scholarly journals The Potential Role of Intensity-Modulated Proton Therapy in Hepatic Carcinoma in Mitigating the Risk of Dose De-Escalation

2020 ◽  
Vol 19 ◽  
pp. 153303382098041
Author(s):  
Luca Cozzi ◽  
Tiziana Comito ◽  
Mauro Loi ◽  
Antonella Fogliata ◽  
Ciro Franzese ◽  
...  
Keyword(s):  
At Risk ◽  
Proton Therapy ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Number Of Patients ◽  
Target Volumes ◽  
Dosimetric Analysis

Purpose: To investigate the role of intensity-modulated proton therapy (IMPT) for hepatocellular carcinoma (HCC) patients to be treated with stereotactic body radiation therapy (SBRT) in a risk-adapted dose prescription regimen. Methods: A cohort of 30 patients was retrospectively selected as “at-risk” of dose de-escalation due to the proximity of the target volumes to dose-limiting healthy structures. IMPT plans were compared to volumetric modulated arc therapy (VMAT) RapidArc (RA) plans. The maximum dose prescription foreseen was 75 Gy in 3 fractions. The dosimetric analysis was performed on several quantitative metrics on the target volumes and organs at risk to identify the relative improvement of IMPT over VMAT and to determine if IMPT could mitigate the need of dose reduction and quantify the consequent potential patient accrual rate for protons. Results: IMPT and VMAT plans resulted in equivalent target dose distributions: both could ensure the required coverage for CTV and PTV. Systematic and significant improvements were observed with IMPT for all organs at risk and metrics. An average gain of 9.0 ± 11.6, 8.5 ± 7.7, 5.9 ± 7.1, 4.2 ± 6.4, 8.9 ± 7.1, 6.7 ± 7.5 Gy was found in the near-to-maximum doses for the ribs, chest wall, heart, duodenum, stomach and bowel bag respectively. Twenty patients violated one or more binding constraints with RA, while only 2 with IMPT. For all these patients, some dose de-intensification would have been required to respect the constraints. For photons, the maximum allowed dose ranged from 15.0 to 20.63 Gy per fraction while for the 2 proton cases it would have been 18.75 or 20.63 Gy. Conclusion: The results of this in-silico planning study suggests that IMPT might result in advantages compared to photon-based VMAT for HCC patients to be treated with ablative SBRT. In particular, the dosimetric characteristics of protons may avoid the need for dose de-escalation in a risk-adapted prescription regimen for those patients with lesions located in proximity of dose-limiting healthy structures. Depending on the selection thresholds, the number of patients eligible for treatment at the full dose can be significantly increased with protons.

scholarly journals Dosimetric Comparison of Helical Tomotherapy, Volumetric-Modulated Arc Therapy, and Intensity-Modulated Proton Therapy for Angiosarcoma of the Scalp

2021 ◽  
Vol 20 ◽  
pp. 153303382098586
Author(s):  
Tomoki Mizuno ◽  
Natsuo Tomita ◽  
Taiki Takaoka ◽  
Masashi Tomida ◽  
Hiroshi Fukuma ◽  
...  
Keyword(s):  
Proton Therapy ◽  
Helical Tomotherapy ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Target Volume ◽  
The Other ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Arc Therapy ◽  
Dose Constraint

Objective: We compared radiotherapy plans among helical tomotherapy (HT), volumetric-modulated arc therapy (VMAT), and intensity-modulated proton therapy (IMPT) for angiosarcoma of the scalp (AS). Methods: We conducted a planning study for 19 patients with AS. The clinical target volume (CTV) 1 and CTV2 were defined as the gross tumor volume with a specific margin and total scalp, respectively. For HT and VMAT, the planning target volume (PTV) 1 and PTV2 were defined as CTV1 and CTV2 with 0.5-cm margins, respectively. For IMPT, robust optimization was used instead of a CTV-PTV margin (i.e. CTV robust). The targets of the HT and VMAT plans were the PTV, whereas the IMPT plans targeted the CTV robust. In total, 70 Gy and 56 Gy were prescribed as the D95% (i.e. dose to 95% volume) of PTV1 (or CTV1 robust) and PTV2 (or CTV2 robust), respectively, using the simultaneous integrated boost (SIB) technique. Other constraint goals were also defined for the target and organs at risk (OAR). Results: All dose constraint parameters for the target and OAR met the goals within the acceptable ranges for the 3 techniques. The coverage of the targets replaced by D95% and D98% were almost equivalent among the 3 techniques. The homogeneity index of PTV1 or CTV1 robust was equivalent among the 3 techniques, whereas that of PTV2 or CTV2 robust was significantly higher in the IMPT plans than in the other plans. IMPT reduced the Dmean of the brain and hippocampus by 49% to 95%, and the Dmax of the spinal cord, brainstem, and optic pathway by 70% to 92% compared with the other techniques. Conclusion: The 3 techniques with SIB methods provided sufficient coverage and satisfactory homogeneity for the targets, but IMPT achieved the best OAR sparing.

