NOTE: When calculating dosimetry for COMS patients it is recommended you set the Calc. button in the Prescription window to COMS mode (or check the COMS calculation item in the Dose calc. options menu) and use Plaque Simulator's default I-125 (6711 COMS) isotope which has been preconfigured for source strength specification in air kerma strength, Sk, (U = cGy cm^2/hr) and for which the other functions have been assigned unity values.

The COMS (Collaborative Ocular Melanoma Study) dosimetry did not recognize isotopes other than I-125, nor did it recognize linear source geometry, anisotropy, or any of the other TG43 and Plaque Simulator dosimetry options. If COMS mode is enabled the dose calculation algorithm will conform to the COMS protocol. This protocol was modified in November 1996 to use a simplified form of the AAPM TG43 (Dosimetry of interstitial brachytherapy sources: Recommendations of the AAPM Radiation Therapy Committee Task Group No. 43, Medical Physics, Vol. 22, 1995) formalism.

  • TG43: D(r,o) = Sk * d * [G(r,o) / G(r0,o0)] * g(r) * F(r,o)
  • COMS: D(r) = Sk * d * (1/r^2) * g(r)

Dose calc. options | Guide Contents