Online Palliative Radiotherapy Planning And Treatment Using Cone-Beam Computerized Tomography (Cbct)

Purpose/Objective(s)CBCT image quality has advanced sufficiently for it to be potentially useful for radiotherapy (RT) treatment planning in selected clinical circumstances. The ability to acquire planning images directly from the treatment unit provides the opportunity to integrate the multi-step planning to treatment process into a single step. The purpose of this study was to facilitate palliative RT and investigate the one step planning and treatment process facilitated using on board volumetric imaging with CBCT.Materials/MethodsA prospective sequential three-phase study design was used. The objectives were to evaluate in phase A: the image quality for target definition; phase B: plan quality; and phase C: efficiency of the process in practice. Patients receiving palliative radiotherapy using ≤2 beam techniques were eligible. Patients were stratified by anatomical site: spine, lung, and abdomen. Phase C study was limited to palliative RT of bone metastases patients. For all patients, both conventional planning CT and CBCT images were acquired. In Phase A, target definition on the CBCT dataset was performed offline. In Phase B, the CBCT planning process was performed online within the clinical environment although patients continued to be treated using conventional planning CT plan (PCT). In Phase C, the online planning process was used clinically. The PCT was used for quality assurance purposes only. Accuracy of target definition, dosimetric coverage of PTV, time to complete the process, and patient satisfaction were evaluated and compared.ResultsSixty-two patients participated in the study (phase A - 9, phase B - 43, phase C - 10). Phase A established the accuracy of CBCT for the definition of GTV and treatment fields. The mean radiation field area overlap, over and under coverage was 80(±7)%, 11(±7)%, and 11(±8)% respectively. In phase B, the quality of target and field definition was similar. Overlap, over and under coverage were 84(±15)%, 15(±19)%, and 17(±15)% respectively. The degree of overlap was highest for spine 89(±13)%, followed by lung 82(±15)%, and abdomen 80(±15)%. Coverage of the PCT defined PTV by the CBCT treatment plan (≥90% isodose) was high, with spine 93 (±11)%, abdomen 92(±5)%, and lung 89(±15)%. In 2 abdomen cases however, the image quality was insufficient for target definition. Phase C showed that the online process was clinically applicable with a mean time of 39(±7) min. As the process was refined, the time improved from a mean of 46 min (first 3 patients) to 31 min (last 3 patients).ConclusionsOur study demonstrated that CBCT based on line planning and treatment is feasible and clinically applicable for selective patients receiving palliative radiotherapy. This streamlined process can significantly improve the quality of care for palliative patients. Purpose/Objective(s)CBCT image quality has advanced sufficiently for it to be potentially useful for radiotherapy (RT) treatment planning in selected clinical circumstances. The ability to acquire planning images directly from the treatment unit provides the opportunity to integrate the multi-step planning to treatment process into a single step. The purpose of this study was to facilitate palliative RT and investigate the one step planning and treatment process facilitated using on board volumetric imaging with CBCT. CBCT image quality has advanced sufficiently for it to be potentially useful for radiotherapy (RT) treatment planning in selected clinical circumstances. The ability to acquire planning images directly from the treatment unit provides the opportunity to integrate the multi-step planning to treatment process into a single step. The purpose of this study was to facilitate palliative RT and investigate the one step planning and treatment process facilitated using on board volumetric imaging with CBCT. Materials/MethodsA prospective sequential three-phase study design was used. The objectives were to evaluate in phase A: the image quality for target definition; phase B: plan quality; and phase C: efficiency of the process in practice. Patients receiving palliative radiotherapy using ≤2 beam techniques were eligible. Patients were stratified by anatomical site: spine, lung, and abdomen. Phase C study was limited to palliative RT of bone metastases patients. For all patients, both conventional planning CT and CBCT images were acquired. In Phase A, target definition on the CBCT dataset was performed offline. In Phase B, the CBCT planning process was performed online within the clinical environment although patients continued to be treated using conventional planning CT plan (PCT). In Phase C, the online planning process was used clinically. The PCT was used for quality assurance purposes only. Accuracy of target definition, dosimetric coverage of PTV, time to complete the process, and patient satisfaction were evaluated and compared. A prospective sequential three-phase study design was used. The objectives were to evaluate in phase A: the image quality for target definition; phase B: plan quality; and phase C: efficiency of the process in practice. Patients receiving palliative radiotherapy using ≤2 beam techniques were eligible. Patients were stratified by anatomical site: spine, lung, and abdomen. Phase C study was limited to palliative RT of bone metastases patients. For all patients, both conventional planning CT and CBCT images were acquired. In Phase A, target definition on the CBCT dataset was performed offline. In Phase B, the CBCT planning process was performed online within the clinical environment although patients continued to be treated using conventional planning CT plan (PCT). In Phase C, the online planning process was used clinically. The PCT was used for quality assurance purposes only. Accuracy of target definition, dosimetric coverage of PTV, time to complete the process, and patient satisfaction were evaluated and compared. ResultsSixty-two patients participated in the study (phase A - 9, phase B - 43, phase C - 10). Phase A established the accuracy of CBCT for the definition of GTV and treatment fields. The mean radiation field area overlap, over and under coverage was 80(±7)%, 11(±7)%, and 11(±8)% respectively. In phase B, the quality of target and field definition was similar. Overlap, over and under coverage were 84(±15)%, 15(±19)%, and 17(±15)% respectively. The degree of overlap was highest for spine 89(±13)%, followed by lung 82(±15)%, and abdomen 80(±15)%. Coverage of the PCT defined PTV by the CBCT treatment plan (≥90% isodose) was high, with spine 93 (±11)%, abdomen 92(±5)%, and lung 89(±15)%. In 2 abdomen cases however, the image quality was insufficient for target definition. Phase C showed that the online process was clinically applicable with a mean time of 39(±7) min. As the process was refined, the time improved from a mean of 46 min (first 3 patients) to 31 min (last 3 patients). Sixty-two patients participated in the study (phase A - 9, phase B - 43, phase C - 10). Phase A established the accuracy of CBCT for the definition of GTV and treatment fields. The mean radiation field area overlap, over and under coverage was 80(±7)%, 11(±7)%, and 11(±8)% respectively. In phase B, the quality of target and field definition was similar. Overlap, over and under coverage were 84(±15)%, 15(±19)%, and 17(±15)% respectively. The degree of overlap was highest for spine 89(±13)%, followed by lung 82(±15)%, and abdomen 80(±15)%. Coverage of the PCT defined PTV by the CBCT treatment plan (≥90% isodose) was high, with spine 93 (±11)%, abdomen 92(±5)%, and lung 89(±15)%. In 2 abdomen cases however, the image quality was insufficient for target definition. Phase C showed that the online process was clinically applicable with a mean time of 39(±7) min. As the process was refined, the time improved from a mean of 46 min (first 3 patients) to 31 min (last 3 patients). ConclusionsOur study demonstrated that CBCT based on line planning and treatment is feasible and clinically applicable for selective patients receiving palliative radiotherapy. This streamlined process can significantly improve the quality of care for palliative patients. Our study demonstrated that CBCT based on line planning and treatment is feasible and clinically applicable for selective patients receiving palliative radiotherapy. This streamlined process can significantly improve the quality of care for palliative patients.