What are the disadvantages of calypso prostate radiation?

Expense: There are many machine types to give external radiation for prostate cancer. This is one of the newer ones to track and treat for movement. It is not really the standard of care but exceeds it for a cost. The best treatment in my opinion uses seeds and is only one day and costs far less. No need for tracking the prostate since the seeds move with and are in the gland.

MRI Distortion : Calypso is an excellent real time positioning system. It uses transponder beacons to communicate real time position of the target, currently approved for prostate cancer treatment. Disadvantage is that it distorts MRI images, so for my cyberknife patients which i treat in 4-5 fractions i get a fair amount of information from MRI and I use good seeds and image the organ about 120 times/ treatment.