The purpose of this study was to examine if the use of a bolus helmet when treating the head with intensity modulated proton therapy (IMPT) will maintain organs at risk (OAR) sparing while improving the clinical target volume (CTV) coverage. A bolus helmet is a device that aims to improve on the traditionally used range shifter in proton therapy by improving dose distribution characteristics. Ten patients were retrospectively selected who had 2 separate treatment planning scans performed, a scan with the bolus helmet and a second scan without. Plans were created using both scans. Dose to organs at risk (OAR) including the left optic nerve, right optic nerve, optic chiasm, and normal brain minus CTV (brain-CTV), as well as CTV coverage were compared between the 2 plans. The use of the bolus helmet displayed lower mean OAR doses as well as higher CTV coverage, suggesting that use of the bolus helmet provides benefit when treating the head with IMPT.

UNASSIGNED: To evaluate the dosimetric impact of four different radiotherapy techniques for a case of left-sided breast cancer with Internal Mammary lymph Nodes (IMN) involvement.
UNASSIGNED: To identify the best radiotherapy technique for this patient, four methods were compared: 3D Conformal Radiotherapy (3D-CRT), Volumetric Modulated Arc Therapy (VMAT), Tomotherapy (TOMO) and Intensity Modulated Proton Therapy (IMPT). Patient was treated using deep inspiration breath-hold (DIBH) technique. Prescribed dose was 40.05y in 15 fractions. Plan evaluation was performed on target coverage and dose to the organs-at-risk (OARs) using 3D-CRT as a baseline.
UNASSIGNED: TOMO has the most ideal Conformity Index (CI) at 1.139, followed by IMPT at 1.158, VMAT at 0.765, and 3D-CRT at 0.685. Using 3D-CRT as a baseline, VMAT, TOMO and IMPT all showed improved dose coverage. IMPT has the best dose coverage. TOMO has the most ideal homogeneity index (HI) and Conformity Number (CN). Mean heart dose (MHD) is lowest for IMPT at 0.55 Gy and highest for VMAT at 4.79 Gy. V20Gy of left lung is the lowest for IMPT at 11.11%, compared to 17.53% for TOMO, 18.19% for VMAT and 33.33% for 3D-CRT. V5Gy for the contralateral breast ranges from 0.01% in IMPT to 72.32% in TOMO.
UNASSIGNED: 3D-CRT compromising target coverage but achieving good OAR sparing for the contralateral right breast, left lung and right lung. Overall, IMPT performed best in terms of target coverage and OAR-sparing. Protons delivered superior target dose coverage and sparing of normal structures for this patient. As dose value parameters are expected to correlate with acute and chronic toxicities, proton therapy should be given due consideration as the preferred technique for the treatment of left-sided breast cancers with IMN involvement. Further studies with more patients can be done to evaluate the effectiveness of proton therapy on acute and chronic toxicities.

Adenoid cystic carcinoma (ACC) is generally treated with surgical resection followed by postoperative radiotherapy. In cases where surgical management is precluded due to the location of the tumor and/or patient factors, radiation therapy can be offered to achieve local control. Here, we present a case of unresectable Stage T4N0 ACC of the nasopharynx with skull base and intracranial extension treated with intensity modulated proton therapy (IMPT), which achieved good local control with no significant late toxicity.

To quantify the impact of the degree of robustness against setup errors and range errors on organ-at-risk (OAR) dose and normal tissue complication probabilities (NTCPs) in intensity-modulated proton therapy for oropharyngeal cancer patients.
For 20 oropharyngeal cases (10 unilateral and 10 bilateral), robust treatment plans were generated using \'minimax\' worst-case optimization. We varied the robustness against setup errors (\'setup robustness\') from 1 to 7mm and the robustness against range errors (\'range robustness\') from 1% to 7% (+1mm). We evaluated OAR doses and NTCP-values for xerostomia, dysphagia and larynx edema.
Varying the degree of setup robustness was found to have a considerably larger impact than varying the range robustness. Increasing setup robustness from 1mm to 3, 5, and 7mm resulted in average NTCP-values to increase by 1.9, 4.4 and 7.5 percentage point, whereas they increased by only 0.4, 0.8 and 1.2 percentage point when increasing range robustness from 1% to 3%, 5% and 7%. The degree of setup robustness was observed to have a clinically significant impact in bilateral cases in particular.
For oropharyngeal cancer patients, minimizing setup errors should be given a higher priority than minimizing range errors.

A potential advantage of intensity-modulated proton therapy (IMPT) over intensity-modulated (photon) radiation therapy (IMRT) in the treatment of oropharyngeal carcinoma (OPC) is lower radiation dose to several critical structures involved in the development of nausea and vomiting, mucositis, and dysphagia. The purpose of this study was to quantify doses to critical structures for patients with OPC treated with IMPT and compare those with doses on IMRT plans generated for the same patients and with a matched cohort of patients actually treated with IMRT. In this study, 25 patients newly diagnosed with OPC were treated with IMPT between 2011 and 2012. Comparison IMRT plans were generated for these patients and for additional IMRT-treated controls extracted from a database of patients with OPC treated between 2000 and 2009. Cases were matched based on the following criteria, in order: unilateral vs bilateral therapy, tonsil vs base of tongue primary, T-category, N-category, concurrent chemotherapy, induction chemotherapy, smoking status, sex, and age. Results showed that the mean doses to the anterior and posterior oral cavity, hard palate, larynx, mandible, and esophagus were significantly lower with IMPT than with IMRT comparison plans generated for the same cohort, as were doses to several central nervous system structures involved in the nausea and vomiting response. Similar differences were found when comparing dose to organs at risks (OARs) between the IMPT cohort and the case-matched IMRT cohort. In conclusion, these findings suggest that patients with OPC treated with IMPT may experience fewer and less severe side effects during therapy. This may be the result of decreased beam path toxicities with IMPT due to lower doses to several dysphagia, odynophagia, and nausea and vomiting-associated OARs. Further study is needed to evaluate differences in long-term disease control and chronic toxicity between patients with OPC treated with IMPT in comparison to those treated with IMRT.