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Purpose We present the preliminary results of the STRA-MI-VT Study (NCT04066517), a spontaneous, phase Ib/II study, designed to prospectively test the safety and efficacy of stereotactic body radiotherapy (SBRT) in patientswith advanced cardiac disease and intractable ventricular tachycardia (VT). Methods Cardiac computed tomography (CT) integrated by electroanatomical mapping was used for substrate identification and merged with dedicated CT scans for treatment plan preparation. A single 25-Gy radioablation dose was delivered by a LINAC-based volumetric modulated arc therapy technique in a non-invasive matter. The primary safety endpoint was treatment-related adverse effects during acute and long-term follow-up (FU), obtained by regular in-hospital controls and implantable cardioverter defibrillator (ICD) remote monitoring. The primary efficacy endpoint was the reduction at 3 and 6 months of VT episodes and ICD shocks. Results Seven out of eight patients (men; age, 70 ± 7 years; ejection fraction, 27 ± 11%; 3 ischemic, 4 non-ischemic cardiomyopathies) underwent SBRT. At a median 8-month FU, no treatment-related serious adverse event occurred. Three patients died from non-SBRT-related causes. Four patients completed the 6-month FU: the number of VT decreased from 29 ± 33 to 11 ± 9 (p = .05) and 2 ± 2 (p = .08), at 3 and 6 months, respectively; shocks decreased from 11 to 0 and 2, respectively. At 6 months, all patients. showed a significant reduction of VT episodes and no electrical storm recurrence, with the complete regression of iterative VTs in 2/2 patients. Conclusion The STRA-MI-VT Study suggests that SBRT can be considered an alternative option for the treatment of VT in patients with structural heart disease and highlights the need for further clinical investigation addressing safety and efficacy.

Objective: To compare different stereotactic body techniques—intensity-modulated radiotherapy with photons and protons, applied to radiotherapy of prostatic cancer—with simultaneous integrated boost (SIB) on the dominant intraprostatic lesion (DIL). Methods: Ten patients were selected for this planning study. Dosimetric results were compared between volumetric modulated arc therapy, intensity-modulated radiation therapy (IMRT), and intensity-modulated proton therapy both with two (IMPT 2F) and five fields (IMPT 5F) planning while applying the prescription schemes of 7.25 Gy/fraction to the prostate gland and 7.5 Gy/fraction to the DIL in 5 fractions. Results: Comparison of the coverages of the planning target volumes showed that small differences exist. The IMPT-2F-5F techniques allowed higher doses in the targets; conformal indexes resulted similar; homogeneity was better in the photon techniques (2%–5%). Regarding the organs at risk, all the techniques were able to maintain the dose well below the prescribed constraints: in the rectum, the IMPT-2F-5F and IMRT were more efficient in lowering the intermediate doses; in the bladder, the median dose was significantly better in the case of IMPT (2F–5F). In the urethra, the best sparing was achieved only by IMPT-5F. Conclusions: Stereotactic radiotherapy with SIB for localized prostate cancer is feasible with all the investigated techniques. Concerning IMPT, the two-beam technique does not seem to have a greater advantage compared to the standard techniques; the 5-beam technique seems more promising also accounting for the range uncertainty.

Background Ventricular tachycardia (VT) is a life-threatening condition, which usually implies the need of an implantable cardioverter defibrillator in combination with antiarrhythmic drugs and catheter ablation. Stereotactic body radiotherapy (SBRT) represents a common form of therapy in oncology, which has emerged as a well-tolerated and promising alternative option for the treatment of refractory VT in patients with structural heart disease. Objective In the STRA-MI-VT trial, we will investigate as primary endpoints safety and efficacy of SBRT for the treatment of recurrent VT in patients not eligible for catheter ablation. Secondary aim will be to evaluate SBRT effects on global mortality, changes in heart function, and in the quality of life during follow-up. Methods This is a spontaneous, prospective, experimental (phase Ib/II), open-label study (NCT04066517); 15 patients with structural heart disease and intractable VT will be enrolled within a 2-year period. Advanced multimodal cardiac imaging preceding chest CT-simulation will serve to elaborate the treatment plan on different linear accelerators with target and organs-at-risk definition. SBRT will consist in a single radioablation session of 25 Gy. Follow-up will last up to 12 months. Conclusions We test the hypothesis that SBRT reduces the VT burden in a safe and effective way, leading to an improvement in quality of life and survival. If the results will be favorable, radioablation will turn into a potential alternative option for selected patients with an indication to VT ablation, based on the opportunity to treat ventricular arrhythmogenic substrates in a convenient and less-invasive manner.

