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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 | Year: 2013

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.


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 | Year: 2012

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.


Rancati T.,Fondazione IRCCS Instituto 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 | Year: 2010

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.


Cantone M.C.,University of Milan | Ciocca M.,Centro Nazionale Of Adroterapia Oncologica Cnao Foundation | Dionisi F.,Agenzia Provinciale per la Protonterapia | Fossati P.,Centro Nazionale Of Adroterapia Oncologica Cnao Foundation | And 10 more authors.
Radiation Oncology | Year: 2013

Background: A multidisciplinary and multi-institutional working group applied the Failure Mode and Effects Analysis (FMEA) approach to the actively scanned proton beam radiotherapy process implemented at CNAO (Centro Nazionale di Adroterapia Oncologica), aiming at preventing accidental exposures to the patient. Methods: FMEA was applied to the treatment planning stage and consisted of three steps: i) identification of the involved sub-processes; ii) identification and ranking of the potential failure modes, together with their causes and effects, using the risk probability number (RPN) scoring system, iii) identification of additional safety measures to be proposed for process quality and safety improvement. RPN upper threshold for little concern of risk was set at 125.Results: Thirty-four sub-processes were identified, twenty-two of them were judged to be potentially prone to one or more failure modes. A total of forty-four failure modes were recognized, 52% of them characterized by an RPN score equal to 80 or higher. The threshold of 125 for RPN was exceeded in five cases only. The most critical sub-process appeared related to the delineation and correction of artefacts in planning CT data. Failures associated to that sub-process were inaccurate delineation of the artefacts and incorrect proton stopping power assignment to body regions. Other significant failure modes consisted of an outdated representation of the patient anatomy, an improper selection of beam direction and of the physical beam model or dose calculation grid. The main effects of these failures were represented by wrong dose distribution (i.e. deviating from the planned one) delivered to the patient. Additional strategies for risk mitigation, easily and immediately applicable, consisted of a systematic information collection about any known implanted prosthesis directly from each patient and enforcing a short interval time between CT scan and treatment start. Moreover, (i) the investigation of dedicated CT image reconstruction algorithms, (ii) further evaluation of treatment plan robustness and (iii) implementation of independent methods for dose calculation (such as Monte Carlo simulations) may represent novel solutions to increase patient safety.Conclusions: FMEA is a useful tool for prospective evaluation of patient safety in proton beam radiotherapy. The application of this method to the treatment planning stage lead to identify strategies for risk mitigation in addition to the safety measures already adopted in clinical practice. © 2013 Cantone et al.; licensee BioMed Central Ltd.


Lorentini S.,Agenzia Provinciale per la Protonterapia | Amelio D.,Agenzia Provinciale per la Protonterapia | Giri M.G.,Azienda Ospedaliera Universitaria Integrata of Verona | Fellin F.,Agenzia Provinciale per la Protonterapia | And 4 more authors.
Technology in Cancer Research and Treatment | Year: 2013

Intensity modulated radiation therapy (IMRT) is increasingly employed in glioblastoma (GBM) treatment. The present work aimed to assess which clinical-dosimetric scenario could benefit the most from IMRT application, with respect to three-dimensional conformal radiation therapy (3D-CRT). The number of organs at risk (OARs) overlapping the planning target volume (PTV) was the parameter describing the clinical-dosimetric pattern. Based on the results, a dosimetric decision criterion to select the most appropriate treatment technique is provided. Seventeen previously irradiated patients were retrieved and re-planned with both 3D-CRT and IMRT. The prescribed dose was 60 Gy/30fx. The cases were divided into 4 groups (4 patients in each group). Each group represents the scenario where 0, 1, 2 or 3 OARs overlapped the target volume, respectively. Furthermore, in one case, 4 OARs overlapped the PTV. The techniques were compared also in terms of irradiated healthy brain tissue. The results were evaluated by paired t-test. IMRT always provided better target coverage (V95%) than 3D-CRT, regardless the clinical-dosimetric scenario: difference ranged from 0.82% (p = 0.4) for scenario 0 to 7.8% (p = 0.02) for scenario 3, passing through 2.54% (p = 0.18) and 5.93% (p = 0.08) for scenario 1 and 2, respectively. IMRT and 3D-CRT achieved comparable results in terms of dose homogeneity and conformity. Concerning the irradiation of serial-kind OARs, both techniques provided nearly identical results. A statistically significant dose reduction to the healthy brain in favor of IMRT was scored. IMRT seems a superior technique compared to 3D-CRT when there are multiple overlaps between OAR and PTV. In this scenario, IMRT allows for a better target coverage while maintaining equivalent OARs sparing and reducing healthy brain irradiation. The results from our patients dataset suggests that the overlap of three OARs can be used as a dosimetric criterion to select which patients should receive IMRT treatment. © Adenine Press (2013).


