INTERSTITIAL BRACHYTHERAPY FOR INTRACRANIAL METASTASES

In large medical centers, the availability of radiosurgery has relegat ed brachytherapy to a lesser role in the treatment of newly diagnosed solitary brain metastases. However, the treatment planning in radiosur gery is complex, and in some case the hardware is prohibitively expens ive; low or high dose rate brachytherapy requires only a stereotactic frame, commercially available software, and encapsulated radionuclides or newer tiny linear accelerators. Interstitial brachytherapy also re mains an option for the treatment of recurrent solitary metastases whe n other forms of treatment have failed. This article reviews the radio biology of low and high dose rate interstitial brachytherapy, the Univ ersity of California San Francisco (UCSF) results using iodine-125 imp lants, and early experience with the photon radiosurgery system (PRS) at Massachusetts General Hospital for the treatment of brain metastase s.