CyberKnife® Lung Optimized Treatment (LOT) allows the treatment of lung cancer without invasive fiducial implantation. The aim of this retrospective analysis was to evaluate the feasibility, toxicity and clinical outcome. One hundred fifteen patients (124 lesions) were treated with CyberKnife® using LOT. The median age was 72.6 years (range 31.8-90.3). From 124 treated lesions, 52 were with histopathological confirmation (41 primitive pulmonary cancers, 8 pulmonary metastases) and 72 as untyped tumors. For 5 patients (6 lesions) treatment was an in-field re-irradiation. Concomitant therapy was administered in 7 patients. Zero-View tracking was applied in 69 patients, 1-View in 33 patients, 2-View in 22 patients. The median total dose was 45 Gy (range 18-54), median dose/fraction was 15 Gy (range 4-18) with a median prescription isodose of 80% (range 68-85). The median planning target volume (PTV) was 25 cm3 (range 3-195). The median follow-up was 20 months (range 7-47). Thirty-seven patients (32%) were alive with no evidence of disease, 39 patients (34%) were alive with clinically evident disease, and 38 patients (33%) died of the disease. The 1- and 2-year overall survival (OS) rate was 83% and 61%. The median time to progression was 19 months (95% confidence interval: 11-19 months), 1- and 2-year progression-free survival (PFS) rates were 62% and 41%, respectively. Smaller PTV was significantly associated with better OS, PFS and in-field PFS in univariate and multivariate analyses. Acute toxicity was observed in 36 patients (41%). Late toxicity was registered in 25 patients (29%). G3 late toxicity was observed in one patient (1.1%). Our data suggest that fiducial less-stereotactic body radiation therapy (SBRT) is a feasible, well-tolerated and potentially effective treatment with high compliance in the setting of inoperable patients due to concomitant disease or previous treatments.

The presence of a neobladder constitutes a limitation for the radiation oncologist, as there is no clear evidence about its tolerance to radiotherapy (RT). The limited literature only concerns the conventional postoperative treatment in patients with bladder cancer after cystectomy. Here we report a case of a patient with neobladder who underwent a stereotactic RT for a pelvic recurrence of disease, with response to treatment and no toxicity to the neobladder. This case represents a promising example of the chance to perform RT with ablative intent, using advanced techniques, even on lesions close to the neobladder.

This paper presents a retrospective report on radiotherapy (RT) in the oligometastastic recurrence of bladder cancer. Thirteen patients treated for low-volume metastatic transitional cell urinary bladder carcinoma (TCC) were reviewed, with the primary endpoint to evaluate the safety and efficacy of RT, proposed as an alternative to systemic treatment and/or to defer commencement of systemic therapy. The inclusion criteria were: patients who received RT without other local/systemic therapy for oligometastatic TCC with lymph node, bone and lung lesions or local recurrence. Previous systemic therapy and surgery on the primary tumor were allowed in this tumor response, and toxicity evaluation and progression free-survival was also assessed. Thirteen patients with 21 lesions were treated with stereotactic body radiotherapy (SBRT) or conformal 3D radiotherapy (3D-CRT) between 2012 and 2017. All participants were discussed by a multidisciplinary urological board. The median age at RT was 68 years (range 50-80), the median Karnofsky performance status (KPS) was 90 (range 80-90) and the median interval between TCC diagnosis and commencement of RT on oligometastasis was 23 months (range 8-105). The median treatment dose was 25 Gy (range 20-36 Gy) given over a median of 5 fractions (range 3-10 fractions) with a median follow-up of 25 months (range 3-43 months). Imaging assessment was available for 20 lesions. The radiological progression of disease was registered in 9 patients at the median of 4.2 months from radiotherapy (range 1.9-18.8 months). This identified in-field and out-field progression in 6 patients and only out-field progression in the remaining 3. At last contact, 3 patients were alive with no evidence of disease, 3 had evidence of disease, 6 died of cancer-related disease and one died from another cause. No severe acute and late toxicity was observed. The literature contains no consistent data on TCC oligometastatic setting, but radiotherapy on lymph node, bone and/or lung oligo-recurrence from TCC offers durable disease control in a small number of patients with a very low toxicity profile. Further studies are required to establish the radiotherapy role in oligometastatic recurrent bladder cancer.

