PURPOSE: The benefit of using dedicated in-beam positron emission tomography (PET) detectors in the treatment room instead of commercial tomographs nearby is an open question. This work quantitatively compares the measurable signal for in-beam and offline PET imaging, taking into account realistic acquisition strategies at different ion beam facilities. Both scenarios of pulsed and continuous irradiation from synchrotron and cyclotron accelerators are considered, because of their widespread use in most carbon ion and proton therapy centers. METHODS AND MATERIALS: A mathematical framework is introduced to compare the time-dependent amount and spatial distribution of decays from irradiation-induced isotope production. The latter is calculated with Monte Carlo techniques for real proton treatments of head-and-neck and paraspinal tumors. Extrapolation to carbon ion irradiation is based on results of previous phantom experiments. Biologic clearance is modeled taking into account available data from previous animal and clinical studies. RESULTS: Ratios between the amount of physical decays available for in-beam and offline detection range from 40% to 60% for cyclotron-based facilities, to 65% to 110% (carbon ions) and 94% to 166% (protons) at synchrotron-based facilities, and increase when including biologic clearance. Spatial distributions of decays during irradiation exhibit better correlation with the dose delivery and reduced influence of biologic processes. CONCLUSIONS: In-beam imaging can be advantageous for synchrotron-based facilities, provided that efficient PET systems enabling detection of isotope decays during beam extraction are implemented. For very short (<2 min) irradiation times at cyclotron-based facilities, a few minutes of acquisition time after the end of irradiation are needed for counting statistics, thus affecting patient throughput.
PURPOSE: The benefit of using dedicated in-beam positron emission tomography (PET) detectors in the treatment room instead of commercial tomographs nearby is an open question. This work quantitatively compares the measurable signal for in-beam and offline PET imaging, taking into account realistic acquisition strategies at different ion beam facilities. Both scenarios of pulsed and continuous irradiation from synchrotron and cyclotron accelerators are considered, because of their widespread use in most carbon ion and proton therapy centers. METHODS AND MATERIALS: A mathematical framework is introduced to compare the time-dependent amount and spatial distribution of decays from irradiation-induced isotope production. The latter is calculated with Monte Carlo techniques for real proton treatments of head-and-neck and paraspinal tumors. Extrapolation to carbon ion irradiation is based on results of previous phantom experiments. Biologic clearance is modeled taking into account available data from previous animal and clinical studies. RESULTS: Ratios between the amount of physical decays available for in-beam and offline detection range from 40% to 60% for cyclotron-based facilities, to 65% to 110% (carbon ions) and 94% to 166% (protons) at synchrotron-based facilities, and increase when including biologic clearance. Spatial distributions of decays during irradiation exhibit better correlation with the dose delivery and reduced influence of biologic processes. CONCLUSIONS: In-beam imaging can be advantageous for synchrotron-based facilities, provided that efficient PET systems enabling detection of isotope decays during beam extraction are implemented. For very short (<2 min) irradiation times at cyclotron-based facilities, a few minutes of acquisition time after the end of irradiation are needed for counting statistics, thus affecting patient throughput.
Authors: Nan Qin; Marco Pinto; Zhen Tian; Georgios Dedes; Arnold Pompos; Steve B Jiang; Katia Parodi; Xun Jia Journal: Phys Med Biol Date: 2017-01-31 Impact factor: 3.609
Authors: Xuping Zhu; Samuel España; Juliane Daartz; Norbert Liebsch; Jinsong Ouyang; Harald Paganetti; Thomas R Bortfeld; Georges El Fakhri Journal: Phys Med Biol Date: 2011-06-15 Impact factor: 3.609
Authors: Kira Grogg; Nathaniel M Alpert; Xuping Zhu; Chul Hee Min; Mauro Testa; Brian Winey; Marc D Normandin; Helen A Shih; Harald Paganetti; Thomas Bortfeld; Georges El Fakhri Journal: Int J Radiat Oncol Biol Phys Date: 2015-03-25 Impact factor: 7.038
Authors: Kira Grogg; Xuping Zhu; Chul Hee Min; Brian Winey; Thomas Bortfeld; Harald Paganetti; Helen A Shih; Georges El Fakhri Journal: IEEE Trans Nucl Sci Date: 2013-10 Impact factor: 1.679
Authors: Jongmin Cho; Geoffrey Ibbott; Michael Gillin; Carlos Gonzalez-Lepera; Chul Hee Min; Xuping Zhu; Georges El Fakhri; Harald Paganetti; Osama Mawlawi Journal: Phys Med Biol Date: 2013-05-16 Impact factor: 3.609
Authors: Chul Hee Min; Xuping Zhu; Brian A Winey; Kira Grogg; Mauro Testa; Georges El Fakhri; Thomas R Bortfeld; Harald Paganetti; Helen A Shih Journal: Int J Radiat Oncol Biol Phys Date: 2013-02-04 Impact factor: 7.038