ANA Discussion Forum
Treatment Options => Radiation / Radiosurgery => Topic started by: mesafinn on March 21, 2013, 09:59:16 am
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I am wondering if anyone has read anything on the effectiveness/age of the particular GK equipment used if this option is chosen? My understanding is the "Perfexion" machine is the newest model, but has anyone come across any literature that discusses the actual equipment used in the process and what the benefits and/or risks are for a particular GK machine?
I think the older models might have the patient in the machine a bit longer (??), but I'm wondering if there's anything else one should consider?
Apologies if this has been discussed/processed elsewhere on the forum as I haven't come across anything yet.
A big thank you to this stellar community!
P.
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Cochlear radiation dose is reduced with the Gamma Knife Perfexion versus Gamma Knife 4C
The dose of radiation to the cochlear is related to hearing preservation.
Treatment times for Gamma Knife are largely related to the date of installation of the cobalt radiation source.
As the cobalt radiation source decays it gives off less radiation, resulting in longer treatment times.
I believe the cobalt radiation source is replaced every 5 years, and that treatment times will double in that 5 years
Setup times are reduced on the Perfexion, but treatment times are the same.
http://www.ncbi.nlm.nih.gov/pubmed/19494568
Here is a paper comparing the Gamma Knife 4C and Perfexion. Note the reduced radiation dose to the cochlear for AN's which shoild lead to better hearing preservation
http://www.ncbi.nlm.nih.gov/pubmed/19809786
Paper showing low cochlear dose is related to hearing preservation
http://www.ncbi.nlm.nih.gov/pubmed/18810212.
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As the cobalt radiation source decays it gives off less radiation, resulting in longer treatment times.
I believe the cobalt radiation source is replaced every 5 years, and that treatment times will double in that 5 years
That's about right.
Cobalt-60 has a "half life" of 5.26 years. "Half life" is the amount of time it takes a radioactive isotope to lose half its atoms to decay. After 5 years 8g of cobalt-60 would be only about 4g and emit only half the radiation, thus requiring twice the amount of time for the treatment.
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I agree w/the above responses.
One note: UPMC has both Perfexion and 4C models. When I was there in January for my GK, I requested the Perfexion unit for these reasons. Also, its said to be more comfortable. Their Perfexion unit was due to have the cobalt replaced and therefore I was told that the treatment would actually take 10-15 minutes longer than with the 4C. I went w/the Perfexion anyway, I slept thru most of it due to the IV sedation.