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Schwarz M.,Agenzia Provinciale per la Protonterapia
European Physical Journal Plus

Radiotherapy treatment planning is a procedure that, using radiation beam and patient's anatomy models as input data, produces as output the machine instructions to deliver the treatment and the expected dose distribution in the patient. Now that most proton therapy centers are moving from double scattered proton beams to active delivery systems such as pencil beam scanning (PBS), there is a need for treatment planning tools that could generate safe and effective dose distribution by taking full benefit of the potential of PBS degrees of freedom, and by avoiding the risks associated to this modality. The paper provides an overview of the current status of proton treatment planning techniques, from the creation of a patient model via imaging, to dose calculation, to the optimization of plans using intensity modulated proton therapy (IMPT). The issue of plan sensitivity to input data ("plan robustness") is emphasized and current approaches to robust optimization are presented. Finally, current developments in "adaptive planning" and in the plan design for moving organs are shortly discussed. © Società Italiana di Fisica/Springer-Verlag 2011. Source

Rancati T.,Fondazione Istituto Nazionale Dei Tumori | Schwarz M.,Agenzia Provinciale per la Protonterapia | Allen A.M.,Rabin Medical Center | Feng F.,University of Michigan | And 3 more authors.
International Journal of Radiation Oncology Biology Physics

The dose-volume outcome data for RT-associated laryngeal edema, laryngeal dysfunction, and dysphagia, have only recently been addressed, and are summarized. For late dysphagia, a major issue is accurate definition and uncertainty of the relevant anatomical structures. These and other issues are discussed. © 2010 Elsevier Inc. All rights reserved. Source

Fellin F.,Agenzia Provinciale per la Protonterapia | Azzeroni R.,San Raffaele Scientific Institute | Maggio A.,San Raffaele Scientific Institute | Lorentini S.,Agenzia Provinciale per la Protonterapia | And 5 more authors.
Radiotherapy and Oncology

Purpose To compare helical tomotherapy (HT) and intensity modulated proton therapy (IMPT) for prostate cancer irradiation while concomitantly boosting dominant intraprostatic lesions (DILs). Methods and materials Treatment plans of seven patients were designed for HT and IMPT (pencil beam size: 3 mm sigma). The prescribed median PTV/DIL doses were 71.4/100 Gy in 28 fractions, while satisfying "safe" dose constraints for organs at risks (OARs) including rectum, bladder, femoral heads, penile bulb and urethra. The planner could further reduce the dose to OARs if PTV/DIL constraints were reached. Results IMPT achieved better dose conformity (CI = 1.11 vs 1.31, p < 0.05) and coverage (V95% = 97.3% vs 95.3%, p < 0.05) in PTV. Concerning DIL volumes, both techniques delivered the prescribed dose (Dmedian: HT = 100 Gy, IMPT = 102.1 Gy) with similar dose conformity (CI: HT = 1.49, IMPT = 1.44) and same dose homogeneity, D99%, D1%, while satisfying the OARs constraints. Excepting urethra, the sparing of OARs was significantly better with IMPT; in general, the lower the dose, the greater the benefit of IMPT. Normal tissue complication probabilities for the rectum were in favor of IMPT with an absolute reduction of 3-8%, depending on the NTCP model (p < 0.05). Conclusions Both techniques allowed delivering 100 Gy to DILs, while complying with the OARs constraints. IMPT was superior in sparing OARs for doses up to approximately 70 Gy, with larger benefit at lower doses. © 2013 Elsevier Ireland Ltd. All rights reserved. Source

La Macchia M.,Agenzia Provinciale per la Protonterapia | Fellin F.,Agenzia Provinciale per la Protonterapia | Amichetti M.,Agenzia Provinciale per la Protonterapia | Cianchetti M.,Agenzia Provinciale per la Protonterapia | And 6 more authors.
Radiation Oncology

Purpose: To validate, in the context of adaptive radiotherapy, three commercial software solutions for atlas-based segmentation.Methods and materials: Fifteen patients, five for each group, with cancer of the Head&Neck, pleura, and prostate were enrolled in the study. In addition to the treatment planning CT (pCT) images, one replanning CT (rCT) image set was acquired for each patient during the RT course. Three experienced physicians outlined on the pCT and rCT all the volumes of interest (VOIs). We used three software solutions (VelocityAI 2.6.2 (V), MIM 5.1.1 (M) by MIMVista and ABAS 2.0 (A) by CMS-Elekta) to generate the automatic contouring on the repeated CT. All the VOIs obtained with automatic contouring (AC) were successively corrected manually. We recorded the time needed for: 1) ex novo ROIs definition on rCT; 2) generation of AC by the three software solutions; 3) manual correction of AC.To compare the quality of the volumes obtained automatically by the software and manually corrected with those drawn from scratch on rCT, we used the following indexes: overlap coefficient (DICE), sensitivity, inclusiveness index, difference in volume, and displacement differences on three axes (x, y, z) from the isocenter.Results: The time saved by the three software solutions for all the sites, compared to the manual contouring from scratch, is statistically significant and similar for all the three software solutions. The time saved for each site are as follows: about an hour for Head&Neck, about 40 minutes for prostate, and about 20 minutes for mesothelioma. The best DICE similarity coefficient index was obtained with the manual correction for: A (contours for prostate), A and M (contours for H&N), and M (contours for mesothelioma).Conclusions: From a clinical point of view, the automated contouring workflow was shown to be significantly shorter than the manual contouring process, even though manual correction of the VOIs is always needed. © 2012 La Macchia et al.; licensee BioMed Central Ltd. Source

Schwarz M.,Agenzia Provinciale per la Protonterapia | Pierelli A.,Istituto Scientifico S. Raffaele | Fiorino C.,Istituto Scientifico S. Raffaele | Fellin F.,Agenzia Provinciale per la Protonterapia | And 5 more authors.
Radiotherapy and Oncology

Purpose: To compare helical tomotherapy (HT) and intensity modulated proton therapy (IMPT) on early stage prostate cancer treatments delivered with simultaneous integrated boost (SIB) in moderate hypofractionation. Material/methods: Eight patients treated with HT were replanned with two-field IMPT (2fIMPT) and five-field IMPT (5fIMPT), using a small pencil beam size (3 mm sigma). The prescribed dose was 74.3 Gy in 28 fractions on PTV1 (prostate) and PTV2 (proximal seminal vesicles), 65.5 Gy on PTV3 (distal seminal vesicles) and on the overlap between rectum and PTVs. Results: IMPT and HT achieved similar target coverage and dose homogeneity, with 5fIMPT providing the best results. The conformity indexes of IMPT were significantly lower for PTV1+2 and PTV3. Above 65 Gy, HT and IMPT were equivalent in the rectum, while IMPT spared the bladder and the penile bulb from 0 to 70 Gy. From 0 up to 60 Gy, IMPT dosimetric values were (much) lower for all OARs except the femur heads, where HT was better than 2fIMPT in the 25-35 Gy dose range. OARs mean doses were typically reduced by 30-50% by IMPT. NTCPs for the rectum were within 1% between the two techniques, except when the endpoint was stool frequency, where IMPT showed a small (though statistically significant) benefit. Conclusions: HT and IMPT produce similar dose distributions in the target volume. The current knowledge on dose-effect relations does not allow to quantify the clinical impact of the large sparing of IMPT at medium-to-low doses. © 2010 Elsevier Ireland Ltd. All rights reserved. Source

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