ICMP 2103, Brighton, United Kingdom, 1 - 04 September 2013, vol.1, no.2, pp.568
The contribution of in-vivo dose measurement of organs at risk by TLD-LiF100 and IDF-thin IBA diode during IMRT in treatment of nasopharyngeal cancer was studied.
IMRT planning were fusion on CT images of rando phantom. For PTVI-II-III the equally angel ninefields IMRT plans were designed using 6MV energy with 200cGy/fr to 50, 60 and 70Gy respectively. The dose measurements for the quality control evaluation of IMRT plans were done. Nasal-cavity location was selected for PTVs. The selected locations for parotid and thyroid were oral-cavity and ear-cavity, and on the skin. Each dosimeter was selected and located on measurement region. In-vivo dose measurements were performed and repeated, the dose for PTV and OARs compared with TPS.
The percentage dose differences between TPS and TLD for nasal-cavity location where represented higher by diode that may be reduced by using suitable fixation. By diode the %dose differences in the ear and oral cavity that recommended locations for parotid were %1.7 and %8.7 in phase-I, %1.5 and %6.7 in phase-II respectively. The calculated and measured dose of thyroid in phase-II (5.8cGy) and phase-III (2cGy) was compatible. In phase-I dose difference were obtained 39%.
QA of IMRT nasopharyngeal cancer patients dose by in-vivo dosimetry was determined as an ideal and reliable dose control method in terms of PTV and OARs by TLD or diode.