Author Topic: I AM NEWLY DIAGNOSED  (Read 8059 times)

Mark

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Re: I AM NEWLY DIAGNOSED
« Reply #15 on: August 14, 2007, 12:12:21 am »
I would tend to disagree somewhat with Steve's assertion that accuracy in radiosurgery is overblown. First, I wouldn't even try to compare the rigors of surgery with it and certainly some of the stresses of physical removal ( tugging) account for the long term dysfunction of the facial nerve or hearing preservation even when the surgeon says they didn't "cut" the nerve. While I agree that radiation isn't so precise as to be 0% at the edge of a tumor, the amount of "spill over" to healthy tissue with 1 mm accuracy vs. 2 mm can be significant. An integral part of this point is how well the machine conforms to the irregular shape of the tumor. the better it conforms, the better spreading of the dose to the tumor and minimizing of exposure to healthy tissue. AKA accuracy  :). this is an aspect that CK does excel over GK and that both radiosurgery machines do over their radiotherapy counterparts such as trilogy and Novalis.

Mark
CK for a 2 cm AN with Dr. Chang/ Dr. Gibbs at Stanford
November 2001

Mark

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Re: I AM NEWLY DIAGNOSED
« Reply #16 on: August 14, 2007, 08:51:55 am »
Hi Bruce,

Re: Fractions vs. One shot accuracy. Your point is absolutely correct in the case of most of the LINAC machines which are classified as radiotherapy. Their lesser accuracy and the challenge of consistently repeating the same mask placement each treatment is the main reason that treatment plans are for very low doses over 25-30 days. This approach actually delivers a larger cumulative GY dose than GK / CK do in the one shot or 3 fraction higher dose protocol. CK would be the exception to the repetitive accuracy issue since it is the only machine that actively targets the tumor during treatment. The trade off one could argue is that there is additional X-ray exposure in this process.

Mark
CK for a 2 cm AN with Dr. Chang/ Dr. Gibbs at Stanford
November 2001

 


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