The aim is to present the technical feasibility and efficacy of multiple re-irradiation (re-EBRT) for local recurrence of prostate cancer (PCa) using retrospective analysis of an updated series of patients who received ablative re-EBRT with stereotactic image-guided technique for isolated local recurrence of PCa. Eight patients received three RT courses (2 re-RTs); of those 2 received 4 RT courses (3 re-RTs). Local relapse in the prostate was assessed by multiparametric magnetic resonance and/ or choline positron emission tomography. Before treatment planning, all patients had been evaluated for late toxicity from previous RT according to RTOG/EORTC. Biochemical control was assessed according to Phoenix definition. Mean age at the third RT course was 68 (standard deviation, SD: 7.2); all patients had a good performance status. At diagnosis, four cases were classified as high risk PCa, three as intermediate and one as low per NCCN 2017. Biochemical progression free interval after first and second RT-course were 74 (IQR: 59.3-133.6) months and 33 (IQR: 20.8-53.1) months, respectively. Biochemical and radiological response was registered in all patients. At present, seven out of eight patients are disease free. Overall toxicity profile was good; no severe acute or late genitourinary or gastrointestinal events were recorded. Multiple RT courses with high precision technology and image guidance can be proposed as a possible salvage therapy for locally recurrent, low-burden PCa recurrence in adequately selected patients. Deeper understanding of radiobiological effects of hypofractionation and larger series of patients are warranted to fully evaluate the applicability of multiple RT courses in the setting of locally recurrent PCa.

Objectives: To evaluate the feasibility, in terms of acute toxicity and symptom control, of CyberKnife (Accuray, Sunnyvale, CA)-based stereotactic radiotherapy (CyberKnife-SRT) for metastatic orbital lesions. Methods: This retrospective study included patients with symptomatic metastases wholly located within the orbit. Palliative radiation treatment was performed using CyberKnife image-guided technology. Gross tumor volume was defined on a pre-radiotherapy magnetic resonance imaging. Acute and late toxicity was recorded according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer Scale. Results: Between April 2012 and July 2016, 21 patients underwent CyberKnife-SRT for 24 orbital metastases from different primary tumors. Median treatment dose was 18 Gy (15–24 Gy) given in a median of 3 fractions (2–3 fractions) with a median dose of 6 Gy/fraction (5–10 Gy/fraction). Acute grade 1 toxicity was observed in eight cases. No local recurrence occurred after median follow-up of 6.2 months (1.1–30.0 months) among 16 lesions that underwent post-stereotactic radiotherapy magnetic resonance imaging. All patients reported decreasing pre-stereotactic radiotherapy symptoms without late toxicity. Follow-up >6 months (median 22.8 months) was available for nine lesions; complete and partial radiological response was registered in four and five of them, respectively. Conclusion: In our experience, CyberKnife-SRT is a well-tolerated treatment that offers high local and symptom control in patients with intraocular and periocular malignant lesions.

Purpose: To evaluate the geometric and dosimetric accuracies of the CyberKnife Synchrony respiratory tracking system (RTS) and to validate a method for pretreatment patient-specific delivery quality assurance (DQA). Methods: An EasyCube phantom was mounted on the ExacTrac gating phantom, which can move along the superior–inferior (SI) axis of a patient to simulate a moving target. The authors compared dynamic and static measurements. For each case, a Gafchromic EBT3 film was positioned between two slabs of the EasyCube, while a PinPoint ionization chamber was placed in the appropriate space. There were three steps to their evaluation: (1) the field size, the penumbra, and the symmetry of six secondary collimators were measured along the two main orthogonal axes. Dynamic measurements with deliberately simulated errors were also taken. (2) The delivered dose distributions (from step 1) were compared with the planned ones, using the gamma analysis method. The local gamma passing rates were evaluated using three acceptance criteria: 3% local dose difference (LDD)/3 mm, 2%LDD/2 mm, and 3%LDD/1 mm. (3) The DQA plans for six clinical patients were irradiated in different dynamic conditions, to give a total of 19 cases. The measured and planned dose distributions were evaluated with the same gamma-index criteria used in step 2 and the measured chamber doses were compared with the planned mean doses in the sensitive volume of the chamber. Results: (1) A very slight enlargement of the field size and of the penumbra was observed in the SI direction (on average

Introduction Of the different treatments for early prostate cancer, hypofractionated external-beam radiotherapy is one of the most interesting and studied options. Methods The main objective of this phase II clinical study is to evaluate the feasibility, in terms of the incidence of acute side effects, of a new ultra-hypofractionated scheme for low- or intermediate-risk prostate cancer patients treated with the latest imaging and radiotherapy technology, allowing dose escalation to the dominant intraprostatic lesion identified by multiparametric magnetic resonance imaging. Secondary endpoints of the study are the evaluation of the long-term tolerability of the treatment in terms of late side effects, quality of life, and efficacy (oncological outcome). Results The study is ongoing, and we expect to complete recruitment by the end of 2016. Conclusions Like in previous studies, we expect ultra-hypofractionated radiation treatment for prostate cancer to be well tolerated and effective. Trial registration ClinicalTrials.gov identifier: NCT01913717.

