All brain tumor patients would prefer a form of radiation that deposits most of the radiation at the brain tumor site, without affecting the tissue around it or behind it. Proton Beam or Proton Therapy is rarely mentioned by doctors as a treatment for the acoustic neuroma (vestibular schwannoma) but proton therapy researchers claim it does not intensely radiate the tissue along the path and it does not radiate the tissue behind the tumor at all.
Please take note of a recent article in The Washington Post called: "How proton therapy attacks cancer. These once-exotic weapons in the cancer-fighting arsenal are getting faster, cheaper and more common" By Bonnie Berkowitz and Aaron Steckelberg, Updated March 5, 2018. It provides a really good description of how Proton Beam works, including a great graphic image. You can read how with Proton Therapy, a beam of PROTONS is aimed at the tumor and how the beam, controlled by magnets, deposits most of the radiation at the tumor site without affecting most of the tissue behind it. This is different from photon radiation, where the beam of photons is aimed at the tumor and it irradiates all tissue along its path relatively equally, including healthy tissue behind the tumor. (Examples of Photon radiation include: Cyber knife, Gamma Knife and other traditional radiation).
Critics of Proton Beam radiation express concern that some of the healthy tissue gets irradiated with Proton Therapy. To understand this issue, look online for publications about the topic called "Proton Beam Range Uncertainty." There is a 2012 presentation published by Harald Paganetti, PhD, the Director of Physics Research, Massachusetts General Hospital, Department of Radiation Oncology. Upon inquiry, in an e-mail response, Dr. Paganetti stated that it is true that predicting the correct range of proton beams in patients is subject to uncertainties. He said that his group, amongst others, has been doing research on this subject for many years. Having said this, because there are uncertainties in predicting the range to within mm accuracy, he said that they do add additional margins to the tumor. He said, that with Proton therapy they do treat additional healthy tissue to make sure that the tumor is always covered. So, while range uncertainties are of concern for acoustic neuromas, and other tumors, he said that they do this to ensure that tumor coverage is not compromised. He said his research group tries to reduce range uncertainties so that they can reduce those margins and thus reduce the amount of normal tissue being irradiated and to reduce potential side effects. The last thing he stated really stood out: He said "Note that the dose outside of the target is typically much higher with conventional photon treatments as compared to proton treatments."
To gain more knowledge, research and read here:
https://www.ncbi.nlm.nih.gov/pubmed/?term=proton+beam+radiation. The author contact information for each study is available. Acoustic Neuroma patients really should be asking questions and probing deeply into the subject of Proton Beam radiation, in order to achieve truly informed consent.
It is possible to send your MRI of the brain to Proton Therapy Centers and to get a response from the staff about whether Proton Therapy would be helpful for you, while only incurring the cost of shipping the MRI. Depending on your diagnosis, Proton Therapy treatments may be the optimum solution to arrest the growth and/or to reduce the size of the acoustic neuroma. Proton Therapy is a life-saving method used to treat children with cancer and it may be challenging for adults with acoustic neuromas to gain access to proton beam treatment, because there is such high demand for it and because other solutions seem more readily available and perhaps provide quicker treatment. The good news is that now there are many new Proton Centers being constructed. A list of the centers is usually updated by the National Association for Proton Therapy (NAPT). Until future developments unfold that perhaps offer nanotechnology and/or other treatments, it seems likely that in the near future, more acoustic neuroma patients will routinely seek more information about getting Proton Beam radiation treatment by those who have clearly mastered the art of planning the Proton Therapy treatments.
