It has been awhile since I've signed on. I've read many entries though, and feel for everyone touched by this horrible disease.
Dennis recently had a PET that detected an area approximately one inch below his initial tumor. When he saw the ENT, he immediately scheduled a biopsy that will be done on Monday.
My question would be, does anyone know the limit of radiation? Would one inch possible leave enough of a margin for re-radiation to be an option?
Thank you all in advance.
Love,
Mandi

I think that Gary should answer this question. In the most general terms, tissues can only recieve a certain amount of grays of radiation then the radiation can cause new problems such as necrosis, loss of vascularization and more. There is also the issue of total accumulative grays that your body gets no matter where you are radiated. There is a maximum liofetime dosage. Given the precise nature of IMRT technologies and seeing the very fine definitions of it that can be used in brain cancers, a measurment as long as an inch seems like a mile to me. But there is still some scatter radiation to surrounding tissues. I will leave a specific answer to your question to Gary who comes from a radiaology background.

Mandi,
first of all I am not a radiation oncologist but I will try to help with your question. In my case (IMRT) we had to widen the irradiation volume after the first 3 radiation. At that point they had to recalculate the new radiation schedule (positions/intensity, profile) taking into account what happened before.

I am assuming that you had IMRT previously. Are you still in contact with that place?
Each tissue and structure has different limits and sensitivities for radiation. Whether they can use radiation again depends amongst many other things what happened to THAT tissue during previous radiation. Specifically, how many grays did that tissue get. That depend on the protocol they used and should be documented.

I found a link that might be helpful in getting a glimpse of what is going on. (I am not claiming this is a particularly good article, I cannot judge that, it was just handy)
Read especially p 210

http://www.medicalphysics.org/apps/medicalphysicsedit/Ch_10_Ling.pdf

Hope that helps, you should talk with the RO you had for your last treatment.

Markus

Dear Brian and Markus,

Thank you both for your informative and caring responses.

Markus.....the link you sent is so informative. Thank you so much for your time and effort.

Brian.....You continue to astound me of what a caring and tolerant boardmaster you are. You know I'm a long standing pain-in-the-butt, but you continue to extend your knowledge to me. Thank you.

I sit and pray that I will have another 5 years with Dennis, but reality tells me differently. There is nobody close who will discuss what the outcome may be, so I turn to you.

Thank you for being here, and I will continue to let you know of our progress...........

Love,
Mandi