Yesterday I had the first of five radiation treatments for my cancer.
A bit over a week ago, I lay down in what I gathered was basically a CAT scanner. I was lying on a couple of bags that they filled with, I guess, some kind of fluid that hardened, forming a kind of half cocoon which would keep me immobile during the treatments. They then did a scan to generate data that would be used to program the machine that would actually administer the radiation (something like an industrial robot capable of precise movements). Thursday was a “dry run” to make sure that the machine would perform as expected; then yesterday was the first actual treatment.
You don’t feel the radiation. The radiologist explained to me that the beam would have about the same power as a dental X-ray, but would take longer to administer the required dose. You just lie there relaxed and unmoving, except for normal breathing, for the fifteen or so minutes that it takes.
To mitigate the boredom, I mentally recited the lyrics to Gordon Lightfoot’s “Canadian Railroad Trilogy” and “The Wreck of the Edmund Fitzgerald”; and just as I was starting on “The Balad of the Yarmouth Castle”, they were done. I made it home in plenty of time to catch DW News on the PBS World Channel. 😎
I’ll have four more treatments, Monday through Thursday; then I’ll start chemo on the 6th.
The radiation machine (I should probably ask what the correct term for it is) was interesting. The radiation is generated by a roughly disk shaped thing with about an eighteen inch diameter, maybe a bit more, that looked something like this [from Wikipedia] although the rest of the machine was quite different. Opposite that is a flat thing that, I guess, notes where the other side of the beam is to provide feedback for proper aiming. The whole thing rotates around you, presumably to zap the cancer from different angles so that they don’t kill the tissues that you want to still be hanging around. 😎
Inside the disk were pairs of pointy things that were about 1mm or so apart. I had guessed, probably incorrectly, that the “antenna” is actually the space between the points. There were maybe ten or fifteen pairs, all in slightly different positions so that they would be slightly out of phase with each other, giving more precise control over the directionality of the beam. This whole paragraph could be way off the mark, though, if the radiation’s wavelength is in the millimicron range, which is what I get from the Wikipedia article. I’ll have to ask for a more detailed explanation of what’s going on next Monday, not because I have any desire to practice medicine without a license 😎 , but because I’m a geek who’d find it interesting.
Yeah the rotating is to minimise the spill over to the surrounding healthy tissue. Back in the early 1980’s when my mum had ratiation treatment they didn’t have such good control and her skin got burnt – like a bad sun burn, so the tecnology has come a long way.
I don’t think I’ve said – I hope the treament is successful, and that you get to go to your meeting too. I’ll add that I hope the side effects are minimal.
I echo Jazzlet’s sentiments for an easy treatment with few side effects.
Thanks for the support.
I’m definitely going to the C++ standards committee meeting in November. It’ll separate the third and fourth rounds of chemo by more than what’s optimal, but the oncologist says that he can work with that, although he’ll want to give me another CAT scan when I get home.
At present, it looks like “cure” is somewhere around a 90% probability. I lucked out because small cell lung cancer doesn’t usually present itself in an early stage. The flip side of that coin is that there are relatively few data points about how well radiation and chemotherapy work on my particular cancer, so the cure probability is really just a guess.
I think you’ve made the right call in pursuing this path of treatment and I wish you all the best of luck.
Another friend of mine had radiation therapy for breast cancer and had a target tattoo’d on her (for reasons!) that the used to show off as her “$200,000 tattoo.”
The picture you link to is a “linac” (linear accellerator).
A machine with a C-shaped arc with a radiation source at one end and a flat panel (the digital detector) on the other end is more like a “normal” x-ray machine.
X-rays are generally made by having electrons slam into a tungsten target.
The electrons are created by thermionic emission and a significant voltage (40–100 kV for imaging, not sure how much is used for treatment) is used to accellerate them into the target.
I suspect that the “pairs of pointy things” you saw are the lead strips that are part of the so-called collimator or beam-shaper. The shape of the opening can be adjusted to only irradiate the tumor as far as possible.
By irradiating from different directions only the tumor that is located in the intersection of all the beams gets a harmful dose, while the rest of the tissues that the beam passes through get a much lower dose.
rsmith @5: thanks for the information. I have a better understanding of the process now.