Accuracy of dose‐volume metric calculation for small‐volume radiosurgery targets

Stanley, Dennis N.; Covington, Elizabeth; Liu, Haisong; Alexandrian, A; Cardan, R; Bridges, Daniel S.; Thomas, Evan M.; Fiveash, John B.; Popple, Richard A.

doi:10.1002/mp.14645

Cited by 10 publications

(18 citation statements)

References 28 publications

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“…Increasing the resolution in the DVH binning might be advisable for the vendor to achieve in order to maintain lower volumetric and dosimetric uncertainties, especially for small SBRT/SRS target plans. 23 The performance of the image use and display tests was in line with previously published TPS commissioning studies for other treatment planning systems. 24,25…”

Section: Non-dosimetric Testssupporting

confidence: 78%

“…Eclipse bins the DVH using 0.1 cGy resolution whereas RefleXion X1 uses lower resolution depending on maximum dose in the plan: 10 cGy resolution for 1000–5000 cGy D max and 20 cGy resolution for 6000–9000 cGy D max . Increasing the resolution in the DVH binning might be advisable for the vendor to achieve in order to maintain lower volumetric and dosimetric uncertainties, especially for small SBRT/SRS target plans 23 …”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Treatment planning system commissioning of the first clinical biology‐guided radiotherapy machine

Simiele

Capaldi

Breitkreutz

et al. 2022

J Applied Clin Med Phys

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Purpose The RefleXion X1 is a novel radiotherapy machine designed for image‐guided radiotherapy (IGRT) and biology‐guided radiotherapy (BgRT). Its treatment planning system (TPS) generates IMRT and SBRT plans for a 6MV‐FFF beam delivered axially via 50 firing positions with the couch advancing every 2.1 mm. The purpose of this work is to report the TPS commissioning results for the first clinical installation of RefleXion™ X1. Methods CT images of multiple phantoms were imported into the RefleXion TPS to evaluate the accuracy of data transfer, anatomical modeling, plan evaluation, and dose calculation. Comparisons were made between the X1, Eclipse™, and MIM™. Dosimetric parameters for open static fields were evaluated in water and heterogeneous slab phantoms. Representative clinical IMRT and SBRT cases were planned and verified with ion chamber, film, and ArcCHECK@ measurements. The agreement between TPS and measurements for various clinical plans was evaluated using Gamma analysis with a criterion of 3%/2 mm for ArcCHECK@ and film. End‐to‐end (E2E) testing was performed using anthropomorphic head and lung phantoms. Results The average difference between the TPS‐reported and known HU values was −1.4 ± 6.0 HU. For static fields, the agreements between the TPS‐calculated and measured PDD10, crossline profiles, and inline profiles (FWHM) were within 1.5%, 1.3%, and 0.5 mm, respectively. Measured output factors agreed with the TPS within 1.3%. Measured and calculated dose for static fields in heterogeneous phantoms agreed within 2.5%. The ArcCHECK@ mean absolute Gamma passing rate was 96.4% ± 3.4% for TG 119 and TG 244 plans and 97.8% ± 3.6% for the 21 clinical plans. E2E film analysis showed 0.8 mm total targeting error for isocentric and 1.1 mm for off‐axis treatments. Conclusions The TPS commissioning results of the RefleXion X1 TPS were within the tolerances specified by AAPM TG 53, MPPG 5.a, TG 119, and TG 148. A subset of the commissioning tests has been identified as baseline data for an ongoing QA program.

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Section: Non-dosimetric Testssupporting

confidence: 78%

Section: Discussionmentioning

confidence: 99%

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Treatment planning system commissioning of the first clinical biology‐guided radiotherapy machine

Simiele

Capaldi

Breitkreutz

et al. 2022

J Applied Clin Med Phys

View full text Add to dashboard Cite

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“…Comparing to a ground truth motivated Nelms et al 14 to develop synthetic inputs for which the true DVH could be analytically derived, a technique that was later also adapted for radiosurgery planning. 15 DVH variability was also evident in our clinics when comparing between third-party calculation software, for example, comparing the primary planning system to a system used for an independent second check. Figure 1 shows the variability when calculating DVHs for two representative anatomical structures using five different commercial systems in our clinic.…”

Section: Introductionmentioning

confidence: 78%

“… 14 and Stanley et al. 15 and the precision metric described here c . This would help reduce the variability between vendors and decrease one more source of uncertainty in the radiotherapy treatment process.…”

Section: Discussionmentioning

confidence: 96%

Assessment of dose‐volume histogram precision for five clinical systems

et al. 2022

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To investigate the dependency of dose-volume histogram (DVH) behavior and precision on underlying discretization using shapes and dose distributions with known analytical DVHs for five commercial DVH calculators. Methods: DVHs and summary metrics were extracted from all five systems using synthetic cone and cylinder objects for which the true volume and DVH curves were known. Trends in the curves and metrics were explored by varying the underlying voxelization of the CT image, structure set, and dose grid as well by varying the geometry of the structure and direction of a linear dose gradient. Using synthetic structures allowed for comparison with ground truth DVH curves to assess their accuracy while an algorithm was additionally developed to assess the precision of each system. The precision was calculated with a novel algorithm that treats any "stair step" behavior in a DVH curve as an uncertainty band and calculates the width, characterized as a percent difference, of the band for various DVH metrics. The underlying voxelization was additionally changed and DVHs were extracted for two clinical examples. The details of how each system calculated DVHs were also investigated and tendencies in the calculated curves, metrics, and precision were related to choices made in the calculation methodology. Results: Calculation methodology differences that had a noticeable impact on the DVH curves and summary metrics include supersampling beyond the input grids and interpretation of the superior and inferior ends of the structures. Among the systems studied, the median precision ranged from 0.902% to 3.22%, and interquartile ranges varied from 1.09% to 3.91%. Conclusions: Commercial dose-evaluation solutions can calculate different DVH curves, structure volume measures, and dose statistics for the same input data due to differences in their calculation methodologies. This study highlights the importance of understanding and investigating the DVH calculation when considering a new clinical system and when using more than one system for data transfer. K E Y W O R D S dose-volume histogram, DVH analysis, treatment planning systems

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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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Accuracy of dose‐volume metric calculation for small‐volume radiosurgery targets

Cited by 10 publications

References 28 publications

Treatment planning system commissioning of the first clinical biology‐guided radiotherapy machine

Treatment planning system commissioning of the first clinical biology‐guided radiotherapy machine

Assessment of dose‐volume histogram precision for five clinical systems

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

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