To report in-vivo dosimetry in the infraclavicular region, a potential site of a cardiac implantable electronic device (CIED) and to evaluate the absorbed dose from intraoperative radiotherapy with electrons (ELIOT). 27 non-cardiopathic breast cancer (BC) patients without CIED received quadrantectomy and ELIOT as partial breast irradiation. Before delivering ELIOT, two catheters, each containing eight thermoluminescent dosimeters (TLDs), were positioned in the infraclavicular region. TLDs internal catheter was located deep in the tumor bed while the external catheter was placed on patient’s skin. Data were available for 24/27 patients. The absorbed doses were referred to the dose of 21 Gy. Values measured by the external catheter were low, although statistically significant higher doses were found close to the applicator (mean values 0.26–0.49 Gy). External TLD doses in proximity of the applicator were lower than those detected by their internal counterparts. Values measured by the internal catheter TLDs varied according to the distance from the applicator while no correlation with tumor site and beam energy was found. The distance from the applicator to deliver

To evaluate outcome in patients treated with stereotactic body radiotherapy (SBRT) on bone oligometastases from castration-sensitive prostate cancer after primary treatment. We retrospectively collected data of patients with less than five lesions at time of SBRT and hormone-naive disease at the first extra-regional localization, treated between 03/2012 and 11/2016. Prostate-specific antigen (PSA) was measured every 3 months after SBRT. Imaging was performed in case of progression. Survival analysis was performed with Kaplan–Meier (log-rank test) approach. Fifty-five patients were treated on 77 bone oligometastases. Median age, initial PSA and pre-SBRT PSA were 72 years, 9.12 and 3.5 ng/mL, respectively. Twenty-five patients (45%) received SBRT alone while the remaining 30 patients (55%) received concomitant ADT. Median follow-up was 24.6 months (range 3.0–67.2 months). No acute or late toxicity of grade > 1 was reported. Clinical progression was observed in 38 (69%) patients. 1-year biochemical progression-free survival (b-PFS), clinical progression-free survival (c-PFS), prostate-specific survival (PCSS) and local control (LC) rates were 51, 56, 100 and 83%, respectively. Comparing patients treated with SBRT alone and with concomitant ADT, no significant differences were found for those outcomes. SBRT is safe and allows high 1-year LC rate (83%) with low toxicity profile. No significant improvement in outcomes was registered with the addition of ADT to SBRT.

As a result of aging, the number of patients with cardiac implantable electronic device (CIED) requiring radiotherapy (RT) continues to rise. The aim of this work was to evaluate RT-related malfunctions of CIED in a cohort of patients who underwent RT in our clinic from June 2010 to December 2016. We retrospectively analyzed 93 RT treatments in 63 patients with CIEDs. Patients were treated with 3D conformal RT, intensity-modulated RT and stereotactic RT. We collected clinical characteristics of cancer, models of CIEDs, total RT dose to tumor and radiation energy. Radiation dose delivered to CIED and its dysfunctions after RT was evaluated. Subgroup analysis of 48 RT treatments (32 patients) on chest and neck plus on 13 RT treatments (12 patients) with 18 MV neutron-producing photon energy considered as high risk was performed. The number of treatments of patients with CIEDs increased from 0.3% in 2011 to 1.2% in 2016. Two patients, treated with 18 MV photon beam, with implantable cardioverter–defibrillators (ICDs) that received a maximum dose of around 2.1 Gy, experienced adverse events: a reprogramming of ICD when the patient reached a delivered dose to the tumor of 32 Gy, and an altered sensing function requiring replacement after 11 months from the end of RT. Nearly 2% of patients with CIEDs from high-risk patients subgroup had experienced a damage of the device. Close cooperation between radiation oncologists, cardiologists, medical physicists and radiation technologists is needed to achieve the best practice management in these patients.

