open access

Vol 24, No 6 (2019)
Original research articles
Published online: 2019-11-01
Submitted: 2018-12-24
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Comparison of patient-specific intensity modulated radiation therapy quality assurance for the prostate across multiple institutions

Kazuki Kubo, Hajime Monzen, Kohei Shimomura, Kenji Matsumoto, Tomoharu Sato, Mikoto Tamura, Kiyoshi Nakamatsu, Kentaro Ishii, Ryu Kawamorita
DOI: 10.1016/j.rpor.2019.09.009
·
Rep Pract Oncol Radiother 2019;24(6):600-605.

open access

Vol 24, No 6 (2019)
Original research articles
Published online: 2019-11-01
Submitted: 2018-12-24

Abstract

Aim

To evaluate the success of a patient-specific intensity modulated radiation therapy (IMRT) quality assurance (QA) practice for prostate cancer patients across multiple institutions using a questionnaire survey.

Background

The IMRT QA practice involves different methods of dose distribution verification and analysis at different institutions.

Materials and Methods

Two full-arc volumetric modulated arc therapy (VMAT) plan and 7 fixed-gantry IMRT plan with DMLC were used for patient specific QA across 22 institutions. The same computed tomography image and structure set were used for all plans. Each institution recalculated the dose distribution with fixed monitor units and without any modification. Single-point dose measurement with a cylindrical ionization chamber and dose distribution verification with a multi-detector or radiochromic film were performed, according to the QA process at each institution.

Results

Twenty-two institutions performed the patient-specific IMRT QA verifications. With a single-point dose measurement at the isocenter, the average difference between the calculated and measured doses was 0.5 ± 1.9%. For the comparison of dose distributions, 18 institutions used a two or three-dimensional array detector, while the others used Gafchromic film. In the γ test with dose difference/distance-to-agreement criteria of 3%−3 mm and 2%−2 mm with a 30% dose threshold, the median gamma pass rates were 99.3% (range: 41.7%–100.0%) and 96.4% (range: 29.4%–100.0%), respectively.

Conclusion

This survey was an informative trial to understand the verification status of patient-specific IMRT QA measurements for prostate cancer. In most institutions, the point dose measurement and dose distribution differences met the desired criteria.

Abstract

Aim

To evaluate the success of a patient-specific intensity modulated radiation therapy (IMRT) quality assurance (QA) practice for prostate cancer patients across multiple institutions using a questionnaire survey.

Background

The IMRT QA practice involves different methods of dose distribution verification and analysis at different institutions.

Materials and Methods

Two full-arc volumetric modulated arc therapy (VMAT) plan and 7 fixed-gantry IMRT plan with DMLC were used for patient specific QA across 22 institutions. The same computed tomography image and structure set were used for all plans. Each institution recalculated the dose distribution with fixed monitor units and without any modification. Single-point dose measurement with a cylindrical ionization chamber and dose distribution verification with a multi-detector or radiochromic film were performed, according to the QA process at each institution.

Results

Twenty-two institutions performed the patient-specific IMRT QA verifications. With a single-point dose measurement at the isocenter, the average difference between the calculated and measured doses was 0.5 ± 1.9%. For the comparison of dose distributions, 18 institutions used a two or three-dimensional array detector, while the others used Gafchromic film. In the γ test with dose difference/distance-to-agreement criteria of 3%−3 mm and 2%−2 mm with a 30% dose threshold, the median gamma pass rates were 99.3% (range: 41.7%–100.0%) and 96.4% (range: 29.4%–100.0%), respectively.

Conclusion

This survey was an informative trial to understand the verification status of patient-specific IMRT QA measurements for prostate cancer. In most institutions, the point dose measurement and dose distribution differences met the desired criteria.

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Keywords

Patient-specific IMRT QA; Consistency; VMAT; Survey; Multiple institutions

About this article
Title

Comparison of patient-specific intensity modulated radiation therapy quality assurance for the prostate across multiple institutions

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 24, No 6 (2019)

Pages

600-605

Published online

2019-11-01

DOI

10.1016/j.rpor.2019.09.009

Bibliographic record

Rep Pract Oncol Radiother 2019;24(6):600-605.

Keywords

Patient-specific IMRT QA
Consistency
VMAT
Survey
Multiple institutions

Authors

Kazuki Kubo
Hajime Monzen
Kohei Shimomura
Kenji Matsumoto
Tomoharu Sato
Mikoto Tamura
Kiyoshi Nakamatsu
Kentaro Ishii
Ryu Kawamorita

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