Program Information
In Vivo Peripheral Dose Measurements in IMRT and CyberKnife Treatments Using Gafchromic EBT3 Films
Ganapathy K1*, Murali V2 , Muthukumaran M3 , Velmurugan J4 , (1) ,,,(2) Apollo Cancer Institutes, Chennai, Tamil Nadu, (3) ,,,(4) Anna University, Chennai, Tamilnadu
Presentations
SU-I-GPD-T-308 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: The objective of this study is to check whether Gafchromic EBT3 films can be used to measure the dose delivered to peripheral sites in patients treated with IMRT and CyberKnife techniques
Methods: Peripheral dose measurements were done for patients with intracranial lesions undergoing IMRT or CyberKnife treatments in this study. Measurements were carried out on 15 patients treated with IMRT and on 15 patients treated with CyberKnife technique. The age group of the patients ranged from 16 years to 62 years. Gafchromic EBT3 films were used along with the TLD dosimeters tomeasure the dose delivered to peripheral sites. The dose was measured at skin level on chin, neck, upper chest, middle chest and upper diaphragm to represent the dose delivered to Mandible, Thyroid, Lung epics, Heart and the upper diaphragm. The dose measured using the EBT3 film was then compared with the dose measured using the TLD.
Results: In IMRT patients, the maximum difference between peripheral dose measured using EBT3 film and TLD was 5.3 cGy,4.2 cGy,2.6 cGy,3.2 cGy and 1.5 cGy at chin, neck, upper chest, middle chest and upper diaphragm respectively. In CyberKnife patients, the maximum difference between peripheral dose measured using EBT3 film and TLD was 3.1 cGy, 3.5 cGy, 2.5 cGy, 1.4 cGy and 1.2 cGy at chin, neck, upper chest, middle chest and upper diaphragm respectively.
Conclusion: The dose measured using EBT3 film pieces have agreed closely with the dose measured using the LiF TLD in IMRT as well as CyberKnife treatments. Gafchromic EBT3 films are able to record the small dose delivered to sensitive regions away from the treatment site. Considering the ease in implementation of the film dosimetry, EBT3 film is an ideal alternative to TLDs in peripheral dose measurements.
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