Background: The aim of this study was to confirm our preliminary results with in vivo dosimetry in non-pregnant breast cancer patients receiving electron beam intraoperative radiotherapy (ELIOT) and to report on the first treatment in a pregnant woman. Patients and Methods: Following our previous experience, 5 non-pregnant patients receiving ELIOT to the tumor bed after breast-conserving surgery (BCS) were studied with thermoluminescent dosimeters positioned in the subdiaphragmatic region, within the uterus, and in the ovarian region. In December 2011, the first pregnant breast cancer patient underwent BCS and ELIOT (21 Gy at 90% isodose) during the 15th week of gestation. Results: The mean dose to the subdiaphragmatic external region in the 5 non-pregnant patients was 5.57 mGy, while pelvic measurements were below 1 mGy. The actual dosimetry of the pregnant patient showed a mean subdiaphragmatic dose of 4.34 mGy, a mean suprapubic dose of 1.64 mGy, and mean ovarian doses of 1.48 mGy (right-sided) and 1.44 mGy (left-sided). The expected dose to the fetus was estimated as 0.84 mGy (0.004% of the prescribed dose). Conclusion: ELIOT as an anticipated boost to the breast could be considered in pregnant women in the early second trimester, postponing whole-breast irradiation after delivery.

Purpose: To report long-term clinical results on breast cancer patients treated with a electron intraoperative boost followed by hypofractionated external beam radiotherapy (HEBRT) to the whole breast inside a clinical protocol. Materials and Methods: Between June 2004 and December 2008, 357 premenopausal women with a diagnosis of early-stage breast cancer were given breast conservative surgery (quadrantectomy and sentinel node biopsy +\- axillary dissection). During surgery, an electron intraoperative boost of 12 Gy was administered to the tumour bed. Within 4 weeks after having received the IORT boost, the whole breast was irradiated with hypofractionated scheme. HEBRT consisted of 13 daily fractions of 2.85 Gy up to a total dose of 37.05 Gy, with 3-D conformal technique. Median age was 42 years (24-48). Pathologic stages were distributed as follow: stage 0 4 (1.1%), I 192(53.8%), stage IIA 108 (30.3%), stage IIB 28 (7.8%), stage IIIA 18 (5%), stage IIIC 6 (1.7%), CR 1(0.3 %). The biomolecular classification included 33 triple negative patients. All patients but one received adjuvant systemic treatment, according to tumor features. Chemotherapy +/- endocrinotherapy was offered to 149 patients, while endocrinotherapy alone was given to 197 patients. In all cases, adjuvant chemotherapy commenced after the completion of HEBRT. Follow-up was carried out on a regular basis by breast surgeons and radiation oncologists. Results: Median follow-up was 83.1 months (range 9.1-118.9). 340 patients were alive and 317 were free of any disease (89%). Three patients (0.8%) had nodal regional recurrence, 12 patients (3.4%) had local recurrence, 26 patients (7.3%) had distant metastasis.13 patients (3.6%) developed contralateral breast cancer.12 patients (3.4%) had a new primary tumor in other site. 15 patients (4.2%) died due to progression of disease, while two died of other causes not related to the breast cancer. Conclusions: This shortened scheme including intraoperative anticipated boost and hypofractionated whole breast radiotherapy showed a good local control at 5 years follow-up. The patients’ compliance is very high and in patients who are in need of chemotherapy, the time gap between surgery and radiotherapy treatment is avoided. As follow-up length increases, a greater number of patients will achieve the minimum 5 -year period to receive the first long-term evaluation and the strength of the results on efficacy is bound to increase. Citation Format: Maria Cristina Leonardi, Anna Morra, Cristiana Fodor, Luigi Santoro, Samantha Dicuonzo, Roberta Lazzari, Veronica Dell'acqua, Elena Rondi, Federica Cattani, Floriana Pansini, Alberto Luini, Roberto Orecchia. Long-term outcome of electron intraoperative boost and hypofractionated external beam radiotherapy after breast-conserving surgery in premenopausal women [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-15-05.

