Add like
Add dislike
Add to saved papers

SU-E-T-265: Development of Dose-To-Water Conversion Models for Pre-Treatment Verification with the New AS1200 Imager.

Medical Physics 2015 June
PURPOSE: To develop and evaluate models for dose verification of flattened (FF) and flattening filter free (FFF) beams for the new Varian aS1200 backscatter-shielded electronic portal imaging device (EPID).

METHODS: The model converts EPID images to incident energy fluence using deconvolution of EPID scatter kernels and fluence to dose in water using convolution with dose-to-water kernels. Model parameters were optimized using non-transmission EPID images of varying jaw defined field sizes for energies of 6 and 10 MV FF and FFF beams. Energy fluence was obtained from the Acuros planning system and reference dose profiles and output factors were measured at depths of 5, 10, 15 and 20 cm in a water phantom. Images for 34 IMRT fields acquired at 6 and 10 MV FF energy were converted to dose at 10 cm depth in water and compared to treatment planning system dose plane calculations using gamma criteria.

RESULTS: Gamma evaluations for the IMRT fields had mean (1 standard deviation) pass rates of 99.4% (0.8%) and mean gamma scores of 0.32 (0.06) with 2%, 2 mm criteria and 10% of maximum dose threshold.

CONCLUSION: The developed model has been shown to be highly accurate for pre-treatment verification with the new aS1200 imager which does not display support-arm backscatter artefact and has improved dosimetric properties. Further investigation of FFF modes is in progress. The model is currently being evaluated at sites for potential clinical release.

Full text links

We have located links that may give you full text access.
Can't access the paper?
Try logging in through your university/institutional subscription. For a smoother one-click institutional access experience, please use our mobile app.

For the best experience, use the Read mobile app

Mobile app image

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app

All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

By using this service, you agree to our terms of use and privacy policy.

Your Privacy Choices Toggle icon

You can now claim free CME credits for this literature searchClaim now

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app