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Title: SU-F-J-186: Enabling Adaptive IMPT with CBCT-Based Dose Recalculation for H&N and Prostate Cancer Patients

Abstract

Purpose: To enable adaptive intensity modulated proton therapy for sites sensitive to inter-fractional changes on the basis of accurate CBCT-based proton dose calculations. To this aim two CBCT intensity correction methods are considered: planning CT (pCT) to CBCT DIR and projection correction based on pCT DIR prior. Methods: 3 H&N and 3 prostate cancer patients with CBCT images and corresponding projections were used in this study, in addition to pCT and re-planning CT (rpCT) images (H&N only). A virtual CT (vCT) was generated by pCT to CBCT DIR. In a second approach, the vCT was used as prior for scatter correction of the CBCT projections to yield a CBCTcor image. BEV 2D range maps of SFUD IMPT plans were compared. For the prostate cases, the geometric accuracy of the vCT was also evaluated by contour comparison to physician delineation of the CBCTcor and original CBCT. Results: SFUD dose calculations on vCT and CBCTcor were found to be within 3mm for 97% to 99% of 2D range maps. Median range differences compared to rpCT were below 0.5mm. Analysis showed that the DIR-based vCT approach exhibits inaccuracies in the pelvic region due to the very low soft-tissue contrast in the CBCT. Themore » CBCTcor approach yielded results closer to the original CBCT in terms of DICE coefficients than the vCT (median 0.91 vs 0.81) for targets and OARs. In general, the CBCTcor approach was less affected by inaccuracies of the DIR used during the generation of the vCT prior. Conclusion: Both techniques yield 3D CBCT images with intensities equivalent to diagnostic CT and appear suitable for IMPT dose calculation for most sites. For H&N cases, no considerable differences between the two techniques were found, while improved results of the CBCTcor were observed for pelvic cases due to the reduced sensitivity to registration inaccuracies. Deutsche Forschungsgemeinschaft (MAP); Bundesministerium fur Bildung und Forschung (01IB13001)« less

Authors:
 [1];  [2]; ; ;  [3]; ; ; ; ; ;  [4];  [5];  [6]; ;  [1]
  1. Ludwig-Maximilians-Universitaet Muenchen, Garching b. Muenchen (Germany)
  2. (Germany)
  3. Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)
  4. LMU Munich, Munich (Germany)
  5. University Lyon, Lyon (France)
  6. Aarhus University Hospital, Aarhus (Denmark)
Publication Date:
OSTI Identifier:
22634782
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; ACCURACY; COMPUTERIZED TOMOGRAPHY; CORRECTIONS; IMAGES; NEOPLASMS; PATIENTS; PLANNING; PROSTATE; PROTON BEAMS; RADIATION DOSES; RADIOTHERAPY; SENSITIVITY

Citation Formats

Kurz, C, LMU Munich, Munich, Park, Y, Winey, B, Sharp, G, Kamp, F, Reiner, M, Nijhuis, R, Ganswindt, U, Thieke, C, Belka, C, Rit, S, Hansen, D, Parodi, K, and Landry, G. SU-F-J-186: Enabling Adaptive IMPT with CBCT-Based Dose Recalculation for H&N and Prostate Cancer Patients. United States: N. p., 2016. Web. doi:10.1118/1.4956094.
Kurz, C, LMU Munich, Munich, Park, Y, Winey, B, Sharp, G, Kamp, F, Reiner, M, Nijhuis, R, Ganswindt, U, Thieke, C, Belka, C, Rit, S, Hansen, D, Parodi, K, & Landry, G. SU-F-J-186: Enabling Adaptive IMPT with CBCT-Based Dose Recalculation for H&N and Prostate Cancer Patients. United States. doi:10.1118/1.4956094.
Kurz, C, LMU Munich, Munich, Park, Y, Winey, B, Sharp, G, Kamp, F, Reiner, M, Nijhuis, R, Ganswindt, U, Thieke, C, Belka, C, Rit, S, Hansen, D, Parodi, K, and Landry, G. Wed . "SU-F-J-186: Enabling Adaptive IMPT with CBCT-Based Dose Recalculation for H&N and Prostate Cancer Patients". United States. doi:10.1118/1.4956094.
@article{osti_22634782,
title = {SU-F-J-186: Enabling Adaptive IMPT with CBCT-Based Dose Recalculation for H&N and Prostate Cancer Patients},
author = {Kurz, C and LMU Munich, Munich and Park, Y and Winey, B and Sharp, G and Kamp, F and Reiner, M and Nijhuis, R and Ganswindt, U and Thieke, C and Belka, C and Rit, S and Hansen, D and Parodi, K and Landry, G},
abstractNote = {Purpose: To enable adaptive intensity modulated proton therapy for sites sensitive to inter-fractional changes on the basis of accurate CBCT-based proton dose calculations. To this aim two CBCT intensity correction methods are considered: planning CT (pCT) to CBCT DIR and projection correction based on pCT DIR prior. Methods: 3 H&N and 3 prostate cancer patients with CBCT images and corresponding projections were used in this study, in addition to pCT and re-planning CT (rpCT) images (H&N only). A virtual CT (vCT) was generated by pCT to CBCT DIR. In a second approach, the vCT was used as prior for scatter correction of the CBCT projections to yield a CBCTcor image. BEV 2D range maps of SFUD IMPT plans were compared. For the prostate cases, the geometric accuracy of the vCT was also evaluated by contour comparison to physician delineation of the CBCTcor and original CBCT. Results: SFUD dose calculations on vCT and CBCTcor were found to be within 3mm for 97% to 99% of 2D range maps. Median range differences compared to rpCT were below 0.5mm. Analysis showed that the DIR-based vCT approach exhibits inaccuracies in the pelvic region due to the very low soft-tissue contrast in the CBCT. The CBCTcor approach yielded results closer to the original CBCT in terms of DICE coefficients than the vCT (median 0.91 vs 0.81) for targets and OARs. In general, the CBCTcor approach was less affected by inaccuracies of the DIR used during the generation of the vCT prior. Conclusion: Both techniques yield 3D CBCT images with intensities equivalent to diagnostic CT and appear suitable for IMPT dose calculation for most sites. For H&N cases, no considerable differences between the two techniques were found, while improved results of the CBCTcor were observed for pelvic cases due to the reduced sensitivity to registration inaccuracies. Deutsche Forschungsgemeinschaft (MAP); Bundesministerium fur Bildung und Forschung (01IB13001)},
doi = {10.1118/1.4956094},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}