A comparison of the quality assurance of four dosimetric tools for intensity modulated radiation therapy

  • Jaeman Son Korea University
  • Taesung Baek Ilsan Hospital
  • Boram Lee Sun hospital
  • Dongho Shin National Cancer Center
  • Sungyong Park McLaren Reginonal Medical Center
  • Jeonghoon Park National Cancer Center
  • Youngkyung Lim National Cancer Center
  • Sebyeong Lee National Cancer Center
  • Jooyoung Kim National Cancer Center
  • Myonggeun Yoon Korea University

Abstract

Purpose: This study was designed to compare the quality assurance (QA) results of four dosimetric tools used for intensity modulated radiation therapy (IMRT) and to suggest universal criteria for the passing rate in QA, irrespective of the dosimetric tool used.

Methods and Materials: Thirty fields of IMRT plans from five patients were selected, followed by irradiation onto radiochromic film, a diode array (Mapcheck), an ion chamber array (MatriXX) and an electronic portal imaging device (EPID) for patient-specific QA. The measured doses from the four dosimetric tools were compared with the dose calculated by the treatment planning system. The passing rates of the four dosimetric tools were calculated using the gamma index method, using as criteria a dose difference of 3% and a distance-to-agreement of 3 mm.

Results: The QA results based on Mapcheck, MatriXX and EPID showed good agreement, with average passing rates of 99.61%, 99.04% and 99.29%, respectively. However, the average passing rate based on film measurement was significantly lower, 95.92%. The average uncertainty (1 standard deviation) of passing rates for 6 intensity modulated fields was around 0.31 for film measurement, larger than those of the other three dosimetric tools.

Conclusions: QA results and consistencies depend on the choice of dosimetric tool. Universal passing rates should depend on the normalization or inter-comparisons of dosimetric tools if more than one dosimetric tool is used for patient specific QA.
Published
2015-10-07
How to Cite
Son, J., Baek, T., Lee, B., Shin, D., Park, S., Park, J., Lim, Y., Lee, S., Kim, J., & Yoon, M. (2015). A comparison of the quality assurance of four dosimetric tools for intensity modulated radiation therapy. Radiology and Oncology, 49(3). Retrieved from https://www.radioloncol.com/index.php/ro/article/view/2281
Section
Medical Physics