Polymer gel dosimeters for pretreatment radiotherapy verification using the three-dimensional gamma evaluation and pass rate maps

Ling-Ling Hsieh; Jiunn-I Shieh; Li-Ju Wei; Yi-Chun Wang; Kai-Yuan Cheng; Cheng-Ting Shih

doi:10.1016/j.ejmp.2017.04.018

Polymer gel dosimeters for pretreatment radiotherapy verification using the three-dimensional gamma evaluation and pass rate maps

Phys Med. 2017 May:37:75-81. doi: 10.1016/j.ejmp.2017.04.018. Epub 2017 Apr 24.

Authors

Ling-Ling Hsieh¹, Jiunn-I Shieh², Li-Ju Wei³, Yi-Chun Wang⁴, Kai-Yuan Cheng⁵, Cheng-Ting Shih⁶

Affiliations

¹ Department of Medical Imaging and Radiological Sciences, Central Taiwan University of Science and Technology, No. 666, Buzih Road, Taichung 40601, Taiwan, ROC; Graduate Institute of Biotechnology and Biomedical Engineering, Central Taiwan University of Science and Technology, No. 666, Buzih Road, Taichung 40601, Taiwan, ROC.
² Department of M-Commerce and Multimedia Applications, Asia University, No. 500, Lioufeng Road, Taichung 41354, Taiwan, ROC.
³ 3D Printing Medical Research Center, China Medical University Hospital, China Medical University, No. 2, Yuh-Der Road, Taichung 40447, Taiwan, ROC.
⁴ Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei 11221, Taiwan, ROC; Department of Radiology, China Medical University Hospital, China Medical University, No. 2, Yuh-Der Road, Taichung 40447, Taiwan, ROC.
⁵ Department of Medical Imaging and Radiological Sciences, Central Taiwan University of Science and Technology, No. 666, Buzih Road, Taichung 40601, Taiwan, ROC.
⁶ 3D Printing Medical Research Center, China Medical University Hospital, China Medical University, No. 2, Yuh-Der Road, Taichung 40447, Taiwan, ROC. Electronic address: songofdeath2121@gmail.com.

PMID: 28535918
DOI: 10.1016/j.ejmp.2017.04.018

Abstract

Polymer gel dosimeters (PGDs) have been widely studied for use in the pretreatment verification of clinical radiation therapy. However, the readability of PGDs in three-dimensional (3D) dosimetry remain unclear. In this study, the pretreatment verifications of clinical radiation therapy were performed using an N-isopropyl-acrylamide (NIPAM) PGD, and the results were used to evaluate the performance of the NIPAM PGD on 3D dose measurement. A gel phantom was used to measure the dose distribution of a clinical case of intensity-modulated radiation therapy. Magnetic resonance imaging scans were performed for dose readouts. The measured dose volumes were compared with the planned dose volume. The relative volume histograms showed that relative volumes with a negative percent dose difference decreased as time elapsed. Furthermore, the histograms revealed few changes after 24h postirradiation. For the 3%/3mm and 2%/2mm criteria, the pass rates of the 12- and 24-h dose volumes were higher than 95%, respectively. This study thus concludes that the pass rate map can be used to evaluate the dose-temporal readability of PGDs and that the NIPAM PGD can be used for clinical pretreatment verifications.

Keywords: Dose-temporal readability; Pass rate map; Polymer gel dosimeter; Relative volume histogram; Three-dimensional dosimetry.

MeSH terms

Gels
Humans
Magnetic Resonance Imaging
Phantoms, Imaging
Polymers
Radiation Dosimeters*
Radiometry / instrumentation*
Radiotherapy Dosage*
Radiotherapy Planning, Computer-Assisted

Substances

Gels
Polymers