Benchmarking Monte-Carlo dose calculation for MLC CyberKnife treatments.

Mackeprang, Paul-Henry; Vuong, D; Volken, Werner; Henzen, Dominik; Schmidhalter, Daniel; Malthaner, Marco; Müller, Silvan Andreas; Frei, Daniel; Kilby, W; Aebersold, Daniel; Fix, Michael; Manser, Peter (2019). Benchmarking Monte-Carlo dose calculation for MLC CyberKnife treatments. Radiation oncology, 14(1), p. 172. BioMed Central 10.1186/s13014-019-1370-5

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BACKGROUND Vendor-independent Monte Carlo (MC) dose calculation (IDC) for patient-specific quality assurance of multi-leaf collimator (MLC) based CyberKnife treatments is used to benchmark and validate the commercial MC dose calculation engine for MLC based treatments built into the CyberKnife treatment planning system (Precision MC). METHODS The benchmark included dose profiles in water in 15 mm depth and depth dose curves of rectangular MLC shaped fields ranging from 7.6 mm × 7.7 mm to 115.0 mm  × 100.1 mm, which were compared between IDC, Precision MC and measurements in terms of dose difference and distance to agreement. Dose distributions of three phantom cases and seven clinical lung cases were calculated using both IDC and Precision MC. The lung PTVs ranged from 14 cm3 to 93 cm3. Quantitative comparison of these dose distributions was performed using dose-volume parameters and 3D gamma analysis with 2% global dose difference and 1 mm distance criteria and a global 10% dose threshold. Time to calculate dose distributions was recorded and efficiency was assessed. RESULTS Absolute dose profiles in 15 mm depth in water showed agreement between Precision MC and IDC within 3.1% or 1 mm. Depth dose curves agreed within 2.3% / 1 mm. For the phantom and clinical lung cases, mean PTV doses differed from - 1.0 to + 2.3% between IDC and Precision MC and gamma passing rates were > =98.1% for all multiple beam treatment plans. For the lung cases, lung V20 agreed within ±1.5%. Calculation times ranged from 2.2 min (for 39 cm3 PTV at 1.0 × 1.0 × 2.5 mm3 native CT resolution) to 8.1 min (93 cm3 at 1.1 × 1.1 × 1.0 mm3), at 2% uncertainty for Precision MC for the 7 examined lung cases and 4-6 h for IDC, which, however, is not optimized for efficiency but used as a gold standard for accuracy. CONCLUSIONS Both accuracy and efficiency of Precision MC in the context of MLC based planning for the CyberKnife M6 system were benchmarked against MC based IDC framework. Precision MC is used in clinical practice at our institute.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Radiation Oncology > Medical Radiation Physics
04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Radiation Oncology
04 Faculty of Medicine > Department of General Internal Medicine (DAIM) > Clinic of General Internal Medicine

UniBE Contributor:

Mackeprang, Paul-Henry; Volken, Werner; Henzen, Dominik; Schmidhalter, Daniel; Malthaner, Marco; Müller, Silvan Andreas; Frei, Daniel; Aebersold, Daniel; Fix, Michael and Manser, Peter

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1748-717X

Publisher:

BioMed Central

Language:

English

Submitter:

Beatrice Scheidegger

Date Deposited:

27 Sep 2019 12:42

Last Modified:

02 Dec 2019 13:13

Publisher DOI:

10.1186/s13014-019-1370-5

PubMed ID:

31533746

Uncontrolled Keywords:

Benchmarking CyberKnife Dose calculation Monte Carlo QA TPS

BORIS DOI:

10.7892/boris.133501

URI:

https://boris.unibe.ch/id/eprint/133501

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