A Simulated Dosimetric Study of Contribution to Radiotherapy Accuracy by Fractional Image Guidance Protocol of Halcyon System

Wang, Haiyang; Huang, Yuliang; Hu, Qiaoqiao; Li, Chenguang; Liu, Hongjia; Wang, Xuejuan; Li, Weibo; Ma, Wenjun; Pu, Yichen; Du, Yixiao; Wu, Hao; Zhang, Yibao

doi:10.3389/fonc.2020.543147

Cited by 5 publications

(3 citation statements)

References 24 publications

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“…Tamihardja's [21] study also used CBCT-based off-line adaptive radiotherapy to assess the difference between actual dose and planned dose in prostate cancer. Wang's [22] study also compared dosimetry differences between daily and weekly CBCT using an MVCBCT-based off-line adaptive approach. Regarding algorithms, the AXB 13.5 calculates more accurately the air cavity than the traditional AAA algorithm calculation [23] .…”

Section: Discussionmentioning

confidence: 99%

Advantages and Robustness of Partial VMAT with Prone Position for Neoadjuvant Rectal Cancer Evaluated by CBCT-based Offline Adaptive Radiotherapy

Zhang

Peng

et al. 2023

Preprint

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Background and purpose: This study aims to explore the advantages and robustness of the partial arc combined with prone position planning technique for radiotherapy in rectal cancer patients. Adaptive radiotherapy is recalculated and accumulated on the synthesis CT (sCT) obtained by deformable image registration (DIR) between planning CT and cone beam CT (CBCT). Full and partial volume modulation arc therapy (VMAT) with the prone position on gastrointestinal and urogenital toxicity, based on the probability of normal tissue complications (NTCP) model in rectal cancer patients were evaluated. Materials and methods: Thirty-one patients were studied retrospectively. The contours of different structures were outlined in 155 CBCT images. First, full VMAT (F-VMAT) and partial VMAT (P-VMAT) planning techniques were processed and calculated using the same optimization constraints. The Acuros XB (AXB) algorithm was used in order to generate more realistic dose distributions and DVH, considering the air cavities. Second, the Velocity 4.0 software was used to fuse the planning CT and CBCT to obtain the sCT. Then, the AXB algorithm was used in the Eclipse 13.6 software to conduct re-calculation based on the sCT to obtain the corresponding dose. Furthermore, the LKB NTCP model was used to analyze its radiobiological side effects on the bladder and the bowel bag. Results: With a CTV coverage of 98%, when compared with F-VMAT, P-VMAT with the prone position technique can effectively reduce the mean dose of the bladder and the bowel bag. The LKB NTCP model showed that the P-VMAT combined with the prone planning technique resulted in a significantly lower complication probability of the bladder (1.88±2.08vs1.62±1.41, P=0.041) and the bowel bag (1.77 ± 2.90vs1.57 ± 2.36, P<0.001) than the F-VMAT. In terms of robustness, the P-VMAT is more robust than the F-VMAT, considering the fact that fewer changes were observed in the dose of the CTV, the bladder and the bowel bag. Conclusion: This study analyzed the advantages and robustness of the P-VMAT in the prone position from three aspects, based on the sCT fused by CBCT. Whether it is in regards to dosimetry, radiobiological effects or robustness, P-VMAT in the prone position has shown great advantages.

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Section: Discussionmentioning

confidence: 99%

Advantages and Robustness of Partial VMAT with Prone Position for Neoadjuvant Rectal Cancer Evaluated by CBCT-based Offline Adaptive Radiotherapy

Zhang

Peng

et al. 2023

Preprint

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“…Tamihardja et al [ 23 ] used CBCT-based off-line adaptive radiotherapy to assess the difference between actual dose and planned dose in prostate cancer. Wang et al [ 24 ] study also compared dosimetry differences between daily and weekly CBCT using an MVCBCT-based off-line adaptive approach. Regarding algorithms, the AXB 13.5 calculates more accurately the air cavity than the traditional AAA algorithm calculation [ 25 ].…”

Section: Discussionmentioning

confidence: 99%

Advantages and robustness of partial VMAT with prone position for neoadjuvant rectal cancer evaluated by CBCT-based offline adaptive radiotherapy

