Author Topic: Difference in types of radiation?  (Read 5771 times)

Tumbleweed

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Re: Difference in types of radiation?
« Reply #15 on: January 20, 2009, 03:28:17 am »
 I feel a little better now about my max. dose of 25GY.  I went back and read my notes to refresh my memory and they stated "a maximum mean dose of at 25GY at the center of the tumor".   I suppose now that is standard.  The maximum mean dose for the brain stem was 13.4 GY and the fifth nerve was 10.7 GY and 4.7GY. 

GK inherently delivers twice the dose of radiation to the center of the tumor compared to the amount that is delivered to the periphery. This is one of the main differences between GK and CK, as CK only delivers 15% greater radiation to the center of the tumor compared to the amount delivered at the periphery of the mass.

As for the brain stem and cranial nerves getting "dosed" as well: radiosurgery makes no effort to avoid important structures that are "in the way," as is the case when the tumor is wrapped around a cranial nerve or impinging on the brain stem. These important structures may be deliberately irradiated for no other reason than they couldn't be avoided because they were situated within the radiation "cloud" that had to be targeted on the tumor.

Best wishes,
Tumbleweed
L. AN 18x12x9 mm @ diagnosis, 11/07
21x13x11 mm @ CK treatment 7/11/08 (Drs. Chang & Gibbs, Stanford)
21x15x13 mm in 12/08 (5 months post-CK), widespread necrosis, swelling
12x9x6 mm, Nov. 2017; shrank ~78% since treatment!
W&W on stable 6mm hypoglossal tumor found 12/08

mk

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Re: Difference in types of radiation?
« Reply #16 on: January 20, 2009, 08:10:37 am »
Just wondering how one lists the "pros" and "cons" of each here when the hearing nerve or mask isn't so much of a factor.  Does one procedure tend to have more/different side effects?  What side effects have you experienced, if any, and were they severe enough to interfere w/ your everyday life?

Thanks,

Laura

Laura,

I recall reading a few times (I don't remember where) that when hearing is not an issue doctors who do both CK and GK will normally suggest a single dose procedure, since there is no hearing to preserve and single dose is more convenient. You may want to consult with the doctors on the Cyberknife forum about this.
CK and GK can cause pretty much similar side effects and from what I have seen on this forum there is probably no advantage of one over the other with regards to avoiding common problems like fatigue, diziness, swelling etc.

Marianna
GK on April 23rd 2008 for 2.9 cm AN at Toronto Western Hospital. Subsequent MRIs showed darkening initially, then growth. Retrosigmoid surgery on April 26th, 2011 with Drs. Akagami and Westerberg at Vancouver General Hospital. Graduallly lost hearing after GK and now SSD but no other issues.