The online version of this article (10.1186/s13014-017-0936-3) contains supplementary material, which is available to authorized users.
Preclinical radiation biology has become increasingly sophisticated due to the implementation of advanced small animal image guided radiation platforms into laboratory investigation. These small animal radiotherapy devices enable state-of-the-art image guided therapy (IGRT) research to be performed by combining high-resolution cone beam computed tomography (CBCT) imaging with an isocentric irradiation system. Such platforms are capable of replicating modern clinical systems similar to those that integrate a linear accelerator with on-board CBCT image guidance.
In this study, we present a dosimetric evaluation of the small animal radiotherapy research platform (SARRP, Xstrahl Inc.) focusing on small field dosimetry. Physical dosimetry was assessed using ion chamber for calibration and radiochromic film, investigating the impact of beam focus size on the dose rate output as well as beam characteristics (beam shape and penumbra). Two film analysis tools) have been used to assess the dose output using the 0.5 mm diameter aperture.
Good agreement (between 1.7–3%) was found between the measured physical doses and the data provided by Xstrahl for all apertures used. Furthermore, all small field dosimetry data are in good agreement for both film reading methods and with our Monte Carlo simulations for both focal spot sizes. Furthermore, the small focal spot has been shown to produce a more homogenous beam with more stable penumbra over time.
FilmQA Pro is a suitable tool for small field dosimetry, with a sufficiently small sampling area (0.1 mm) to ensure an accurate measurement. The electron beam focus should be chosen with care as this can potentially impact on beam stability and reproducibility.
Additional file 1: Figure S1. Profiles for Dose Deposition for the entire range of therapeutic apertures for broad focus irradiation. Data was obtained using FilmQA Pro for 3 independent exposures for a) 31 cm SSD, b) 34 cm SSD and c) 38 cm SSD. Data is shown as average from 3 independent repeats ± standard error. (PDF 314 kb)
Additional file 2: Figure S2. Beam uniformity profile across the irradiated area for full set of therapeutic apertures. Beam profiles are presented for three different SSD at a depth of 0.15 mm in the phantom. Apertures sizes are: a) 5 × 5 mm, b) 3 × 3 mm, c) 3x9mm along x axis, d) 3x9mm along y axis, e) 1 mm diameter and f) 0.5 mm diameter. (PDF 317 kb)
Additional file 3: Figure S3. Beam uniformity profile across the irradiated area for full set of therapeutic apertures. Beam profiles are presented for three different SSD at a depth of 0.15 mm in the phantom. Apertures sizes are: a) 5 × 5 mm, b) 3 × 3 mm, c) 3x9mm along x axis, d) 3x9mm along y axis, e) 1 mm diameter and f) 0.5 mm diameter. (PDF 326 kb)
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- Small field dosimetry for the small animal radiotherapy research platform (SARRP)
Stephen J. McMahon
Hannah F. Thompson
Conor K. McGarry
Sarah O. S. Osman
Jonathan L. Kane
Karl T. Butterworth
Alan R. Hounsell
Kevin M. Prise
- BioMed Central
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