Zhang

Peng

et al. 2023

Radiat Oncol

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Background and purpose This study aims to explore the advantages and robustness of the partial arc combined with prone position planning technique for radiotherapy in rectal cancer patients. Adaptive radiotherapy is recalculated and accumulated on the synthesis CT (sCT) obtained by deformable image registration between planning CT and cone beam CT (CBCT). Full and partial volume modulation arc therapy (VMAT) with the prone position on gastrointestinal and urogenital toxicity, based on the probability of normal tissue complications (NTCP) model in rectal cancer patients were evaluated. Materials and methods Thirty-one patients were studied retrospectively. The contours of different structures were outlined in 155 CBCT images. First, full VMAT (F-VMAT) and partial VMAT (P-VMAT) planning techniques were designed and calculated using the same optimization constraints for each individual patient. The Acuros XB (AXB) algorithm was used in order to generate more realistic dose distributions and DVH, considering the air cavities. Second, the Velocity 4.0 software was used to fuse the planning CT and CBCT to obtain the sCT. Then, the AXB algorithm was used in the Eclipse 15.6 software to conduct re-calculation based on the sCT to obtain the corresponding dose. Furthermore, the NTCP model was used to analyze its radiobiological side effects on the bladder and the bowel bag. Results With a CTV coverage of 98%, when compared with F-VMAT, P-VMAT with the prone position technique can effectively reduce the mean dose of the bladder and the bowel bag. The NTCP model showed that the P-VMAT combined with the prone planning technique resulted in a significantly lower complication probability of the bladder (1.88 ± 2.08 vs 1.62 ± 1.41, P = 0.041) and the bowel bag (1.28 ± 1.70 vs 0.95 ± 1.52, P < 0.001) than the F-VMAT. In terms of robustness, P-VMAT was more robust than F-VMAT, considering that less dose and NTCP variation was observed in the CTV, bladder and bowel bag. Conclusion This study analyzed the advantages and robustness of the P-VMAT in the prone position from three aspects, based on the sCT fused by CBCT. Whether it is in regards to dosimetry, radiobiological effects or robustness, P-VMAT in the prone position has shown comparative advantages.

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“…The protocol of imaging frequency varies among centers to balance the treatment efficiency and accuracy. The unknown remaining fractions may result in unexpected dose deviation and potential tumor recurrence [ 8 ]. For this purpose, we aimed to study the sensitivity of highly optimized VMAT plans to geometry deviation to make a more complete description of dose delivery for complex plans.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of plan robustness on the dosimetry of volumetric arc radiotherapy (VMAT) with set-up uncertainty in Nasopharyngeal carcinoma (NPC) radiotherapy

Ding

Xiang

et al. 2022

Radiat Oncol

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Purpose To evaluate the sensitivity to set up the uncertainty of VMAT plans in Nasopharyngeal carcinoma (NPC) treatment by proposing a plan robustness evaluation method. Methods 10 patients were selected for this study. A 2-arc volumetric-modulated arc therapy (VMAT) plan was generated for each patient using Varian Eclipse (13.6 Version) treatment planning system (TPS). 5 uncertainty plans (U-plans) were recalculated based on the first 5 times set-up errors acquired from cone-beam computer tomography (CBCT). The dose differences of the original plan and perturbed plan corresponded to the plan robustness for the structure. Tumor control probability (TCP) and normal tissues complication probability (NTCP) were calculated for biological evaluation. Results The mean dose differences of D98% and D95% (ΔD98% and ΔD95%) of PTVp were respectively 3.30 Gy and 2.02 Gy. The ΔD98% and ΔD95% of CTVp were 1.12 Gy and 0.58 Gy. The ΔD98% and ΔD95% of CTVn were 1.39 Gy and 1.03 Gy, distinctively lower than those in PTVn (2.8 Gy and 2.0 Gy). The CTV-to-PTV margin increased the robustness of CTVs. The ΔD98% and ΔD95% of GTVp were 0.56 Gy and 0.33 Gy. GTVn exhibited strong robustness with little variation of D98% (0.64 Gy) and D95% (0.39 Gy). No marked mean dose variations of Dmean were seen. The mean reduction of TCP (ΔTCP) in GTVp and CTVp were respectively 0.4% and 0.3%. The mean ΔTCPs of GTVn and CTVn were 0.92% and 1.3% respectively. The CTV exhibited the largest ΔTCP (2.2%). In OARs, the brain stem exhibited weak robustness due to their locations in the vicinity of PTV. Bilateral parotid glands were sensitive to set-up uncertainty with a mean reduction of NTCP (ΔNTCP) of 6.17% (left) and 7.70% (right). The Dmax of optical nerves and lens varied slightly. Conclusion VMAT plans had a strong sensitivity to set-up uncertainty in NPC radiotherapy, with increasing risk of underdose of tumor and overdose of vicinal OARs. We proposed an effective method to evaluate the plan robustness of VMAT plans. Plan robustness and complexity should be taken into account in photon radiotherapy.

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A Simulated Dosimetric Study of Contribution to Radiotherapy Accuracy by Fractional Image Guidance Protocol of Halcyon System

Cited by 5 publications

References 24 publications

Advantages and Robustness of Partial VMAT with Prone Position for Neoadjuvant Rectal Cancer Evaluated by CBCT-based Offline Adaptive Radiotherapy

Advantages and Robustness of Partial VMAT with Prone Position for Neoadjuvant Rectal Cancer Evaluated by CBCT-based Offline Adaptive Radiotherapy

Advantages and robustness of partial VMAT with prone position for neoadjuvant rectal cancer evaluated by CBCT-based offline adaptive radiotherapy

Evaluation of plan robustness on the dosimetry of volumetric arc radiotherapy (VMAT) with set-up uncertainty in Nasopharyngeal carcinoma (NPC) radiotherapy

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