PURPOSE Evaluation of target coverage and verification of safety margins, in motion management strategies implemented by Lung Optimized Treatment (LOT) module in CyberKnife system. METHODS Three fiducial-less motion management strategies provided by LOT can be selected according to tumor visibility in the X ray images acquired during treatment. In 2-view modality the tumor is visible in both X ray images and full motion tracking is performed. In 1-view modality the tumor is visible in a single X ray image, therefore, motion tracking is combined with an internal target volume (ITV)-based margin expansion. In 0-view modality the lesion is not visible, consequently the treatment relies entirely on an ITV-based approach. Data from 30 patients treated in 2-view modality were selected providing information on the three-dimensional tumor motion in correspondence to each X ray image. Treatments in 1-view and 0-view modalities were simulated by processing log files and planning volumes. Planning target volume (PTV) margins were defined according to the tracking modality: end-exhale clinical target volume (CTV) + 3 mm in 2-view and ITV + 5 mm in 0-view. In the 1-view scenario, the ITV encompasses only tumor motion along the non-visible direction. Then, non-uniform ITV to PTV margins were applied: 3 mm and 5 mm in the visible and non-visible direction, respectively. We defined the coverage of each voxel of the CTV as the percentage of X ray images where such voxel was included in the PTV. In 2-view modality coverage was calculated as the intersection between the CTV centred on the imaged target position and the PTV centred on the predicted target position, as recorded in log files. In 1-view modality, coverage was calculated as the intersection between the CTV centred on the imaged target position and the PTV centred on the projected predictor data. In 0-view modality coverage was calculated as the intersection between the CTV centred on the imaged target position and the non-moving PTV. Similar to dose-volume histogram, CTV coverage-volume histograms (defined as CVH) were derived for each patient and treatment modality. The geometric coverages of the 90% and 95% of CTV volume (C90, C95, respectively) were evaluated. Patient-specific optimal margins (ensuring C95 ≥ 95%) were computed retrospectively. RESULTS The median ± interquartile-rage of C90 and C95 for upper lobe lesions was 99.1 ± 0.6% and 99.0 ± 3.1%, whereas they were 98.9 ± 4.2% and 97.8 ± 7.5% for lower and middle lobe tumors. In 2-view, 1-view and 0-view modality, adopted margins ensured C95 ≥ 95% in 70%, 85% and 63% of cases and C95 ≥ 90% in 90%, 88% and 83% of cases, respectively. In 2-view, 1-view and 0-view a reduction in margins still ensured C95 ≥ 95% in 33%, 78% and 59% of cases, respectively. CONCLUSIONS CTV coverage analysis provided an a-posteriori evaluation of the treatment geometric accuracy and allowed a quantitative verification of the adequacy of the PTV margins applied in CyberKnife LOT treatments offering guidance in the selection of CTV margins.

The integration of CT and multiparametric MRI (mpMRI) is a challenging task in high-precision radiotherapy for prostate cancer. A simple methodology for multimodal deformable image registration (DIR) of prostate cancer patients is presented.CT and mpMRI of 10 patients were considered. Organs at risk and prostate were contoured on both scans. The dominant intraprostatic lesion was additionally delineated on MRI. After a preliminary rigid image registration, the voxel intensity of all the segmented structures in both scans except the prostate was increased by a specific amount (a constant additional value, A), in order to enhance the contrast of the main organs influencing its position and shape. 70 couples of scans were obtained by varying A from 0 to 800 and they were subsequently non-rigidly registered. Quantities derived from image analysis and contour statistics were considered for the tuning of the best performing A.A = 200 resulted the minimum enhancement value required to obtain statistically significant superior registration results. Mean centre of mass distance between corresponding structures decreases from 7.4 mm in rigid registration to 5.3 mm in DIR without enhancement (DIR-0) and to 2.7 mm in DIR with A = 200 (DIR-200). Mean contour distance was 2.5, 1.9 and 0.67 mm in rigid registration, DIR-0 and DIR-200, respectively. In DIR-200 mean contours overlap increases of +13 and +24% with respect to DIR-0 and rigid registration, respectively.Contour propagation according to the vector field resulting from DIR-200 allows the delineation of dominant intraprostatic lesion on CT scan and its use for high-precision radiotherapy treatment planning. Advances in knowledge: We investigated the application of a B-spline, mutual information-based multimodal DIR coupled with a simple, patient-unspecific but efficient contrast enhancement procedure in the pelvic body area, thus obtaining a robust and accurate methodology to transfer the functional information deriving from mpMRI onto a planning CT reference volume.

