Biomaterial Database

An adjustable collimator for stereotactic radiosurgery. 1992

P H McGinley, and E K Butker, and I R Crocker, and R Aiken

Emory Clinic, Division of Radiation Oncology, Atlanta, GA 30322.

Stereotactic radiosurgery utilizing a linear accelerator is now carried out using small non-coplanar beams to produce a high-dose volume that is approximately spherical in shape. It is desirable to shape the high-dose region so that it is similar to the target volume thereby reducing the amount of healthy tissue irradiated by a high dose. An adjustable collimator has been developed that can be employed to control the target volume height and diameter. Based on film dosimetry and measurements made with a small parallel-plate ionization chamber it was determined that the beams produced by the collimator have properties that make them suitable for radiosurgery. The basic dosimetry parameters (output factors and tissue maximum ratios, TMR) needed for patient treatment were evaluated. It was found that the diameter and length of the high-dose region produced by the patient rotation method are related to the light-field size at 100 cm from the x-ray target. A more favourable dose distribution was found for the adjustable collimator as compared to treating the same volume by use of the two-target method.

UI	MeSH Term	Description	Entries
D010315	Particle Accelerators	Devices which accelerate electrically charged atomic or subatomic particles, such as electrons, protons or ions, to high velocities so they have high kinetic energy.	Betatrons,Linear Accelerators,Accelerator, Linear,Accelerator, Particle,Accelerators, Linear,Accelerators, Particle,Betatron,Linear Accelerator,Particle Accelerator
D011879	Radiotherapy Dosage	The total amount of radiation absorbed by tissues as a result of radiotherapy.	Dosage, Radiotherapy,Dosages, Radiotherapy,Radiotherapy Dosages
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D016634	Radiosurgery	A radiological stereotactic technique developed for cutting or destroying tissue by high doses of radiation in place of surgical incisions. It was originally developed for neurosurgery on structures in the brain and its use gradually spread to radiation surgery on extracranial structures as well. The usual rigid needles or probes of stereotactic surgery are replaced with beams of ionizing radiation directed toward a target so as to achieve local tissue destruction.	Gamma Knife Radiosurgery,Linear Accelerator Radiosurgery,Stereotactic Body Radiotherapy,Stereotactic Radiosurgery,CyberKnife Radiosurgery,LINAC Radiosurgery,Radiosurgery, Gamma Knife,Radiosurgery, Linear Accelerator,Radiosurgery, Stereotactic,Stereotactic Radiation,Stereotactic Radiation Therapy,CyberKnife Radiosurgeries,Gamma Knife Radiosurgeries,LINAC Radiosurgeries,Linear Accelerator Radiosurgeries,Radiation Therapy, Stereotactic,Radiation, Stereotactic,Radiosurgery, CyberKnife,Radiosurgery, LINAC,Radiotherapy, Stereotactic Body,Stereotactic Body Radiotherapies,Stereotactic Radiation Therapies,Stereotactic Radiations,Stereotactic Radiosurgeries,Therapy, Stereotactic Radiation