Page 216 - 2014 Printable Abstract Book
P. 216
demonstrate pristine Bragg peaks at depths in water of 23 mm (50 MeV) and 8 mm (30 MeV) with an
output of 10 Gy/min. Monte Carlo simulations predict a high-LET (>10 keV/μm) at the distal end of the
Bragg peak. The collimated beam diameter (2 mm FWHM) is maintained out to the end of the Bragg peak.
Comparison Monte Carlo simulations predict a much reduced pristine Bragg peak for a higher energy
beam (100 MeV) extracted from an accelerator and then energy degraded using a range shifter.
Chromosome breaks and survival follow a depth-dependent curve that reproduces the behavior of the
proton beam depth-dose curve. Conclusions: These results demonstrate that the PPRP is capable of
producing small-diameter high-LET beams at useful depths in tissue. Similar to the new science that has
been enabled by image-guided precision X-ray radiation systems, the precision proton radiation platform
will enable a wide array of research crucial to advancing the use of proton and particle beams in radiation
therapy.
(PS3-47) Predicted risk of cardiac toxicity for Hodgkin lymphoma patients after carbon-ion therapy
2
1
1
2
versus proton therapy. John G. Eley ; Thomas Friedrich ; Kenneth Homann ; Marco Durante ; Michael
3
2
1
Scholz ; and Wayne D. Newhauser ;The University of Texas M. D. Anderson Cancer Center, Houston, TX ;
2
GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany ; and Louisiana State
University, Baton Rouge, LA
3
Hodgkin lymphoma (HL) patients treated with radiotherapy are susceptible to cardiovascular late
effects. The purpose of this study was to determine whether using carbon-ion therapy instead of proton
therapy would show a difference in the predicted risk of radiation-induced cardiac toxicity for HL patients.
We retrospectively selected 6 female HL patients who were previously treated with proton therapy. We
designed scanned proton and scanned carbon-ion treatment plans to deliver 36 Gy (RBE) to
supradiaphragmatic HL targets using a single anterior-posterior beam for each patient. For each plan, we
calculated the surviving fraction of cells on a voxelized grid throughout the whole heart, assuming a α/β
ratio of 3 Gy for all tissues in the heart. We calculated the ratio (R) of predicted normal tissue complication
probability (NTCP) in the heart using a relative seriality model for carbon-ion therapy versus proton
therapy. We found that target dose coverage was nearly identical, i.e., 36.1 ± 1.0 Gy (RBE) and 36.3 ± 1.8
Gy (RBE) for proton plans and carbon-ion plans, respectively. We found that the predicted NTCPs for
radiation-induced cardiac toxicity were highly variable among patients. Mean NTCPs were 5 ± 4 % and 4
± 3 % for proton and carbon-ion treatment, respectively. However, the ratio of predicted NTCP for carbon-
ion plans versus proton plans was less than unity for all patients, i.e., R = 0.66 ± 0.19, in favor of carbon-
ion therapy. Our findings are indicative that a lower risk of radiation-induced cardiac toxicity might be
expected for HL patients using carbon therapy instead of proton therapy.
(PS3-48) Conducting virtual clinical trials to evaluate hypofractionated radiotherapy for newly
diagnosed glioblastoma. David M. Corwin; Russell Rockne; and Kristin Swanson; Northwestern University,
Chicago, IL
Fractionated photon irradiation is an integral part of the standard-of-care for newly diagnosed
glioblastoma (GBM). Due to the limited benefit of current treatments and the lack of alternative options,
radiotherapy for GBM remains an area of active research as 42 of 56 open interventional clinical studies
for newly diagnosed GBMs involve this treatment modality. A recent article reviewed several studies
214 | P a g e
output of 10 Gy/min. Monte Carlo simulations predict a high-LET (>10 keV/μm) at the distal end of the
Bragg peak. The collimated beam diameter (2 mm FWHM) is maintained out to the end of the Bragg peak.
Comparison Monte Carlo simulations predict a much reduced pristine Bragg peak for a higher energy
beam (100 MeV) extracted from an accelerator and then energy degraded using a range shifter.
Chromosome breaks and survival follow a depth-dependent curve that reproduces the behavior of the
proton beam depth-dose curve. Conclusions: These results demonstrate that the PPRP is capable of
producing small-diameter high-LET beams at useful depths in tissue. Similar to the new science that has
been enabled by image-guided precision X-ray radiation systems, the precision proton radiation platform
will enable a wide array of research crucial to advancing the use of proton and particle beams in radiation
therapy.
(PS3-47) Predicted risk of cardiac toxicity for Hodgkin lymphoma patients after carbon-ion therapy
2
1
1
2
versus proton therapy. John G. Eley ; Thomas Friedrich ; Kenneth Homann ; Marco Durante ; Michael
3
2
1
Scholz ; and Wayne D. Newhauser ;The University of Texas M. D. Anderson Cancer Center, Houston, TX ;
2
GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany ; and Louisiana State
University, Baton Rouge, LA
3
Hodgkin lymphoma (HL) patients treated with radiotherapy are susceptible to cardiovascular late
effects. The purpose of this study was to determine whether using carbon-ion therapy instead of proton
therapy would show a difference in the predicted risk of radiation-induced cardiac toxicity for HL patients.
We retrospectively selected 6 female HL patients who were previously treated with proton therapy. We
designed scanned proton and scanned carbon-ion treatment plans to deliver 36 Gy (RBE) to
supradiaphragmatic HL targets using a single anterior-posterior beam for each patient. For each plan, we
calculated the surviving fraction of cells on a voxelized grid throughout the whole heart, assuming a α/β
ratio of 3 Gy for all tissues in the heart. We calculated the ratio (R) of predicted normal tissue complication
probability (NTCP) in the heart using a relative seriality model for carbon-ion therapy versus proton
therapy. We found that target dose coverage was nearly identical, i.e., 36.1 ± 1.0 Gy (RBE) and 36.3 ± 1.8
Gy (RBE) for proton plans and carbon-ion plans, respectively. We found that the predicted NTCPs for
radiation-induced cardiac toxicity were highly variable among patients. Mean NTCPs were 5 ± 4 % and 4
± 3 % for proton and carbon-ion treatment, respectively. However, the ratio of predicted NTCP for carbon-
ion plans versus proton plans was less than unity for all patients, i.e., R = 0.66 ± 0.19, in favor of carbon-
ion therapy. Our findings are indicative that a lower risk of radiation-induced cardiac toxicity might be
expected for HL patients using carbon therapy instead of proton therapy.
(PS3-48) Conducting virtual clinical trials to evaluate hypofractionated radiotherapy for newly
diagnosed glioblastoma. David M. Corwin; Russell Rockne; and Kristin Swanson; Northwestern University,
Chicago, IL
Fractionated photon irradiation is an integral part of the standard-of-care for newly diagnosed
glioblastoma (GBM). Due to the limited benefit of current treatments and the lack of alternative options,
radiotherapy for GBM remains an area of active research as 42 of 56 open interventional clinical studies
for newly diagnosed GBMs involve this treatment modality. A recent article reviewed several studies
214 | P a g e
