Proton Stereotactic Radiosurgery (PSRS)
Small targets that tend to be spherical can be effectively treated using gamma or x-ray radiosurgery. However, with larger and more irregularly shaped targets, it becomes increasingly difficult to deliver a uniform dose of radiation within the target and spare surrounding normal tissues. In this circumstance, the unique characteristics of proton radiation are a significant advantage for performing radiosurgery.
|A patient lying in a high-precision robotic bed used for stereotactic radiosurgery.|
Proton stereotactic radiosurgery is offered for the treatment of a variety of tumors and malformations. Some of these include:
- pituitary adenomas
- acoustic neuromas
- cavernous sinus tumors
- arterial venous malformations (AVM)
The dose uniformity of protons is especially attractive for the treatment of AVMs as these malformations are not solid tumors but rather a tangle of vessels and normal brain. This means that when targeting an AVM it is impossible to avoid the normal brain contained within the malformation. A uniform dose means that there are no “spikes” of excessively high dose within the target. In some limited circumstances proton stereotactic radiosurgery can be used for lesions that are not contained within the head.