12
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Monte Carlo aided dosimetry of the microselectron pulsed and high dose-rate 192Ir sources.

      Medical physics
      Brachytherapy, methods, Humans, Iridium Radioisotopes, therapeutic use, Mathematics, Models, Structural, Monte Carlo Method, Radiotherapy Dosage

      Read this article at

      ScienceOpenPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Despite the large number of single-stepping source pulsed and high dose-rate (HDR) remote after-loading devices in clinical use, the published literature contain little data characterizing dose-rate distributions around the high-intensity (4 x 10(3)-4 x 10(4) microGy m2h-1) 192Ir sources currently used in these devices. We have used the Monte Carlo method to calculate complete two-dimensional dose-rate distributions about the most widely used high dose-rate source design, as well as the Nucletron pulsed dose-rate (PDR) 192Ir source. A Monte Carlo photon transport code, incorporating the detailed internal geometry of the source, was used to calculate the dose rate per unit air-kerma strength in water medium on the transverse bisecting axis over the 0.15-12 cm distance range. In addition, polar dose profiles were calculated at distances ranging from 0.25 to 5 cm. The PDR and HDR dose-rate distributions are tabulated using the formalism endorsed by the Interstitial Collaborative Working Group and the AAPM Task Group 43, and includes dose-rate constant, radial dose function, anisotropy function, geometry function, and anisotropy factors. The dose-rate constants, lambda, of the MicroSelectron/HDR and PDR sources were found to be 1.115 and 1.128 cGy h-1 per unit air-kerma strength, respectively, in good agreement with previously published data for low dose-rate interstitial 192Ir sources. Oblique filtration by the high-density iridium metal core resulted in deviations from anisotropy as large as 35%-55% near the longitudinal axis of the source. Dose-rate distributions are also presented in Cartesian ("away" and "along") coordinates.

          Related collections

          Author and article information

          Comments

          Comment on this article