Abstract
EBT3 film offers high spatial resolution and low energy dependence, making it a suitable choice for quality assurance where high dose gradients are present, such as the case for SBRT. This work presents a simple method to adjust scanner settings so that dose response becomes linear. This linearity eliminates the need to obtain a calibration curve and associated uncertainties in curve fitting. Relative dosimetry can be performed after dose normalization to a reference point. Linearity is also a more robust condition than calibration curve with respect to scanner warm-up conditions, resulting in reduced uncertainty in dose measurement. An in-house developed program reads the film scan and a 2D dose map then constructs both to virtual films using grayscale values. Film intensity value was normalized to dose at reference point. Relative dosimetry was performed by comparing the two resulting images. Patient specific quality assurance was conducted for two SBRT cases. In both plans more than 95% gamma function points passed the gamma criteria of 2%/3mm.
Highlights
Stereotactic body radiation therapy (SBRT) uses high dose radiation to target and destroy a well-defined tumour
Patient specific quality assurance was conducted for two SBRT cases
A typical film dosimetry system requires establishing a calibration curve which converts change in optical density (OD) to absolute dose [4]
Summary
Stereotactic body radiation therapy (SBRT) uses high dose radiation to target and destroy a well-defined tumour In such procedures high dose gradients are often present to spare the surrounding healthy tissues from radiation damage. Patient specific quality assurance (QA) is an important step in making sure the planned dose is deliverable and the desired treatment outcome can be achieved [1,2,3] Radiochromic film dosimeter such as EBT3 film offers high spatial resolution, near tissue equivalence and low energy dependence, making it a suitable choice for SBRT QA. Delivered dose at other points on the film can be normalized and compared with planned dose directly This will greatly simplify the film dosimetry procedure. Another advantage is that as linearity method does not rely on establishing a calibration curve, uncertainties in curve fitting
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
