1
|
Critchfield LS, Bernard ME, Randall ME, McGarry RC, Pokhrel D. A novel restricted single-isocenter stereotactic body radiotherapy (RESIST) method for synchronous multiple lung lesions to minimize setup uncertainties. Med Dosim 2021; 46:419-425. [PMID: 34148728 DOI: 10.1016/j.meddos.2021.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/01/2021] [Accepted: 05/18/2021] [Indexed: 10/21/2022]
Abstract
Treating multiple lung lesions synchronously using a single-isocenter volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) plan can improve treatment efficiency and patient compliance. However, due to set up uncertainty, aligning multiple lung tumors on a single daily cone beam CT (CBCT) image has shown clinically unacceptable loss of target(s) coverage. Herein, we propose a Restricted Single-Isocenter Stereotactic Body Radiotherapy (RESIST), an alternative treatment that mitigates patient setup uncertainties. Twenty-one patients with two lung lesions were treated with single-isocenter VMAT-SBRT using a 6MV-FFF beam to 54 Gy in 3 fractions (n = 7) or 50 Gy in 5 fractions (n = 14) prescribed to 70-80% isodose line. To minimize setup uncertainties, each plan was re-planned using the RESIST method, utilizing a single-isocenter placed at the patient's mediastinum. It allows for an individual plan to be created for each tumor, using the first plan as the base-dose for the second plan, while still allowing both tumors to be treated in the same session. The technique uses novel features in Eclipse, including dynamic conformal arc (DCA)-based dose and aperture shape controller before each VMAT optimization. RESIST plans provided better target dose conformity (p < 0.001) and gradient indices (p < 0.001) and lower dose to adjacent critical organs. Using RESIST to treat synchronous lung lesions with VMAT-SBRT significantly reduces plan complexity as demonstrated by smaller beam modulation factors (p < 0.001), without unreasonably increasing treatment time. RESIST reduces the chance of a geometric miss due by allowing CBCT matching of one tumor at a time. Placement of isocenter at the mediastinum avoids potential patient/gantry collisions, provides greater flexibility of noncoplanar arcs and eliminates the need for multiple couch movements during CBCT imaging. Efficacy of RESIST has been demonstrated for two lesions and can potentially be used for more lesions. Clinical implementation of this technique is ongoing.
Collapse
Affiliation(s)
- Lana Sanford Critchfield
- Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA
| | - Mark E Bernard
- Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA
| | - Marcus E Randall
- Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA
| | - Ronald C McGarry
- Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA
| | - Damodar Pokhrel
- Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA
| |
Collapse
|
2
|
Lee J, Kim JI, Ye SJ, Kim HJ, Carlson J, Park JM. Dosimetric effects of roll rotational setup errors on lung stereotactic ablative radiotherapy using volumetric modulated arc therapy. Br J Radiol 2015; 88:20140862. [PMID: 26369834 DOI: 10.1259/bjr.20140862] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE To evaluate the dosimetric effects of roll-rotational setup errors of stereotactic ablative radiotherapy (SABR) for lung cancer using volumetric modulated arc therapy (VMAT). METHODS A total of 23 lung SABR cases were evaluated retrospectively. Each of the planning CT images was intentionally rotated by ±1°, ±2° and ±3°. After that, to simulate the translational couch correction, rotated CT images were moved along the x, y and z axis to match the centroid of the target volume in the rotated CT images with that in the original CT images. The differences in D95% and V100% of the target volume, D0.35cc of spinal cord, D0.35cc and D5cc of oesophagus and V20Gy of lung between the original and the rotated CT images were calculated. RESULTS The average differences in D95% and V100% of target volume, D0.35cc of spinal cord, D0.35cc and D5cc of oesophagus and V20Gy of lung were -0.3% ± 0.4% and -0.7% ± 2.4%, 1.6 ± 27.9 cGy, -1.6 ± 37.6 cGy, 15.9 ± 25.3 cGy and 0.0% ± 0.1%, respectively. The dosimetric changes in organs at risk (OARs) near the target volume were sometimes considerable due to roll-rotational setup errors, despite the translational correction, and those were patient specific. CONCLUSION In the case of coplanar VMAT for lung SABR, dosimetric changes to the target volume due to roll-rotational setup errors could be compensated by translational correction, whereas those to the OARs could not in some cases. ADVANCES IN KNOWLEDGE Roll-rotational setup errors would increase the dose to OARs despite the translational correction.
Collapse
Affiliation(s)
- Jaegi Lee
- 1 Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Seoul National University Graduate School of Convergence Science and Technology, Seoul, Korea.,2 Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Jung-In Kim
- 2 Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Korea.,3 Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea.,4 Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.,5 Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, Korea
| | - Sung-Joon Ye
- 1 Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Seoul National University Graduate School of Convergence Science and Technology, Seoul, Korea.,3 Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea
| | - Hak Jae Kim
- 3 Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea.,4 Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.,6 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea
| | - Joel Carlson
- 1 Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Seoul National University Graduate School of Convergence Science and Technology, Seoul, Korea.,2 Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Jong Min Park
- 2 Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Korea.,3 Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea.,4 Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.,5 Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, Korea
| |
Collapse
|