Background The purpose of the study was to evaluate the prostate serum antigen (PSA) response, local control, progression-free survival (PFS), and toxicity of stereotactic body radiotherapy (SBRT) for lymph node (LN) oligorecurrent prostate cancer. Patients and Methods Between May 2012 and October 2015, 124 lesions were treated in 94 patients with a median dose of 24 Gy in 3 fractions. Seventy patients were treated for a single lesion and 25 for > 1 lesion. In 34 patients androgen deprivation (AD) was combined with SBRT. We evaluated biochemical response according to PSA level every 3 months after SBRT: a 3-month PSA decrease from pre-SBRT PSA of more than 10% identified responder patients. In case of PSA level increase, imaging was performed to evaluate clinical progression. Toxicity was assessed every 6 to 9 months after SBRT. Results Median follow-up was 18.5 months. In 13 patients (14%) Grade 1 to 2 toxicity was reported without any Grade 3 to 4 toxicity. Biochemical response, stabilization, and progression were observed in 64 (68%), 10 (11%), and 20 (21%) of 94 evaluable patients. Clinical progression was observed in 31 patients (33%) after a median time of 8.1 months. In-field progression occurred in 12 lesions (9.7%). Two-year local control and PFS rates were 84% and 30%, respectively. Age older than 75 years correlated with better biochemical response rate. Age older than 75 years, concomitant AD administered up to 12 months, and pelvic LN involvement correlated with longer PFS. Conclusion SBRT is safe and offers good in-field control. At 2 years after SBRT, 1 of 3 patients is progression-free. Further investigation is warranted to identify patients who benefit most from SBRT and to define the optimal combination with AD.

OBJECTIVE: To evaluate high-precision external beam reirradiation (re-EBRT) for local relapse of prostate cancer (PCa) after radiotherapy. METHODS: This retrospective study included patients with biochemical failure and evidence of isolated local recurrence of PCa after radical/salvage EBRT or brachytherapy that received salvage stereotactic body radiation therapy (SBRT, re-EBRT). Biopsy was not mandatory if all diagnostic elements were univocal (prostate specific antigen evolution, choline-positron emission tomography or magnetic resonance imaging). Salvage SBRT (re-EBRT) was delivered with image-guided radiation therapy (RapidArc®, VERO® and CyberKnife®). RESULTS: Data of 64 patients were included, median age at salvage SBRT was 73.2 years, median pre-salvage SBRT prostate specific antigen was 3.89 ng ml(−1) . Median total dose was 30 Gy in five fractions, biologically effective dose (BED) of 150 Gy. One acute G3 genitourinary event and one late G3 genitourinary event were observed. No G ≥ 3 bowel toxicity was registered. At the median follow-up of 26.1 months, tumor progression was observed in 41 patients (64%). 18 patients (28%) experienced local relapse. 2-year local control, biochemical and clinical relapse free survival rates were 75, 40 and 53%, respectively. With BED ≥130 Gy 1-year biochemical and clinical progression-free survival rate were 85 and 90%, respectively. CONCLUSIONS: Salvage SBRT (re-EBRT) for isolated local PCa recurrence is a safe, feasible and noninvasive salvage treatment. Further investigation is warranted to define the optimal patient selection, dose and volume parameters. ADVANCES IN KNOWLEDGE: Salvage SBRT reirradiation for the locally recurrent PCa offer a satisfactory tumor control and excellent toxicity profile, if BED ≥130 Gy is administered.

In women with large and pendulous breasts postoperative radiotherapy in the supine position could represent a technical challenge because of the resulting dose inhomogeneity and the large amount of lung and heart receiving a high percentage of the prescribed dose. Breast-conserving surgery is therefore relatively contraindicated in these patients. Alternative positions for radiation therapy treatment have been proposed, and prone breast irradiation in particular has been recognized as a useful alternative to conventional treatment in the supine position. We report the case of a large-breasted patient treated in prone position in our radiation therapy division.

Purpose: To evaluate the incidence of thyroid disorders and dose distribution to the thyroid in patients treated with radiotherapy for head-and-neck carcinomas. Methods and Materials: A retrospective evaluation of data from 73 patients treated for head-and-neck cancers in our department was performed. Thyroid function was evaluated mainly by the measurement of thyrotropin (thyroid stimulating hormone [TSH]). A retrospective analysis of treatment plans was performed for 57 patients. Percentages of thyroid glandular volume absorbing 10, 30, and 50 Gy (V10, V30, and V50 respectively) were considered for statistical analysis. Results: A majority of patients (61%) had a normal thyroid function whereas 19 patients (26%) had hypothyroidism. Mean thyroid volume was 30.39 cc. Point 3 (located at isthmus) absorbed lower doses compared with other points (p< 0.0001). Median values of V10, V30, and V50 were 92% (range, 57–100%), 75% (range, 28.5–100%), and 35% (range, 3– 83%) respectively. Gender was associated with toxicity (presence of any kind of thyroid disorders) (p < 0.05), with females displaying higher levels of TSHr (relative TSH patient’s value/maximum value of the laboratory range) (p 0.0005) and smaller thyroid volume (p 0.0012) compared with male population. TSHr values were associated with thyroid volume, and the presence of midline shielding block in the anterior field was associated with relative free thyroxine (FT4r patient’s value/maximum value of the laboratory range) values. Conclusions: Gender and thyroid volume seem to play an important role in the occurrence of thyroid toxicity, but further studies on dose– effect relationship for radiotherapy-induced thyroid toxicity are needed. © 2007 Elsevier Inc. Thyroid disorders, Radiotherapy, Cancer.

