
Jim
jhm@nrc.gov
>>> Rachid Zitouni <azittouni@yahoo.com> 08/19 7:46 AM >>>
Rather well done!
It is also worth mentioning that, while the technology has improved
quite a bit bringing more advantages and comfort to the patient, other
parameters of importance are also crucial in brachytherapy. For
example, the radiation treatment protocol which is closely related to
cell survival, tissue recovery,... and other physiological constraints.
LDR and MDR are still of good use! Anyway, a lot of research work in
this field is being pursued at some of the most prominent institutions
and it is hoped that the advancement of technology will be followed by
pertinent cancer research results.
Regards,
Dr. Abderrachid ZITOUNI, PhD
azittouni@yahoo.com
-- James Myers <JHM@nrc.gov> wrote:
> Ron,
>
> This is a very simple, I hope, explanation. (If
> not, I'm sure I'll hear about it!)
>
> The high dose rate afterloaders (HRDs) are used to
> treat cancer. There are several manufacturers and
> there has been a couple design variations over the
> years. Essentially, they store the radioactive
> source in a "safe" within the machine. Catheters
> are placed into the tumor according to a treatment
> plan and are connected to the afterloader by guide
> tubes. The afterloader's computer pushes a source,
> usually about 10 Ci of Ir-192, on a drive cable
> through the guide tube and into the pre-placed
> catheters and retracts the source when the treatment
> plan is completed. Some HDRs can cycle the source
> between several catheters during a single treatment.
> A single treatment takes only a short time due to
> the high dose rate from the source. Usually the
> treatment is delivered in "fractions" over several
> days.
>
> Advantanges over the old "manual" brachytherapy
> technique.
>
> High dose rate delivered in fractions directly to
> the tumor (or very close to it).
> Fast treatment time
> Precise dose delivery and execution of the treatment
> plan
> Higher patient throughput due to decreased treatment
> time
> Mobility....small size lets it be put on a vehicle
> and taken to different use locations so more
> patients can be treated over a larger geographic
> area
> Low exposure to operators since its operated
> remotely!!!!!!!
>
> Disadvantages
>
> Complex machine that requires special training and
> experience to use it effectively and safely and like
> everything....its subject to operator error and
> mechanical problems from time to time.
>
> Personally, I think HDRs are neat machines and
> provide lots of benefit to patients and workers over
> the old manual methods. Hope this helps and I'm
> sure others will chime in with more detail.
>
> Just my opinion.....
>
> Jim Myers
> jhm@nrc.gov
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> !
> !
>
>
>
>
>
>
>
>
************************************************************************
> The RADSAFE Frequently Asked Questions list,
> archives and subscription
> information can be accessed at
> http://www.ehs.uiuc.edu/~rad/radsafe.html
>
__________________________________________________
Do You Yahoo!?
Bid and sell for free at http://auctions.yahoo.com
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
!
!
!
!
!
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html