scholarly journals Robust intensity-modulated proton therapy to reduce high linear energy transfer in organs at risk

2017 ◽  
Vol 44 (12) ◽  
pp. 6138-6147 ◽  
Author(s):  
Yu An ◽  
Jie Shan ◽  
Samir H. Patel ◽  
William Wong ◽  
Steven E. Schild ◽  
...  
Keyword(s):  
At Risk ◽  
Energy Transfer ◽  
Proton Therapy ◽  
Linear Energy Transfer ◽  
Organs At Risk ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
High Linear Energy Transfer

scholarly journals Assessment of Knowledge-Based Planning for Prostate Intensity Modulated Proton Therapy

2021 ◽  
Author(s):  
Yihang Xu ◽  
Nellie Brovold ◽  
Jonathan Cyriac ◽  
Elizabeth Bossart ◽  
Kyle Padgett ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Proton Therapy ◽  
Volumetric Modulated Arc Therapy ◽  
Model Quality ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Knowledge Based ◽  
Knowledge Based Planning ◽  
Organ At Risk

Abstract Purpose To assess the performance of a proton-specific knowledge based planning (KBPP) model in creation of robustly optimized intensity-modulated proton therapy (IMPT) plans for treatment of patients with prostate cancer. Materials and Methods Forty-five patients with localized prostate cancer, who had previously been treated with volumetric modulated arc therapy, were selected and replanned with robustly optimized IMPT. A KBPP model was generated from the results of 30 of the patients, and the remaining 15 patient results were used for validation. The KBPP model quality and accuracy were evaluated with the model-provided organ-at-risk regression plots and metrics. The KBPP quality was also assessed through comparison of expert and KBPP-generated IMPT plans for target coverage and organ-at-risk sparing. Results The resulting R2 (mean ± SD, 0.87 ± 0.07) between dosimetric and geometric features, as well as the χ2 test (1.17 ± 0.07) between the original and estimated data, showed the model had good quality. All the KBPP plans were clinically acceptable. Compared with the expert plans, the KBPP plans had marginally higher dose-volume indices for the rectum V65Gy (0.8% ± 2.94%), but delivered a lower dose to the bladder (−1.06% ± 2.9% for bladder V65Gy). In addition, KBPP plans achieved lower hotspot (−0.67Gy ± 2.17Gy) and lower integral dose (−0.09Gy ± 0.3Gy) than the expert plans did. Moreover, the KBPP generated better plans that demonstrated slightly greater clinical target volume V95 (0.1% ± 0.68%) and lower homogeneity index (−1.13 ± 2.34). Conclusions The results demonstrated that robustly optimized IMPT plans created by the KBPP model are of high quality and are comparable to expert plans. Furthermore, the KBPP model can generate more-robust and more-homogenous plans compared with those of expert plans. More studies need to be done for the validation of the proton KBPP model at more-complicated treatment sites.

scholarly journals Comparison of intensity modulated photon therapy and intensity modulated proton therapy plans for prostate cancer

2015 ◽  
Vol 18 (3) ◽  
pp. 93-100
Author(s):  
Tu Thi Cam Nguyen ◽  
Nhon Van Mai ◽  
Binh Thai Nguyen
Keyword(s):  
At Risk ◽  
Proton Therapy ◽  
Organs At Risk ◽  
X Rays ◽  
Work Intensity ◽  
Normal Tissues ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Dose Volume ◽  
Treatment Plans

Nowadays, traditional radiation therapy using x-rays is still the most common type of external exposure in curing cancer. However, the persisting problem is that significant dose delivered to normal tissues because of the characteristics of interaction of photons with matter even with the most advanced delivery techniques such as IMRT, IGRT, etc. Proton therapy is not only the technique producing better conformity to target but also better sparing to organs at risk. In this work, intensity modulated proton therapy (IMPT) and intensity modulated photon therapy (IMRT) plans are generated for a prostate patient. The evaluation and comparison of the two treatment plans were performed in term of physical quantity based on Dose Volume Histogram (DVH) and dose statistics for both target and organs at risk. The results of our study show that IMPT could be beneficial compared to IMRT with 5 fields. The doses to intestine and bladder are low resulting in possibly reducing side effects and second malignancies

scholarly journals Inter-fraction robustness of intensity-modulated proton therapy in the post-operative treatment of oropharyngeal and oral cavity squamous cell carcinomas

2020 ◽  
Vol 93 (1107) ◽  
pp. 20190638 ◽  
Author(s):  
Christina Hague ◽  
Marianne Aznar ◽  
Lei Dong ◽  
Alireza Fotouhi-Ghiam ◽  
Lip Wai Lee ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Proton Therapy ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Cone Beam Ct ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Target Volumes ◽  
Setup Variation ◽  
Relative Change

