J Korean Soc Ther Radiol Oncol.  2007 Dec;25(4):249-260.

A Pilot Study for the Remote Monitoring of IMRT Using a Head and Neck Phantom

Affiliations
  • 1Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. youngyih@skku.edu
  • 2Korea Food and Drug Administration (KFDA), Seoul, Korea.
  • 3Department of Radiation Oncology, Kang Dong Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea.
  • 4Department of Radiation Oncology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea.
  • 5Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Korea.
  • 6Proton Therapy Center, National Cancer Center, Ilsan, Korea.

Abstract

PURPOSE: In order to enhance the quality of IMRT as employed in Korea, we developed a remote monitoring system. The feasibility of the system was evaluated by conducting a pilot study.
MATERIALS AND METHODS
The remote monitoring system consisted of a head and neck phantom and a user manual. The phantom contains a target and three OARs (organs at risk) that can be detected on CT images. TLD capsules were inserted at the center of the target and at the OARs. Two film slits for GafchromicEBT film were located on the axial and saggital planes. The user manual contained an IMRT planning guide and instructions for IMRT planning and the delivery process. After the manual and phantom were sent to four institutions, IMRT was planed and delivered. Predicted doses were compared with measured doses. Dose distribution along the two straight lines that intersected at the center of the axial film was measured and compared with the profiles predicted by the plan.
RESULTS
The measurements at the target agreed with the predicted dose within a 3% deviation. Doses at the OARs that represented the thyroid glands showed larger deviations (minimum 3.3% and maximum 19.8%). The deviation at OARs that represented the spiral cord was 0.7~14.8%. The percentage of dose distributions that showed more than a 5% of deviation on the lines was 7~27% and 7~14% along the horizontal and vertical lines, respectively. CONCULSION: Remote monitoring of IMRT using the developed system was feasible. With remote monitoring, the deviation at the target is expected to be small while the deviation at the OARs can be very large. Therefore, a method that is able to investigate the cause of a large deviation needs to be developed. In addition, a more clinically relevant measure for the two-dimensional dose comparison and pass/fail criteria need to be further developed.

Keyword

IMRT; Head and neck phantom; Remote auditing; Quality assurance

MeSH Terms

Capsules
Head*
Korea
Neck*
Pilot Projects*
Thyroid Gland
Capsules
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