BACKGROUND: Modern radiotherapy (RT) for lymphoma is highly personalized. While advanced imaging is largely employed to define limited treatment volumes, the use of proton pencil beam scanning (PBS) for highly conformal lymphoma RT is still in its infancy. Here, we assess the dosimetric benefits and feasibility of PBS for mediastinal lymphoma (ML). MATERIALS AND METHODS: Ten patients were planned using PBS for involved-site RT. The initial plans were calculated on the average four-dimensional computed tomography (4D-CT). PBS plans were compared with 3D conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and proton double scattering (DS). In order to evaluate the feasibility of PBS and the plan robustness against inter- and intra-fractional uncertainties, the 4D dose was calculated on initial and verification CTs. The deviation of planned dose from delivered dose was measured. The same proton beamline was used for all patients, while another beamline with larger spots was employed for patients with large motion perpendicular to the beam. RESULTS: PBS provided the lowest mean lung dose (MLD) and mean heart dose (MHD) for all patients in comparison with 3D-CRT, IMRT, and DS. For eight patients, internal target volume (ITV) D98% was degraded by <3%; and the MLD and MHD deviated by <10% of prescription over the course of treatment when the PBS field was painted twice in each session. For one patient with target motion perpendicular to the beam (>5 mm), the degradation of ITV D98% was 9%, which was effectively mitigated by employing large spots. One patient exhibited large dose degradation due to pericardial effusion, which required replanning across all modalities. CONCLUSIONS: This study demonstrates that PBS plans significantly reduce MLD and MHD relative to 3D-CRT, IMRT, and DS and identifies requirements for robust free-breathing ML PBS treatments, showing that PBS plan robustness can be maintained with repainting and/or large spots.
BACKGROUND: Modern radiotherapy (RT) for lymphoma is highly personalized. While advanced imaging is largely employed to define limited treatment volumes, the use of proton pencil beam scanning (PBS) for highly conformal lymphoma RT is still in its infancy. Here, we assess the dosimetric benefits and feasibility of PBS for mediastinal lymphoma (ML). MATERIALS AND METHODS: Ten patients were planned using PBS for involved-site RT. The initial plans were calculated on the average four-dimensional computed tomography (4D-CT). PBS plans were compared with 3D conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and proton double scattering (DS). In order to evaluate the feasibility of PBS and the plan robustness against inter- and intra-fractional uncertainties, the 4D dose was calculated on initial and verification CTs. The deviation of planned dose from delivered dose was measured. The same proton beamline was used for all patients, while another beamline with larger spots was employed for patients with large motion perpendicular to the beam. RESULTS:PBS provided the lowest mean lung dose (MLD) and mean heart dose (MHD) for all patients in comparison with 3D-CRT, IMRT, and DS. For eight patients, internal target volume (ITV) D98% was degraded by <3%; and the MLD and MHD deviated by <10% of prescription over the course of treatment when the PBS field was painted twice in each session. For one patient with target motion perpendicular to the beam (>5 mm), the degradation of ITV D98% was 9%, which was effectively mitigated by employing large spots. One patient exhibited large dose degradation due to pericardial effusion, which required replanning across all modalities. CONCLUSIONS: This study demonstrates that PBS plans significantly reduce MLD and MHD relative to 3D-CRT, IMRT, and DS and identifies requirements for robust free-breathing ML PBS treatments, showing that PBS plan robustness can be maintained with repainting and/or large spots.
Authors: Bouthaina Shbib Dabaja; Bradford S Hoppe; John P Plastaras; Wayne Newhauser; Katerina Rosolova; Stella Flampouri; Radhe Mohan; N George Mikhaeel; Youlia Kirova; Lena Specht; Joachim Yahalom Journal: Blood Date: 2018-08-14 Impact factor: 22.113
Authors: He J Zhu; Bradford S Hoppe; Stella Flampouri; Debbie Louis; John Pirris; R Charles Nichols; Randal H Henderson; Catherine E Mercado Journal: Transl Lung Cancer Res Date: 2018-04
Authors: James E Younkin; Danairis Hernandez Morales; Jiajian Shen; Xiaoning Ding; Joshua B Stoker; Nathan Y Yu; Terence T Sio; Thomas B Daniels; Martin Bues; Mirek Fatyga; Steven E Schild; Wei Liu Journal: Med Phys Date: 2021-07-29 Impact factor: 4.506
Authors: B S Hoppe; C E Hill-Kayser; Y D Tseng; S Flampouri; H M Elmongy; O Cahlon; N P Mendenhall; A Maity; L A McGee; J P Plastaras Journal: Ann Oncol Date: 2017-09-01 Impact factor: 32.976
Authors: Lillie O'steen; Jason Bellardini; James Cury; Lisa Jones; Vandana K Seeram; Nancy P Mendenhall; Bradford S Hoppe Journal: Int J Part Ther Date: 2019-03-21