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 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 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.

Intensity-modulated proton therapy for nasopharyngeal carcinoma: Decreased radiation dose to normal structures and encouraging clinical outcomes

Head & Neck ◽  
2015 ◽  
Vol 38 (S1) ◽  
pp. E1886-E1895 ◽  
Author(s):  
Gary D. Lewis ◽  
Emma B. Holliday ◽  
Esengul Kocak-Uzel ◽  
Mike Hernandez ◽  
Adam S. Garden ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Radiation Dose ◽  
Clinical Outcomes ◽  
Proton Therapy ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated

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 Post-Irradiation Sinus Mucosa Disease in Nasopharyngeal Carcinoma Patients Treated with Intensity-Modulated Proton Therapy

Cancers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 225
Author(s):  
Pei-Wen Wu ◽  
Chien-Chia Huang ◽  
Yun-Shien Lee ◽  
Yung-Chih Chou ◽  
Kang-Hsing Fan ◽  
...  
Keyword(s):  
Proton Therapy ◽  
Nasopharyngeal Cancer ◽  
Post Irradiation ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Target Volumes ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri ◽  
Sinus Mucosa

In the past decade, patients with nasopharyngeal cancer (NPC) have been deemed candidates for proton radiotherapy, due to the large and comprehensive target volumes and the necessity for the retention of the surrounding healthy tissues. In this study, we aimed to compare the incidence and severity of post-irradiation sinusitis by detecting sinus mucosa diseases (SMDs) via the magnetic resonance imaging (MRI) of patients with NPC after intensity-modulated proton therapy (IMPT) and volume-modulated arc therapy (VMAT). A total of 53 patients in the IMPT group and 54 patients in the VMAT group were enrolled in this study. There were significantly lower endoscopic scores and Lund–Mackay staging scores determined from MRI scans in the IMPT group during different follow-up periods. For the most vulnerable sinuses, the incidence and severity of SMD were the highest during the third post-radiotherapy month in both groups. These decreased steadily, and there was no significant increase in the incidence and severity of SMD during the second post-radiotherapy year in the IMPT group. Our data show that NPC patients with IMPT have a significantly lower incidence and decreased severity of SMD than those with VMAT. A better and faster recovery of sinonasal function after radiotherapy in the IMPT group was also observed.

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
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