Volumetric modulated arc therapy for prostate cancer patients with hip prosthesis

Prabhakar, R; Kumar, Mohan; Cheruliyil, Suja; Jayakumar, Silpa; Balasubramanian, Satheesan; Cramb, Jim

doi:10.1016/j.rpor.2013.03.006

Cited by 21 publications

(22 citation statements)

References 22 publications

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“…For each patient, 3 retrospective VMAT plans were created: (1) PA, (2) 2 full arcs optimized with a max dose constraint of 500 cGy to prostheses (MD), and (3) 2 full arcs optimized with a max dose-volume histogram (DVH) constraint of 500 cGy to 10% of the prostheses volume (MDVH). The dose constraint of 500 cGy is similar to the constraint utilized by Prabhakar et al 10 The PA technique was considered the gold standard for comparison, as this technique utilizes 6 PA with beam angles that avoid entering each prosthesis as recommended by AAPM Task Group 63. 3 A minimum gantry span of 40° was chosen for each partial arc.…”

Section: Methodsmentioning

confidence: 99%

“…However, instead of using the avoidance sector capability available, these authors chose to limit hip prosthesis entrance dose with the use of an avoidance optimization structure around the hip prostheses with 1 cm margin and a 500 cGy dose constraint. 10 Unfortunately, Philips Pinnacle version 14.0 (Philips Healthcare) treatment planning system has no easy way to add avoidance sectors in the plan to avoid prostheses entrance dose.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of VMAT Planning Strategies for Prostate Patients with Bilateral Hip Prosthesis

Xhaferllari

Liu

et al. 2021

Technol Cancer Res Treat

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Purpose: In this study, we investigate linac volumetric-modulated arc therapy (VMAT) planning strategies for bilateral hip prostheses prostate patients with respect to plan quality and deliverability, while limiting entrance dose to the prostheses. Methods: Three VMAT plans were retrospectively created for 20 patients: (1) partial arcs (PA), (2) 2 full arcs optimized with 500 cGy max prostheses dose (MD), and (3) 2 full arcs optimized with max dose-volume histogram (DVH) constraint of 500 cGy to 10% prostheses volume (MDVH). PA techniques contained 6 PA with beam angles that avoid entering each prosthesis. For each patient, other than prostheses constraints, the same Pinnacle VMAT optimization objectives were used. Plans were normalized with PTV D95% = 79.2 Gy prescription dose. Organ-at-risk DVH metrics, monitor units (MUs), conformality, gradient, and homogeneity indices were evaluated for each plan. Mean entrance prosthesis dose was determined in Pinnacle by converting each arc into static beams and utilizing only control points traversing each prosthesis. Plan deliverability was evaluated with SunNuclear ArcCheck measurements (gamma criteria 3%/2 mm) on an Elekta machine. Results: MD and MDVH had similar dosimetric quality, both improved DVH metrics for rectum and bladder compared to PA. Plan complexities among all plans were similar (average MUs: 441-518). Conformality, homogeneity, and gradient indices were significantly improved in MD and MDVH versus PA ( P < .001). Gamma pass rates for MD (99.0 ± 1.2%) and MDVH (99.2 ± 0.99%) were comparable. A significant difference over PA was observed (96.8 ± 1.6%, P < .001). Field-by-field analysis demonstrated 12/20 PA plans resulted in fields with pass rates <95% versus 1/20 plans for MD and none for MDVH. Cumulative mean entrance doses to each prosthesis were 62.9 ± 17.7 cGy for MD plans and 83.4 ± 27.5 cGy for MDVH plans. Conclusion: MD and MDVH plans had improved dosimetric quality and deliverability over PA plans with minimal entrance doses (∼1% of prescription) to each prosthesis and are an improved alternative for bilateral prostheses prostate patients.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evaluation of VMAT Planning Strategies for Prostate Patients with Bilateral Hip Prosthesis

Xhaferllari

Liu

et al. 2021

Technol Cancer Res Treat

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“…More modern planning techniques such as the fusion of MRI to aid prostate delineation and volumetric modulated arc therapy mean that, in our experience, hypofractionated regimens can usually be delivered to males with even bilateral THJRs, whilst respecting critical structure dose constraints. 28,29 One relatively small single institutional study suggested on post-hoc analysis that males with more obstructive urinary symptoms (international prostate symptom score >12) had worse late urinary toxicity following hypofractionated radiotherapy. 22 These findings have not been replicated in other randomized studies of moderately hypofractionated regimens.…”

Section: Patient Selectionmentioning

confidence: 99%

Moderately hypofractionated prostate external-beam radiotherapy: an emerging standard

Martin

Supiot

Keall

et al. 2018

The British Journal of Radiology

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“…Volumetric modulated arc therapy (VMAT) has been shown to be superior to intensity-modulated radiotherapy therapy (IMRT) in providing better target coverage and increased OAR sparing. [17][18][19] Rana et al showed that using several "skip arcs" (those that avoid going through the prosthesis) for a patient with a bilateral hip prosthesis was superior to traditional IMRT in terms of producing better plan conformity and lower bladder and rectum doses. All published studies investigating the use of VMAT for patients with prostate cancer with hip prosthesis have used skip arcs, and none have addressed the potential of using full VMAT arcs when a robust and accurate treatment planning system is available.…”

Section: Introductionmentioning

confidence: 99%

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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Volumetric modulated arc therapy for prostate cancer patients with hip prosthesis

Cited by 21 publications

References 22 publications

Evaluation of VMAT Planning Strategies for Prostate Patients with Bilateral Hip Prosthesis

Evaluation of VMAT Planning Strategies for Prostate Patients with Bilateral Hip Prosthesis

Moderately hypofractionated prostate external-beam radiotherapy: an emerging standard

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

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