Refering to Michaels post in another thread about Tomotherapy and conventional IMRT being compared to 2 similar high performormance sports cars was a great analogy. The fact that the FDA declared it "substantially equivalent" is the tip off here. They have to treat to margins with radiation just like surgery so even with daily adjustments, there is still healthy tissue damage. One CT is equal to 3 years of background exposure to ambient radiation (this months Cure magazine has a chart), I guess because of the extreme ionizing radiation that it isn't really an issue here but I personally am glad that my follow up scans are MRI's.
Beam entry points will take the same abuse irregardless of the 2 different (yet similar) systems.
If you REALLY want a unique treatment then consider if you are a candidate for PBT, which is stands for Proton Beam Therapy. There is NO tissue damage with this technology, which uses a charged particle concept instead of ionizing radiation (the charged particle reaches it full potential at the tumor itself). It is SO accurate that they give IMRT with it to provide safer margins. (Sorry Michael - I guess that means another trip to Loma Linda in So. Cal. or maybe I think there is one in Indiana) See
http://www.llu.edu/proton/ MDACCC thinks highly enough about it to invest 200 million in a special facility just for it.
One has to ask - is a daily CT REALLY necessary. They are just now discovering additional risks from x-rays that they didn't recognize before. Think back when they used to expose servicemen to atomic bomb fallout back in the 40's, not understanding the risks (they all died). We're still learning about radiation exposure.
Tomo sounds great on the surface but I rhink will take a few more years of data collection and experience in general use to determine and shake out completely all of the safety and efficacy issues.
It took the company 29 days to obtain FDA clearance. You can bet that the CT exposure issue wasn't even mentioned.
The comment by the doc at Hopkins is not specific enough. He mentions EBR which is generic for ionizing radiation in general. Most RO's will tell you that significanct salivary function can be saved with IMRT in general (I have at least 66% of my salivary function back). It's all about location. If you have a tonsil cancer you will lose the parotid behind the tonsil - it's unavoidable. They are simply too close together.
All medical devices are balanced out by risk/benefit and that is the bottom line. Medical devices that go the 510(k) route have minimal data for safety and efficacy. Now I'm going to ask my Physicist buddy in the Office of Device Evaluation at the FDA (who was probably the lead reviewer) if that was ever brought up as a consideration.
If there was truly a "major difference" then the FDA would have required a PMA and a LOT more science would have had to go into the submission. Other than that it reeks of marketing mumbo jumbo to me.
