Application of a Monte Carlo‐based method for total scatter factors of small beams to new solid state micro‐detectors

Abstract

The scope of this work was to apply a method for estimation of total scatter factors of the smallest beams of the Cyberknife radiosurgery system to newly available solid‐state detectors: the PTW 60008 diode, the SunNuclear EdgeDetector™ diode, and the Thomson and Nielsen TN502RDM micromosfet. The method is based on a consistency check between Monte Carlo simulation of the detectors and experimental results, and was described in a recent publication. Corrected total scatter factors were in excellent agreement with the findings of the former study. The results showed that the diodes tend to overestimate the total scatter factor of small beams, probably due to excessive scatter from the material surrounding the active layer. The correction factor for diodes and for the micromosfet, however, was found to be independent of the electron beam width. This is a desirable characteristic because it allows standard correction factors to be used for treatment units of the same type, without the need of case‐by‐case Monte Carlo simulation.PACS numbers: 87.55.kh; 87.55.ne; 87.56.Fc.

A comparative study of small field total scatter factors and dose profiles using plastic scintillation detectors and other stereotactic dosimeters: The case of the CyberKnife

“…These two parameters were adjusted by Araki by fitting measured and simulated off-axis dose profiles and central axis depth-doses. In the second Monte Carlo study, which is separated in two different papers, Francescon et al 5,36 developed a method to determine these two parameters for any Cy-berKnife system from measured tissue-phantom ratios and total scatter factors with some specific dosimeters. This method was applied in the present work to determine these parameters for our specific CyberKnife system.…”

“…Francescon et al 5,[36][37][38] modeled ten commercial detectors to determine correction factors (k f clin , f msr Q clin , Q msr , Eq. (1)) for the three smallest cones.…”

Small field dosimetry: What have we learnt?

“…Francescon et al (27,35,39) provided detailed information on kΩ factor variability for multiple linear accelerator and detector configurations down to a field size of 5 mm square. Similar data has been also been reported by other groups (16,19).…”

Influence of smoothing algorithms in Monte Carlo dose calculations of cyberknife treatment plans: A lung phantom study

“…[1,2] There are several algorithms introduced to improvize the dose calculations in a heterogeneous interface or medium. [3][4][5][6][7][8] The Monte Carlo algorithm is considered to be the finest dose calculating algorithms among all other commercially available algorithms. [9,10] Multiplan (Accuray Inc., Sunnyvale, CA, USA) TPS is one among the treatment planning systems that uses the Monte Carlo dose calculation algorithm.…”