Assessment of dose‐volume histogram precision for five clinical systems

Pepin, M.; Brom, Kevin M.; Gustafson, Jon M.; Long, Kenneth M.; Santos, Luis E. Fong de los; Shiraishi, S.; Penoncello, Gregory P.; Rong, Yi

doi:10.1002/mp.15916

Cited by 5 publications

(3 citation statements)

References 22 publications

(52 reference statements)

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“…Apart from the difference between dose calculation algorithms, volume calculation is handled differently in different TPSs. 19 , 22 , 23 , 24 , 25 The volumes from the same DICOM structure set are reported differently because each TPS has its own algorithm to model 3D volumes, such as shape‐based interpolation and linear interpolation. DVH is calculated by binning the dose values inside the volume of specific structure through a sampling technique.…”

Section: Discussionmentioning

confidence: 99%

The dosimetric impact of titanium implants in spinal SBRT using four commercial treatment planning algorithms

Liu

Cho

Magnelli

et al. 2023

J Applied Clin Med Phys

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To evaluate the dosimetric impact of titanium implants in spine SBRT using four dose calculation algorithms. Twenty patients with titanium implants in the spine treated with SBRT without density override (DO) were selected. The clinical plan for each patient was created in Pinnacle and subsequently imported into Eclipse (AAA and AcurosXB) and Raystation (CC) for dose evaluation with and without DO to the titanium implant. We renormalized all plans such that 90% of the tumor volume received the prescription dose and subsequently evaluated the following dose metrics: (1) the maximum dose to 0.03 cc (Dmax), dose to 99% (D99%) and 90% (D90%) of the tumor volume; (2) Dmax and volumetric metrics of the spinal cord. For the same algorithm, plans with and without DO had similar dose distributions. Differences in Dmax, D99% and D90% of the tumor were on average <2% with slightly larger variations up to 5.58% in Dmax using AcurosXB. Dmax of the spinal cord for plans calculated with DO increased but the differences were clinically insignificant for all algorithms (mean: 0.36% ± 0.7%). Comparing to the clinical plans, the relative differences for all algorithms had an average of 1.73% (−10.36%–13.21%) for the tumor metrics and −0.93% (−9.87%–10.95%) for Dmax of the spinal cord. A few cases with small tumor and spinal cord volumes, dose differences of >10% in both D99% and Dmax of the tumor, and Dmax of the spinal cord were observed. For all algorithms, the presence of titanium implants in the spine for most patients had minimal impact on dose distributions with and without DO. For the same plan calculated with different algorithms, larger differences in volumetric metrics of >10% could be observed, impacted by dose gradient at the plan normalization volume, tumor volumes, plan complexity, and partial voxel volume interpolation.

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Section: Discussionmentioning

confidence: 99%

The dosimetric impact of titanium implants in spinal SBRT using four commercial treatment planning algorithms

Liu

Cho

Magnelli

et al. 2023

J Applied Clin Med Phys

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“…There are inherent statistical uncertainties in the calculation of DVHs which are associated with the underlying discretization of structure contours. Pepin et al 13 . addressed and assessed these uncertainties for several planning systems, including Eclipse, in their research.…”

Section: Methodsmentioning

confidence: 99%

“…There are inherent statistical uncertainties in the calculation of DVHs which are associated with the underlying discretization of structure contours. Pepin et al 13 addressed and assessed these uncertainties for several planning systems, including Eclipse, in their research. However, in this study where the dosimetric parameters for the same plan and similar structures between reference and rotated data were compared, it was decided not to include the inherent uncertainty present in the Eclipse DVH calculation.…”

Section: Phantom Studymentioning

confidence: 99%

Dosimetric effects of rotational errors for single isocenter multiple targets in HyperArc plans: A phantom and retrospective imaging analysis study

Golmakani,

McGrath,

Williams

2023

J Applied Clin Med Phys

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PurposeThis study uses a phantom to investigate the dosimetric impact of rotational setup errors for Single Isocenter Multiple Targets (SIMT) HyperArc plans. Additionally, it evaluates intra‐fractional rotational setup errors in patients treated with Encompass immobilization system.MethodsThe Varian HyperArc system (Varian Medical systems) was used to create plans targeting spherical PTVs with diameters of 5, 10, and 15 mm and with offsets of 1.3–5.3 cm from the isocenter. Dosimetric parameters, including mean and maximum dose, D99% and D95% were evaluated for various rotational setup errors ranging from 0.5° to 2° for the PTVs and certain CTVs created within PTVs. These rotational errors were applied in an order and direction that resulted in the maximum displacement of targets. The rotation was applied both uniformly around all three axes and individually around each axis. Furthermore, to link the findings to actual treatment scenarios, the intra‐fractional rotational setup errors were obtained for stereotactic cranial patients treated with the Encompass system using CBCT images acquired during treatments.ResultsThe maximum displacement of 2.7 mm was observed for targets located at 4.4 and 4.5 cm from the isocenter with rotational setup errors of 2°. The dose reduction for D99% values corresponding to this displacement were about 50%, 40%, and 30% for PTVs with diameters of 5, 10, and 15 mm, respectively. Both D99% and D95% showed a consistent trend of dose reduction across various rotational errors and PTV volumes. While the maximum dose remained consistent for different targets with various rotational errors, the mean dose decreased by approximately 25%, 12%, and 6% for PTVs with diameters of 5, 10, and 15 cm, respectively, with rotational errors of 2°. In addition, by analyzing CBCT images, the absolute mean rotational setup errors obtained during treatment with Encompass for pitch, roll, and yaw were 0.17° ± 0.13°, 0.11° ± 0.10°, and 0.12° ± 0.10° respectively. This data, combined with existing studies, suggest that a 0.5° rotational setup error is a safe choice to consider for calculating additional PTV margin to ensure adequate CTV coverage.Therefore, the assessment of maximum displacement and dosimetric parameters in this study, for a 0.5° rotational error, highlights the need for an additional 0.7 mm PTV margin for targets positioned at distances of 4.4 cm or greater from the isocenter.ConclusionsFor SIMT Plans, a 0.5° rotational setup error is recommended as a basis for calculating additional PTV margins to ensure adequate CTV coverage when using the Encompass system.

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Pharyngeal Constrictor Dose–Volume Histogram Metrics and Patient-Reported Dysphagia in Head and Neck Radiotherapy

Paetkau,

Weppler,

Kwok

et al. 2024

Clinical Oncology

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Assessment of dose‐volume histogram precision for five clinical systems

Cited by 5 publications

References 22 publications

The dosimetric impact of titanium implants in spinal SBRT using four commercial treatment planning algorithms

The dosimetric impact of titanium implants in spinal SBRT using four commercial treatment planning algorithms

Dosimetric effects of rotational errors for single isocenter multiple targets in HyperArc plans: A phantom and retrospective imaging analysis study

Pharyngeal Constrictor Dose–Volume Histogram Metrics and Patient-Reported Dysphagia in Head and Neck Radiotherapy

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