J Korean Soc Ther Radiol Oncol.  2002 Dec;20(4):391-395.

Radiation Dose Accuracy at the Isocenter: Standard Stereotactic Radiosurgery Technique Developed at Seoul National University Hospital

• Shin SS
• Kim IH
• Ha SW
• Park CI
• Kang WS
• Hur SN

Abstract

PURPOSE: To confirm the accuracy of the radiation dose at the isocenter by the standard linear accelerator-based stereotactic radiosurgery technique which was developed at Seoul National University Hospital.
MATERIALS AND METHODS
Radiation dosimetry was undertaken during standard 5-arc radiosurgery using 6 MV X-ray beam from CL2100C linac. The treatment head was attached with circular tertiary collimators of 10 and 20 mm diameter. We measured the absorbed dose at the isocenter of a multi-purpose phantom using two kinds of detector : a 0.125 cc ionization chamber and a silicon diode detector.
RESULTS
The dose differences at each arc plane between the planned dose and the measured dose at the isocenter raged from -0.73% to -2.69% with the 0.125 cc ion chamber, and from -1.29% to -2.91% with the diode detector during radiosurgery with the tertiary collimator of 20 mm diameter. Those with the 10-mm tertiary collimator ranged from -2.39% to -4.25% with the diode.
CONCLUSION
The dose accuracy at the isocenter was +/-3%. Therefore, further efforts such as modification in processing of the archived image through DICOM3.0 format are required to lessen the dose difference.

Keyword

Stereotactic radiosurgery; Multi-purpose phantom; Isocenter dose

MeSH Terms

Head
Radiometry
Radiosurgery*
Rage
Seoul*
Silicon
Silicon