Two Approximations to Obtain the Collimator Scatter Factor (Sc) for MLC Irregular Fields

[Approximation of collimator scatter factor Sc by a saturation model].

To more easily estimate accurate values of collimator scatter facor, S(c), we suggest a two-component saturation model that accounts for scatter from the primary collimator and flattening filter and from the collimator jaws. This model, which assumes an exponential distribution of scatter intensity, was tested by in-air measurements using a mini-phantom for 4 MV and 10 MV X-rays of a Clinac 210...

SU-E-T-21: Modeling a MLC Scatter Source for In-Air Output Factors.

PURPOSE Scattered radiation from multi-leaf collimators (MLCs) is no longer negligible for calculating in-air output ratio, Sc for small and irregular fields often used in intensity-modulated radiation therapy (IMRT). An extra-focal source model for scattered radiation from MLCs, namely MLC scatter source, has been developed to improve the accuracy of the Sc calculation. METHODS A conventiona...

Two Algorithms of Irregular Scatter/Gather Operations for Heterogeneous Platforms

Calculation the phantom scatter factor for the linear accelerators device

Introduction: In the last few decades, a lot of monte carlo codes have been introduced for medical applications. this is important because through simulation, we are fully independent of the spectral scattering factor that we are not able measure in real terms. The effect of the radiation energy, the dimension of the radiation field, the sensitive volume of the ion chamber on t...

SU-E-T-176: Improved Collimator Scattering Factor (Sc) Measurements for Small Fields Using Build-Up Caps in Robotic Radiosurgery.

PURPOSE The Monte Carlo calculation algorithm in the MultiPlan (Accuray, Palo Alto, CA) treatment planning system used for CyberKnife (Accuray) robotic radiosurgery requires in-air measurements. In this study, results were compared for the impact of build-up caps using a diode detector for small field in-air measurements. METHODS Two acrylic caps custom-made for the SFD diode detector (IBA, G...