J Korean Soc Ther Radiol Oncol.  2004 Mar;22(1):64-68.

Feasibility Study of the Real-Time IMRT Dosimetry Using a Scintillation Screen

• Lim SW
• Yi BY
• Ko YE
• Ji YH
• Kim JH
• Ahn SD
• Lee SW
• Shin SS
• Kwon SI
• Choi EK

Abstract

PURPOSE: To study the feasibility of verifying real-time 2-D dose distribution measurement system with the scintillation screen for the quality assurance.
MATERIALS AND METHODS
The water phantom consisted of a scintillation screen (LANEX fast screen, Kodak, USA) that was axially located in the middle of an acrylic cylinder with a diameter of 25 cm. The charge-coupled device (CCD) camera was attached to the phantom in order to capture the visible light from the scintillation screen. To observe the dose distribution in real time, the intensity of the light from the scintillator was converted to a dosage. The isodose contours of the calculations from RTP and those of the measurements using the scintillation screen were compared for the arc therapy and the intensity modulated radiation therapy (IMRT).
RESULTS
The kernel, expressed as a multiplication of two error functions, was obtained in order to correct the sensitivity of the CCD of the camera and the scintillation screen. When comparing the calculated isodose and measured isodose, a discrepancy of less than 8 mm in the high dose region was observed.
CONCLUSIONS
Using the 2-D dosimetry system, the relationship between the light and the dosage could be found, and real-time verification of the dose distribution was feasible.

Keyword

IMRT (intensity modulated radiation therapy); QA (quality assurance); Scintillation screen; Real time dosimetry

MeSH Terms

Feasibility Studies*
Light
Water
Water