open access

Vol 23, No 5 (2018)
Original research articles
Published online: 2018-09-01
Submitted: 2017-08-23
Get Citation

EPID-based daily verification of reproducibility of patients’ irradiation with IMRT plans

Marta Kruszyna-Mochalska
DOI: 10.1016/j.rpor.2018.05.003
·
Rep Pract Oncol Radiother 2018;23(5):309-314.

open access

Vol 23, No 5 (2018)
Original research articles
Published online: 2018-09-01
Submitted: 2017-08-23

Abstract

Aim

The aim of the work was to catch potential errors with daily EPID measurements of repeatability of the dose distribution during irradiation of IMRT patients.

Materials and methods

In the first stage, measurements were made using an anthropomorphic phantom in which the method of collecting data with an EPID device and the possibility of detecting errors in positioning were developed. Next, for 23 patients, the pelvis (P) and head and neck (H&N) regions, images were collected with an EPID device for each IMRT subfield daily and compared to reference images using the gamma method (DTA 3mm, DD 3%). Finally, the dependencies between treatment plan parameters, pre-verification results and repeatability of collected images were evaluated.

Results

The anthropomorphic phantom study has shown what kind of effects we can expect with EPID measured at potential shifts during radiotherapy. For the clinical case, score results were obtained for individual tumor regions as below: (P) 0.786±1.046, (H&N) 0.720±1.552. For most evaluated cases, score values were below 1%: (P) 75.5% and (H&N) 83.9% of analyzed fields. 95% of all evaluated data was with the score below: (P) 2.86% and (H&N) 3.40%. The relationship between the results of the analysis of daily collected images and the results of pre-verification, field size and irradiation time was shown.

Conclusions

The EPID-based daily verification can provide extra information about day-to-day repeatability of treatment, without additional dose.

Abstract

Aim

The aim of the work was to catch potential errors with daily EPID measurements of repeatability of the dose distribution during irradiation of IMRT patients.

Materials and methods

In the first stage, measurements were made using an anthropomorphic phantom in which the method of collecting data with an EPID device and the possibility of detecting errors in positioning were developed. Next, for 23 patients, the pelvis (P) and head and neck (H&N) regions, images were collected with an EPID device for each IMRT subfield daily and compared to reference images using the gamma method (DTA 3mm, DD 3%). Finally, the dependencies between treatment plan parameters, pre-verification results and repeatability of collected images were evaluated.

Results

The anthropomorphic phantom study has shown what kind of effects we can expect with EPID measured at potential shifts during radiotherapy. For the clinical case, score results were obtained for individual tumor regions as below: (P) 0.786±1.046, (H&N) 0.720±1.552. For most evaluated cases, score values were below 1%: (P) 75.5% and (H&N) 83.9% of analyzed fields. 95% of all evaluated data was with the score below: (P) 2.86% and (H&N) 3.40%. The relationship between the results of the analysis of daily collected images and the results of pre-verification, field size and irradiation time was shown.

Conclusions

The EPID-based daily verification can provide extra information about day-to-day repeatability of treatment, without additional dose.

Get Citation

Keywords

EPID; Fluency map; Treatment repeatability; IMRT

About this article
Title

EPID-based daily verification of reproducibility of patients’ irradiation with IMRT plans

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 23, No 5 (2018)

Pages

309-314

Published online

2018-09-01

DOI

10.1016/j.rpor.2018.05.003

Bibliographic record

Rep Pract Oncol Radiother 2018;23(5):309-314.

Keywords

EPID
Fluency map
Treatment repeatability
IMRT

Authors

Marta Kruszyna-Mochalska

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