Brain and Spinal Cord
Arteriovenous Malformations (AVMs)
Arteriovenous malformations (AVMs) are defects of the circulatory system. They are generally believed to arise during embryonic or fetal development or soon after birth. They are comprised of snarled tangles of arteries and veins. Proton radiation has been used successfully for many years to treat these and other processes. Rates of complete obliteration three years following treatment approach 80-85 percent for small AVMs. Success rates are lower for larger lesions. Multi-modality treatment, including embolization and/or microsurgery, can bring cure rates to about 75 percent, even for some very large AVMs.
Isolated Brain Metastases
Proton radiation therapy is used to relieve symptoms from isolated brain metastases. A high dose of radiation can be delivered in a few treatments, sufficient to reduce symptoms and improve quality of life.
Pituitary Adenomas
At present, microsurgery is the treatment of choice in managing this disease. Success rates with surgery in micoadenomas (tumors less than 1 cm in diameter) range from 70 to 90 percent, but are much lower for larger tumors. These adenomas typically need additional treatment after surgery to achieve cure or prevent recurrence. Radiation with photons and charged particles, such as protons or helium ions, has been used successfully in the past. More recently, pituitary adenomas have been treated with stereotactic radiotherapeutic approaches such as single-dose radiosurgery with the "gamma knife" or linear accelerator.
At Loma Linda University Medical Center we have used the proton beam for focal irradiation of pituitary adenomas since 1990. We have pursued high-precision fractionated radiation therapy as opposed to single-dose radiosurgery. This may be a more reasonable approach in cases where the target volume is larger than 1 cm and the tumor is adjacent to vital structures.