Cancer Update

December 18, 2012

Today we had a visit with Dr. Hitchcock and her resident, Dr. Brandi Page.  The purpose was to determine if radiation will be a reasonable option to deal with the largest tumor in my lungs, which is adjacent to the major air passage into my left lung.  If it grows much more, it will begin to impact my breathing.  they don't think that would be very good.  There is another fairly large tumor nearby, and they think they can get both of them with the same treatments, so we agreed.  The next step is to go in for my tattooing, and schedule the treatment times.   The tattoos I got last time will not work this go around; no need for the mask to hold my head in place, instead I get a straightjacket and their reference marks have to go in a different place.  The tattoos are very tiny, but I think I will request an airplane, a bear, and a heart.  I hope they do a better job than last time; it is hard to make out the sailing ship, dragon, and "Mother" they gave me.
They think it will take 15 shots to do the best job.  They do not expect the radiation to completely eradicate the tumors, but it will likely shrink them so that they will not be a problem for the remaining time that I have, whatever that turns out to be.  These treatments will take place 5 days a week for three weeks, and will likely begin the day after Boxing Day.
I had assumed they would use Intensity Modulated Radiation Therapy like they did on the parotid gland.  As usual, I was wrong.  They said that IMRT would expose too much of the lung tissue to radiation, and the lung can't take very much radiation.  They will use 10 MeV photons in a straight path through tissue that will be able to withstand that level of radiation and will shoot from the front as well as the back. (Note:  MeV - Million electron Volts - the energy an electron will have after being subjected to an electric field of 1 million volts.) There appears to be a choice of 5, 10, or 15 treatments.  Dr. Hitchcock did not say it, but I assume that the 15 treatment option will decrease the amount of radiation in any given session, thus reducing the potential damage to surrounding tissue.
I also learned that the medical community has its own definition of X-rays and gamma rays.  When I was in college, I understood the difference between the two was the energy:  X-rays are a step above ultra-violet light in terms of frequency and energy, gamma rays are the next step, being at the high end of the electromagnetic spectrum.   On the other hand, the medical community prefers to define gamma rays as coming from a nuclear event (positron annihilation, nuclear decay, etc.).  X-rays are created from some other event, like an atomic process where an orbiting electron changes state, or is accelerated like in a cyclotron.  This definition puts gamma rays into an energy range from a few KeVs (yes, even in the ultra-violet range) to a few MeVs, whereas X-rays from accelerators or sources other than nuclear decay can be of just about any energy including 10 GeV and above.  So, as I asked questions, we talked past each other for a while, because I was talking Physics terminology and she was talking medical talk.  After the session, I looked it up.  Like most things in life, the subject is complicated, and the above explanation does not do it justice, but will have to suffice for now.