Feasibility of Monte-Carlo algorithm in comparison with collapse-cone dose calculation algorithm of a commercial treatment planning system in the presence of high-density metallic implant: a dosimetric study

Abstract

Background The number of people with implanted hip prosthesis has grown worldwide. For radiotherapy planning of patients with hip implants, few main challenges are encountered. The aim of the present study was to evaluate the feasibility of different planning algorithms in the presence of high-density metallic implant in the treatment of patients with carcinoma cervix. Results It was found that D98% were 44.49 ± 0.11, 44.51 ± 0.13, 44.39 ± 0.22, and 44.45 ± 0.16 Gy for 4FMC6MV (4-field technique calculated with Monte-Carlo algorithm and 6 MV photon energy), 4FMC6MV_WP (4-field technique calculated with Monte-Carlo algorithm and 6 MV photon energy without prosthesis), 4FCC6MV (4-field technique calculated with collapse-cone-convolution algorithm and 6 MV photon energy), and 4FCC6MV_WP (4-field technique calculated with collapse-cone-convolution algorithm and 6 MV photon energy without prosthesis) respectively. Similarly, D2% were 49.40 ± 0.84, 49.05 ± 0.76, 48.97 ± 0.91, and 48.57 ± 0.85 Gray (Gy) for 4FMC6MV, 4FMC6MV_WP, 4FCC6MV, and 4FCC6MV_WP respectively. The present study has not suggested any major difference between the Monte-Carlo (MC) and collapse-cone-convolution (CCC) calculation algorithm in the presence of high-Z metallic implants. Volume of bowel receiving 15 Gy dose has shown a significant difference with prosthesis cases. This study investigates that hip prosthesis creates considerable changes in the treatment planning of cervical malignancies. Conclusion CCC algorithm is in good agreement with MC calculation algorithm in the presence of high-density metallic implants in terms of target coverage and avoidance organ sparing except few parameters.

Impact of Dose Perturbations Around Brachytherapy Seeds in External-Beam Radiotherapy Planning: A Fundamental and Clinical Validation Using Treatment Planning System-Based Monte Carlo Simulations

“…This may be attributed to the differences in the dose-calculation models, the uncertainty of film dosimetry, and simplifications assumed by TPS-MC simulations in terms of physical processes [ 19 , 24 ]. Certain reports on dose calculations in TPSs have shown that they can be performed accurately, including around high-Z materials [ 25 , 26 ]. However, these reports were based on large-volume high-Z materials and not on extremely small high-Z materials, such as the seeds used in this study.…”

To study the impact of different optimization methods on intensity-modulated radiotherapy and volumetric-modulated arc therapy plans for hip prosthesis patients

“…The material used for was “titanium”(composition: titanium 88.5%–91.0%; aluminum 5.6%–6.5%, vanadium 3.5%–4.5%, iron 0.25%, oxygen 0.13% and carbon 0.08%, average ED 3.74 relative to water; diameter of femoral heads of prosthesis ranging from 40 to 54 mm. [ 20 ] The thermoplastic cast was made for every patient. The acquired images were transferred to Varian Soma vision contouring stations.…”