Dosimetric impact of FFF over FF beam using VMAT for brain neoplasms treated with radiotherapy

Abstract

Background: This study was conducted to assess the dosimetric impact of FFF beam plans on high-grade brain neoplasms using the VMAT technique when compared with FF beam plans. Material and Methods: Thirty patients with high-grade brain neoplasms, who had received radiotherapy using VMAT technique retrospectively were selected for this study. All the patients were planned for VMAT using 6MV_FF beam and the same plan was re-optimized using 6MV_FFF beam keeping the same dose constraint. Radiotherapy dose distribution on planning target volume (PTV) and organs at risk (OAR), target conformity index (CI), Homogeneity Index (HI), Low dose volume in the patient (V5, V10, V20, and V30), and Integral dose to the whole body in both plans were compared. Results: The PTV coverage and OAR’s showed no significant differences in dose distribution between the FFF and FF beam VMAT planning. There was a reduction of the average maximum dose in the right eye, left eye, right optic nerve, and left optic nerve using FFF beams. The reduction in average low dose volume was observed in V5, V10, V20, V30, and Mean Dose. Also, a significant reduction was observed in the integral dose to the whole body using the FFF beam. Conclusions: Using FFF beams with VMAT is doable for the treatment of high-grade brain neoplasms, and the delivery mode of the FFF beam in VMAT may yield similar results to FF beam which should be confirmed in a large scale prospective clinical trial.

Dosimetric and Radiobiological Impact of Flattening Filter‐Free Beam and Dose Calculation Algorithm Using RapidArc Plans for Cervical Cancer Treatment

“…7,8 With these advantages of FFF beams, many researchers have studied the dosimetry of FFF and FF beams for various sites and showed a reduction in the mean dose to normal tissue, sparing normal tissue and OAR without compromising the target coverage. 9 Therefore, evaluation of the radiobiological parameters of a treatment plan using dosimetric parameters is a comprehensive and rational approach. Hence, the present study aims to quantify the potential ben-efits of the FFF beam and dose computation algorithms (AXB and AAA) on cervical radiotherapy using the RapidArc technique compared with the FF beam.…”

“…With these advantages of FFF beams, many researchers have studied the dosimetry of FFF and FF beams for various sites and showed a reduction in the mean dose to normal tissue, sparing normal tissue and OAR without compromising the target coverage 9 . Modern photon dose calculation algorithms are classified based on the complexity of the scattering model for photon and electron transport computations principally in a heterogeneous medium, and the calculation time.…”