A total of 109 patients were studied after receiving radiation therapy that included a dose to the spinal cord. In addition to irradiation of the primary site, 59 patients received radiation to the lower neck. Transverse myelopathy developed in three patients; all three had been treated with fields to the lower neck. The dose to the spinal cord at the site of junctional fields was thought to be considerably higher because of the beam divergence from multiple fields employed. The authors stress that prolonged fractionation of treatment, fixation of the head during treatment, precise dosimetry, and close surveillance of the patient are important factors in avoiding radiation myelitis. The authors also stress the importance of controlling divergence of multiple beams by employing appropriate shields.
Clinically significant spinal implants develop in intracranial ependymomas. Spinal subarachnoid implants developed in 11 of 32 patients who received local irradiation at the University of Michigan between 1955 and 1972 for intracranial ependymoma. Seven of these patients received spinal axis irradiation for neurological disturbances resulting from the implants, and implants were found in the other 4 patients postmortem. Ten patients had infratentorial tumors, and one had a supratentorial tumor; nine tumors were poorly differentiated, two were well differentiated. The authors conclude that spinal irradiation is required if the tumor is poorly differentiated, or located in the infratentorial fossa.
A stereotaxic radiotherapy technique that permits accurate delivery of highly localized dose to a small intracranial target has been developed. The technique facilitates precise integration of the diagnostic and therapeutic procedures including target localization, treatment planning, simulation, repetitive patient irradiation, and daily treatment verification. A conventional linear accelerator and computed tomography scanner as well as special diagnostic and therapeutic guides are used. A suitable dosimetric distribution is achieved using arc therapy with small radiation fields and 10-MV x rays.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.