Objective: To evaluate dosimetric consequences of inter-fraction setup variation and anatomical changes in patients receiving multifield optimised (MFO) intensity modulated proton therapy for post-operative oropharyngeal (OPC) and oral cavity (OCC) cancers. Methods: Six patients receiving MFO for post-operative OPC and OCC were evaluated. Plans were robustly optimised to clinical target volumes (CTVs) using 3 mm setup and 3.5% range uncertainty. Weekly online cone beam CT (CBCT) were performed. Planning CT was deformed to the CBCT to create virtual CTs (vCTs) on which the planned dose was recalculated. vCT plan robustness was evaluated using a setup uncertainty of 1.5 mm and range uncertainty of 3.5%. Target coverage, D95%, and hotspots, D0.03cc, were evaluated for each uncertainty along with the vCT-calculated nominal plan. Mean dose to organs at risk (OARs) for the vCT-calculated nominal plan and relative % change in weight from baseline were evaluated. Results: Robustly optimised plans in post-operative OPC and OCC patients are robust against inter-fraction setup variations and range uncertainty. D0.03cc in the vCT-calculated nominal plans were clinically acceptable across all plans. Across all patients D95% in the vCT-calculated nominal treatment plan was at least 100% of the prescribed dose. No patients lost ≥10% weight from baseline. Mean dose to the OARs and max dose to the spinal cord remained within tolerance. Conclusion: MFO plans in post-operative OPC and OCC patients are robust to inter-fraction uncertainties in setup and range when evaluated over multiple CT scans without compromising OAR mean dose. Advances in knowledge: This is the first paper to evaluate inter-fraction MFO plan robustness in post-operative head and neck treatment.

scholarly journals Significant Reduction in Vertebral Artery Dose by Intensity Modulated Proton Therapy: A Pilot Study for Nasopharyngeal Carcinoma

2021 ◽  
Vol 11 (8) ◽  
pp. 822
Author(s):  
Yun-Hsuan Lin ◽  
Jen-Yu Cheng ◽  
Bing-Shen Huang ◽  
Sheng-Dean Luo ◽  
Wei-Che Lin ◽  
...  
Keyword(s):  
Pilot Study ◽  
Nasopharyngeal Carcinoma ◽  
Vertebral Artery ◽  
Proton Therapy ◽  
Organs At Risk ◽  
Patient Treatment ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Adequate Dose ◽  
Target Volumes

Intensity modulated proton therapy (IMPT) with the vertebral artery (VA)-sparing technique has been initially proposed in our institution. This pilot study was conducted to compare the dose to VAs between IMPT and volumetric-modulated arc therapy (VMAT) for patients with nasopharyngeal carcinoma (NPC). A total of six patients with NPC treated by IMPT were enrolled in the study. Target volumes and organs at risk (OARs) were delineated, including 12 samples of right and left VAs, respectively, for each patient. Treatment planning by IMPT and dual-arc VMAT was carried out for comparison. The IMPT plan significantly reduced VA mean dose, V10, V20, V30, V40, and V50, compared to the VMAT plan in all 12 samples (p < 0.001). The average mean dose to VAs for IMPT was 35.2% (23.4–46.9%), which was less compared to VMAT (p < 0.001). Adequate dose coverage was achieved with both IMPT and VMAT plans for three different dose levels of target volumes for all patients. IMPT significantly reduces VA dose while maintaining adequate dose coverage of all target volumes. For patients with head and neck cancer who seek to preserve their blood flow to the brain in order to decrease late vascular and neurologic sequelae, IMPT should be considered. A prospective study with longer follow-up is ongoing to confirm our preliminary results.

scholarly journals Intensity-modulated proton therapy decreases dose to organs at risk in low-grade glioma patients: results of a multicentric in silico ROCOCO trial

2018 ◽  
Vol 58 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Daniëlle B. P. Eekers ◽  
Erik Roelofs ◽  
Macarena Cubillos-Mesías ◽  
Charles Niël ◽  
Robert Jan Smeenk ◽  
...  
Keyword(s):  
At Risk ◽  
Proton Therapy ◽  
In Silico ◽  
Organs At Risk ◽  
Low Grade Glioma ◽  
Low Grade ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated

scholarly journals Sparing Cardiac Substructures With Optimized Volumetric Modulated Arc Therapy and Intensity Modulated Proton Therapy in Thoracic Radiation for Locally Advanced Non-small Cell Lung Cancer

2019 ◽  
Vol 9 (5) ◽  
pp. e473-e481 ◽  
Author(s):  
Matthew J. Ferris ◽  
Katherine S. Martin ◽  
Jeffrey M. Switchenko ◽  
Oluwatosin A. Kayode ◽  
Jonathan Wolf ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Proton Therapy ◽  
Locally Advanced ◽  
Volumetric Modulated Arc Therapy ◽  
Small Cell ◽  
Small Cell Lung ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Thoracic Radiation ◽  
Arc Therapy
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