Schwarz M.,Agenzia Provinciale per la Protonterapia | Pierelli A.,Instituto Scientifico S Raffaele | Fiorino C.,Instituto Scientifico S Raffaele | Fellin F.,Agenzia Provinciale per la Protonterapia | And 5 more authors.
Radiotherapy and Oncology | Year: 2011

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.


Schwarz M.,Agenzia Provinciale per la Protonterapia
European Physical Journal Plus | Year: 2011

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.


PubMed | Agenzia Provinciale per la Protonterapia
Type: Journal Article | Journal: Medical physics | Year: 2012

To assess the quality of dose distributions in real clinical cases for different dimensions of scanned proton pencil beams. The distance between spots (i.e., the grid of delivery) is optimized for each dimension of the pencil beam.The authors vary the of the initial Gaussian size of the spot, from (x)=(y)=3 mm to (x)=(y)=8 mm, to evaluate the impact of the proton beam size on the quality of intensity modulated proton therapy (IMPT) plans. The distance between spots, x and y, is optimized on the spot plane, ranging from 4 to 12 mm (i.e., each spot size is coupled with the best spot grid resolution). In our Hyperion treatment planning system (TPS), constrained optimization is applied with respect to the organs at risk (OARs), i.e., the optimization tries to satisfy the dose objectives in the planning target volume (PTV) as long as all planning objectives for the OARs are met. Three-field plans for a nasopharynx case, two-field plans for a prostate case, and two-field plans for a malignant pleural mesothelioma case are considered in our analysis.For the head and neck tumor, the best grids (i.e., distance between spots) are 5, 4, 6, 6, and 8 mm for =3, 4, 5, 6, and 8 mm, respectively. 5 mm is required for tumor volumes with low dose and 4mm for tumor volumes with high dose. For the prostate patient, the best grid is 4, 4, 5, 5, and 5 mm for =3, 4, 5, 6, and 8 mm, respectively. Beams with >3 mm did not satisfy our first clinical requirement that 95% of the prescribed dose is delivered to more than 95% of prostate and proximal seminal vesicles PTV. Our second clinical requirement, to cover the distal seminal vesicles PTV, is satisfied for beams as wide as =6 mm. For the mesothelioma case, the low dose PTV prescription is well respected for all values of , while there is loss of high dose PTV coverage for >5 mm. The best grids have a spacing of 6, 7, 8, 9, and 12 mm for =3, 4, 5, 6, and 8 mm, respectively.The maximum acceptable proton pencil beam depends on the volume treated, the protocol of delivery, and optimization of the plan. For the clinical cases, protocol and optimization used in this analysis, acceptable s are 4mm for the head and neck tumor, 3mm for the prostate tumor and 6mm for the malignant pleural mesothelioma. One can apply the same procedure used in this analysis when given a class of patients, a and a clinical protocol to determine the optimal grid spacing.


PubMed | Agenzia Provinciale per la Protonterapia
Type: Comparative Study | Journal: Technology in cancer research & treatment | Year: 2013

Intensity modulated radiation therapy (IMRT) is increasingly employed in glioblastoma (GBM) treatment. The present work aimed to assess which clinical-dosimetric scenario could benefit the most from IMRT application, with respect to three-dimensional conformal radiation therapy (3D-CRT). The number of organs at risk (OARs) overlapping the planning target volume (PTV) was the parameter describing the clinical-dosimetric pattern. Based on the results, a dosimetric decision criterion to select the most appropriate treatment technique is provided. Seventeen previously irradiated patients were retrieved and re-planned with both 3D-CRT and IMRT. The prescribed dose was 60 Gy/30fx. The cases were divided into 4 groups (4 patients in each group). Each group represents the scenario where 0, 1, 2 or 3 OARs overlapped the target volume, respectively. Furthermore, in one case, 4 OARs overlapped the PTV. The techniques were compared also in terms of irradiated healthy brain tissue. The results were evaluated by paired t-test. IMRT always provided better target coverage (V95%) than 3D-CRT, regardless the clinical-dosimetric scenario: difference ranged from 0.82% (p = 0.4) for scenario 0 to 7.8% (p = 0.02) for scenario 3, passing through 2.54% (p = 0.18) and 5.93% (p = 0.08) for scenario 1 and 2, respectively. IMRT and 3D-CRT achieved comparable results in terms of dose homogeneity and conformity. Concerning the irradiation of serial-kind OARs, both techniques provided nearly identical results. A statistically significant dose reduction to the healthy brain in favor of IMRT was scored. IMRT seems a superior technique compared to 3D-CRT when there are multiple overlaps between OAR and PTV. In this scenario, IMRT allows for a better target coverage while maintaining equivalent OARs sparing and reducing healthy brain irradiation. The results from our patients dataset suggests that the overlap of three OARs can be used as a dosimetric criterion to select which patients should receive IMRT treatment.

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