| ORIGINAL ARTICLE |
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| Year : 2016 | Volume
: 41
| Issue : 3 | Page : 177-181 |
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Measurement of eye lens dose for Varian On-Board Imaging with different cone-beam computed tomography acquisition techniques
Sudesh Deshpande1, Deepak Dhote2, Kalpna Thakur3, Amol Pawar3, Rajesh Kumar4, Munish Kumar4, MS Kulkarni4, SD Sharma4, V Kannan1
1 Department of Radiation Oncology, P. D. Hinduja National Hospital and MRC, Mumbai, Maharashtra, India
2 Department of Electronics, Brijlal Biyani College, Amravati, Maharashtra, India
3 Department of Radiation Oncology, Holy Spirit Hospital, Mumbai, Maharashtra, India
4 Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
Correspondence Address:
Sudesh Deshpande
Department of Radiation Oncology, P. D. Hinduja National Hospital and MRC, Mumbai, Maharashtra
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0971-6203.189481
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The objective of this work was to measure patient eye lens dose for different cone-beam computed tomography (CBCT) acquisition protocols of Varian's On-Board Imaging (OBI) system using optically stimulated luminescence dosimeter (OSLD) and to study the variation in eye lens dose with patient geometry and distance of isocenter to the eye lens. During the experimental measurements, OSLD was placed on the patient between the eyebrows of both eyes in line of nose during CBCT image acquisition to measure eye lens doses. The eye lens dose measurements were carried out for three different cone-beam acquisition protocols (standard dose head, low-dose head [LDH], and high-quality head [HQH]) of Varian OBI. Measured doses were correlated with patient geometry and distance between isocenter and eye lens. Measured eye lens doses for standard head and HQH protocols were in the range of 1.8-3.2 mGy and 4.5-9.9 mGy, respectively. However, the measured eye lens dose for the LDH protocol was in the range of 0.3-0.7 mGy. The measured data indicate that eye lens dose to patient depends on the selected imaging protocol. It was also observed that eye lens dose does not depend on patient geometry but strongly depends on distance between eye lens and treatment field isocenter. However, undoubted advantages of imaging system should not be counterbalanced by inappropriate selection of imaging protocol, especially for very intense imaging protocol. |
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