Hi Katrider,
"welcome" to the AN club. If you are considering radiosurgery for the treatment of your AN, the choice of machine and protocol ( FSR vs. one dose) are important considerations. The doctors you have consulted with are probably promoting the Novallis machine because it is what they have in the hospital. Reality is that Novalis is significantly less accurate than GK or CK and is considered a radiotherapy platform instead of a radiosurgery machine for that reason. Accuracy is +/- 2.5 mm whereas GK is a little over 1mm and CK is .89 based on studies.
I'll attach some exchanges between patients and the doctors who volunteer on the Cyberknife support group site
Mark
Posted 1/11/2007 7:49 PM (GMT -8)
Could I get some information regarding the benefits of Novalis vs. Cyberknife for a AN of approx. 1.9 cm. The last doctor I saw touted the benfits of Novalis over Cyberknife, and now I feel a bit confused!
Posted 1/13/2007 7:47 AM (GMT -8)
Novalis is an accelerator based system that achieve accuracy of about 2.5 mm. We don't feel that is accurate enough for critical brain work, although it is often used that way. You have to decide for yourself whether to accept the lower accuracy (compared with 0.89 mm for CyberKnife). In other words, they could either miss 2.5 mm of tumor (13% the diameter of your tumor) or treat 2.5 mm of brainstem, cochlea, or other critical structures.
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Clinton A. Medbery, III, M.D.
St. Anthony Hospital Cyberknife Center
(405) 272-7311
buddy@swrads.org or cmedbery@coxinet.net
and another
Posted 11/29/2006 9:52 PM (GMT -8)
CK and GK have similar accuracy for intracranial tumors. Ck avoids the use of a frame that must be screwed to the skull for several hours and also allows for fractionated treatment which may be important in some cases. Novalis is less accurate and is not a dedicated radiosurgery machine.
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Clinton A. Medbery, III, M.D.
St. Anthony Hospital Cyberknife Center
(405) 272-7311
and finally
Posted 11/29/2006 9:07 AM (GMT -8)
Dr(s) Spunberg and Medberry,
On the CK Society site there is a comparison of various machines and comments are made regarding the pros and cons. Specific to Novallis it is indicated that on a one dose protocol with the head frame that Novallis "approaches but does not meet the accuracy of either GK / CK". I am aware of the Stanford study which shows that CK is equal to slightly more accurate than GK and I know from previous posts that both of you gentlemen feel that the difference is not significant between those two machines. If anything the advantage of CK is the ability to fractionate treatments and avoid the headframe. Can you point me to some studies which support that Novallis is less accurate than the other two for cranial tumors , specifically AN's. beyond that based on your knowledge and experience with these machines can you offer some compelling reasons why you would steer patients away from one machine to the other. While I would assume the Novallis machine is certainly adequate for this treatment, I have always been under the imprssion that either GK or CK would be preferable due to increased accuracy.
Thanks
Mark
Posted 11/29/2006 3:26 PM (GMT -8)
Look no further than the Novalis website. Their own data shows a BEST accuracy of about 2 mm. Depending on the size of the AN, that could be a substantial fraction of the tumor size. In other words, with a 6 mm tumor, you could miss one-third of it with Novalis. Actual accuracy in general use may be worse than 2 mm, since that is the best. Compare that to CK (0.89 mm very repeatable) and GK (probably 1-2 mm total accuracy).
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Clinton A. Medbery, III, M.D.
St. Anthony Hospital Cyberknife Center
(405) 272-7311
buddy@swrads.org or cmedbery@coxinet.net