Two-dimensional dose distribution of a miniature x-ray device for stereotactic radiosurgery

Med Phys. 1998 Jul;25(7 Pt 1):1212-6. doi: 10.1118/1.598298.

Abstract

The Photon Radiosurgery System is a miniature x-ray device developed for the treatment of small intracranial neoplasms. The x-rays are generated at the tip of a 10-cm-long, 3-mm-diam probe with a nearly isotropic distribution. Results from measurements of the two-dimensional dose distribution around the x-ray source are presented using two methods: (1) dose measurement with an ionization chamber and a water phantom system and (2) dose measurement with radiochromic film and a solid water phantom. The shape of the two angular dose distributions in the axial plane agree with each other to with approximately 10% and the dose at 10 mm from the source, orthogonal to the probe axis, was about 20% lower than at the same distance along the axis. The relative dose difference of 20% corresponds to a change in distance from the source of +/- 0.3 mm at 10 mm. It is shown that the anisotropy of radiation distribution in the axial plane can be improved to approximately 10% by adjusting the electron beam with a 12% reduction in the overall radiation output.

MeSH terms

  • Calibration
  • Dose-Response Relationship, Radiation
  • Miniaturization / instrumentation*
  • Phantoms, Imaging
  • Radiometry / instrumentation
  • Radiosurgery / instrumentation*
  • Water
  • X-Ray Film
  • X-Ray Therapy / instrumentation*

Substances

  • Water