Evaluation of the accuracy of various dose calculation algorithms of a commercial treatment planning system in the presence of hip prosthesis and comparison with Monte Carlo

Mohammadi, Kheirollah; Hassani, Mohammad Amin; Ghorbani, Mahdi; Farhood, Bagher; Knaup, Courtney

doi:10.4103/0973-1482.204903

Cited by 15 publications

(15 citation statements)

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“…[9][10][11]14 Conversely, MC has consistently proven to be an accurate dose calculation algorithm in both homogeneous and inhomogeneous situations, particularly for patients with high-density implants. 9,[12][13][14][15] Our measurements with the hip prosthesis in the bolus phantom agree with previous studies as errors in Pinnacle approached 10% when density overrides were not used. Even with the densities of the bolus and prosthesis overridden in Pinnacle, the CCCS algorithm was only able to calculate the dose to the chamber within 4.4% accuracy.…”

Section: Discussionsupporting

confidence: 89%

“…Numerous studies have evaluated the performance of various treatment planning systems in the presence of metal hip prosthesis. [9][10][11][12][13][14][15] The collapsed cone convolution superposition (CCCS) dose calculation algorithm utilized by several treatment planning systems is accurate in homogeneous situations. However, when planning in regions near metal hip prostheses, the CCCS algorithm fails to accurately calculate dose.…”

Section: Introductionmentioning

confidence: 99%

“…Unlike CCCS, MC has been shown to accurately calculate dose in regions near high-density hip prostheses. 9,12 –15 True MC methods (ie, EGSnrc, MCNP, PENELOPE, etc) for patient dose calculations are computationally challenging to implement in the clinic, but some treatment planning systems have developed their own MC algorithms that can easily be used for patient dose calculations without the long computation times associated with true MC methods. Ade and du Plessis 9 studied the Monaco Treatment Planning System (ELEKTA), which uses an MC algorithm, demonstrating that it calculated dose within 4% of the measured dose in the presence of a hip prosthesis.…”

Section: Introductionmentioning

confidence: 99%

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VMAT Optimization and Dose Calculation in the Presence of Metallic Hip Prostheses

Parenica

Mavroidis

Jones

et al. 2019

Technol Cancer Res Treat

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Introduction:This research quantifies and compares the effect of hip prostheses on dose distributions calculated using collapsed cone convolution superposition and Monte Carlo (with and without correcting for the density of the implant and surrounding tissues). The use of full volumetric modulated arc therapy arcs versus volumetric modulated arc therapy arcs avoiding the hip implants (skip arcs) was also studied.Materials and Methods:Six prostate patients with hip prostheses were included in this study. The hip prostheses and the streaking artifacts on the computed tomography images were contoured by a single physician, and full volumetric modulated arc therapy arcs were created in the Pinnacle3 TPS. Copies of each plan were made, and the doses were recalculated with the densities of the prostheses and surrounding tissues overridden. The plans were then exported to Monaco and recalculated using a Monte Carlo dose calculation algorithm, with and without densities of the prosthesis and surrounding tissues overridden.Results:With density overrides, Pinnacle3 had a 4.4% error for ion chamber measurements. Monaco was within 0.2% of ion chamber measurement when density overrides were used. On average, when density overrides were used in Pinnacle3 for patient dose calculations, the planning target volume D95 value dropped from 99.3% to 82.7%. Monaco also showed decreased planning target volume coverage when plans were recalculated with correct density information. Full arc plans (with density overrides) for the patient with a bilateral prosthesis provided significant bladder sparing and some rectal sparing compared to skip arc plans.Conclusion:When planning for prostate patients with hip prostheses, correct density information for implants and surrounding tissues should be used to optimize the plan and ensure optimal accuracy. If available, a Monte Carlo algorithm should be used as a second check. Full arcs could be used to spare dose to organs at risk, while maintaining adequate planning target volume coverage, when using a Monte Carlo dose calculation algorithm.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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VMAT Optimization and Dose Calculation in the Presence of Metallic Hip Prostheses

Parenica

Mavroidis

Jones

et al. 2019

Technol Cancer Res Treat

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“…This study investigates that hip prosthesis creates considerable changes in the treatment planning of cervical malignancies like the similar study carried out by Mohammadi et al [24]. CCC algorithm is comparable with gold standard MC algorithm in terms of tumor coverage and sparing of critical structures except few parameters like volume of small bowel receiving 15 Gy dose and mean dose to femoral head.…”

Section: Discussionmentioning

confidence: 94%

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

Bhushan

Tripathi

Yadav

et al. 2021

J Egypt Natl Canc Inst

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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.

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“…Dose conformity assures the planner for better clinical outcomes. But, the introduction of any metallic object in the path of the beam has chances to deviate the doses from its original dosimetric values which was also reported by Mohammadi et al, (2017). The effectiveness of treatment depends on the plan made by the planner (medical physicist) and evaluated by radiation oncologist, for delivering optimum treatment to the patient.…”

Section: Discussionmentioning

confidence: 97%

Effect of Hip Prosthesis on Photon Beam Characteristics in Radiological Physics

Bhushan

Tripathi

Yadav

et al. 2020

Asian Pac J Cancer Prev

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Introduction: Aim of study is to investigate the effect of hip prosthesis on 6 and 15 MV photon beam energies. Materials and Methods: Prosthesis was kept at the level of tray position. The measurements were done on Varian Clinac-iX linac. Customized prosthesis, termed as Prosthetic Metal Implant (PMI) was made up of wrought austenitic stainless steel rod and covered with paraffin-wax. ‘Standard prosthesis’ was made up of wrought titanium alloy. The dose profiles were measured for three field sizes i.e. 5, 10 and 20 cm at 100 cm SSD for 6 and 15 MV energies. The perturbation index (PI) was also calculated. Results: Perturbation caused by standard prosthesis was approximately 50% higher than that of PMI. This result may be due to difference in dimension and not because of material composition. Variation of central axis dose might be due to the dimensions of PMI used for experiment which gave intermediate response (e.g. 102.1%, 141.0% and 117.7% for Open, Standard and PMI respectively for 10x10 cm 2 field size, 10 cm depth and 15MV photon beam setup )as compared to the ‘open’ and ‘standard’ prosthesis. Percentage dose at 10 cm for 6MV photon increased rapidly with field-size for PMI. But, for 15MV photon, difference was not significant. Surface dose (Ds) for PMI remains significantly higher for smaller field. Conclusion: The perturbation index varied from 0.05 to 0.22 for the measured energies and gave an idea to the planner to assess the behavior of the prosthesis. This range is applicable for both type of implants and for all clinical field-sizes. The attenuation caused by the prosthesis was significant and this effect should be considered in the treatment planning calculations.

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Evaluation of the accuracy of various dose calculation algorithms of a commercial treatment planning system in the presence of hip prosthesis and comparison with Monte Carlo

Abstract: Hip prosthesis creates a considerable disturbance in dose distribution which cannot be predicted accurately by the FFT convolution, CC, and superposition algorithms. It is recommended to use of MC-based TPS for the treatment fields including the hip prosthesis.

Cited by 15 publications

References 0 publications

VMAT Optimization and Dose Calculation in the Presence of Metallic Hip Prostheses

VMAT Optimization and Dose Calculation in the Presence of Metallic Hip Prostheses

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

Effect of Hip Prosthesis on Photon Beam Characteristics in Radiological Physics

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