open access

Vol 24, No 2 (2019)
Original research articles
Published online: 2019-03-01
Submitted: 2018-04-17
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Dosimetric impact of statistical uncertainty on Monte Carlo dose calculation algorithm in volumetric modulated arc therapy using Monaco TPS for three different clinical cases

Mohandass Palanisamy, Khanna David, Manigandan Durai, Narendra Bhalla, Abhishek Puri
DOI: 10.1016/j.rpor.2019.01.005
·
Rep Pract Oncol Radiother 2019;24(2):188-199.

open access

Vol 24, No 2 (2019)
Original research articles
Published online: 2019-03-01
Submitted: 2018-04-17

Abstract

Aim

To study the dosimetric impact of statistical uncertainty (SU) per plan on Monte Carlo (MC) calculation in Monaco™ treatment planning system (TPS) during volumetric modulated arc therapy (VMAT) for three different clinical cases.

Background

During MC calculation SU is an important factor to decide dose calculation accuracy and calculation time. It is necessary to evaluate optimal acceptance of SU for quality plan with reduced calculation time.

Materials and methods

Three different clinical cases as the lung, larynx, and prostate treated using VMAT technique were chosen. Plans were generated with Monaco™ V5.11 TPS with 2% statistical uncertainty. By keeping all other parameters constant, plans were recalculated by varying SU, 0.5%, 1%, 2%, 3%, 4%, and 5%. For plan evaluation, conformity index (CI), homogeneity index (HI), dose coverage to PTV, organ at risk (OAR) dose, normal tissue receiving dose ≥5Gy and ≥10Gy, integral dose (NTID), calculation time, gamma pass rate, calculation reproducibility and energy dependency were analyzed.

Results

CI and HI improve as SU increases from 0.5% to 5%. No significant dose difference was observed in dose coverage to PTV, OAR doses, normal tissue receiving dose ≥5Gy and ≥10Gy and NTID. Increase of SU showed decrease in calculation time, gamma pass rate and increase in PTV max dose. No dose difference was seen in calculation reproducibility and dependent on energy.

Conclusion

For VMAT plans, SU can be accepted from 1% to 3% per plan with reduced calculation time without compromising plan quality and deliverability by accepting variations in point dose within the target.

Abstract

Aim

To study the dosimetric impact of statistical uncertainty (SU) per plan on Monte Carlo (MC) calculation in Monaco™ treatment planning system (TPS) during volumetric modulated arc therapy (VMAT) for three different clinical cases.

Background

During MC calculation SU is an important factor to decide dose calculation accuracy and calculation time. It is necessary to evaluate optimal acceptance of SU for quality plan with reduced calculation time.

Materials and methods

Three different clinical cases as the lung, larynx, and prostate treated using VMAT technique were chosen. Plans were generated with Monaco™ V5.11 TPS with 2% statistical uncertainty. By keeping all other parameters constant, plans were recalculated by varying SU, 0.5%, 1%, 2%, 3%, 4%, and 5%. For plan evaluation, conformity index (CI), homogeneity index (HI), dose coverage to PTV, organ at risk (OAR) dose, normal tissue receiving dose ≥5Gy and ≥10Gy, integral dose (NTID), calculation time, gamma pass rate, calculation reproducibility and energy dependency were analyzed.

Results

CI and HI improve as SU increases from 0.5% to 5%. No significant dose difference was observed in dose coverage to PTV, OAR doses, normal tissue receiving dose ≥5Gy and ≥10Gy and NTID. Increase of SU showed decrease in calculation time, gamma pass rate and increase in PTV max dose. No dose difference was seen in calculation reproducibility and dependent on energy.

Conclusion

For VMAT plans, SU can be accepted from 1% to 3% per plan with reduced calculation time without compromising plan quality and deliverability by accepting variations in point dose within the target.

Get Citation

Keywords

Statistical uncertainty; Monte Carlo dose algorithm; VMAT; Lung; Larynx; Prostate

About this article
Title

Dosimetric impact of statistical uncertainty on Monte Carlo dose calculation algorithm in volumetric modulated arc therapy using Monaco TPS for three different clinical cases

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 24, No 2 (2019)

Pages

188-199

Published online

2019-03-01

DOI

10.1016/j.rpor.2019.01.005

Bibliographic record

Rep Pract Oncol Radiother 2019;24(2):188-199.

Keywords

Statistical uncertainty
Monte Carlo dose algorithm
VMAT
Lung
Larynx
Prostate

Authors

Mohandass Palanisamy
Khanna David
Manigandan Durai
Narendra Bhalla
Abhishek Puri

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