To compare the patient set-up error detection capabilities of three-dimensional cone beam computed tomography (3D-CBCT) and two-dimensional orthogonal kilovoltage (2D-kV) techniques.3D-CBCT and 2D-kV projections were acquired on 29 head-and-neck (HN) patients undergoing Intensity Modulated Radiotherapy (IMRT) on the first day of treatment (time 0) and after the delivery of 40 Gy and 50 Gy. Set-up correction vectors were analyzed after fully automatic image registration as well as after revision by radiation oncologists. The dosimetric effects of the different sensitivities of the two image guidance techniques were assessed.A statistically significant correlation among detected set-up deviations by the two techniques was found along anatomical axes (0.60 ρ 0.72, p 0.0001); no correlation was found for table rotation (p = 0.41). No evidence of statistically significant differences between the indications provided along the course of the treatment was found; this was also the case when full automatic versus manually refined correction vectors were compared. The dosimetric effects analysis revealed slight statistically significant differences in the median values of the maximum relative dose to mandible, spinal cord and its 5 mm Planning Organ at Risk Volume (0.95%, 0.6% and 2.45%, respectively), with higher values (p 0.01) observed when 2D-kV corrections were applied.A similar sensitivity to linear set-up errors was observed for 2D-kV and 3D-CBCT image guidance techniques in our HN patient cohort. Higher rotational deviations around the table vertical axis were detected by the 3D-CBCT with respect to the 2D-kV method, leading to a consistent better sparing of organs at risk.

Background and purpose Limited information is available on the true radiation exposure and associated risks for the relatives of the patients submitted to prostate brachytherapy with permanent implant of radioactive sources and for any other people coming into contact with them. In order to provide appropriate information, we analyzed the radiation exposure data from 216 prostate cancer patients who underwent 125 I or 103 Pd implants at the European Institute of Oncology of Milan, Italy. Patients and methods Between October 1999 and October 2004, 216 patients with low risk prostate carcinoma were treated with 125 I (200 patients) or 103 Pd (16 patients) permanent seed implantation. One day after the procedure, radiation exposure measurements around the patients were performed using an ionization chamber survey meter (Victoreen RPO-50) calibrated in dose rate at an accredited calibration center (calibration Centre SIT 104). Results The mean dose rate at the posterior skin surface (gluteal region) following 125 I implants was 41.3μSv/h (range: 6.2–99.4μSv/h) and following 103 Pd implants was 18.9μSv/h (range 5.0–37.3μSv/h). The dose rate at 50cm from the skin decreased to the mean value of 6.4μSv/h for the 125 I implants and to the mean value of 1.7μSv/h for the 103 Pd implants. Total times required to reach the annual dose limit (1mSv/year) recommended for the general population by the European Directive 96/29/Euratom and by the Italian law (Decreto Legislativo 241/2000) at a distance of 50cm from the posterior skin surface of the implanted patient would be 7.7 and 21.6 days for 125 I and for 103 Pd. Good correlation between the measured dose rates and both the total implanted activity and the distance between the most posteriorly implanted seed and the skin surface of the patients was found. Conclusions Our data show that the dose rates at 50cm away from the prostate brachytherapy patients are very low and that the doses possibly absorbed by the relatives and other members of the general population coming into contact with the treated patients are well below the dose limit set by the European Directive and by the Italian regulation. However, in order to meet the recommendation of the ALARA principle (As Low As Reasonably/Readily Achievable), some advice to the patients should be given, such as to maintain a minimum distance from the patient of 1m, at least for a period equal to one half life of used radionuclide (60 days for 125 I and 15 days for 103 Pd).

Recent data show that axillary coverage can be obtained, but only through a selective CT-based treatment planning, as standard tangential fields are inadequate to deliver therapeutic doses. Currently, the replacement of axillary dissection with new techniques, such as sentinel node (SN) biopsy, makes it necessary to re-address the question about the real role of axillary irradiation, complicated by the differences in the anatomy of dissected and undissected axillary regions. The purpose of this paper is the dosimetric analysis of first axillary level coverage in standard irradiation of 15 breast-cancer patients treated with quadrantectomy and SN biopsy (negative finding). During surgery a clip on the site of the SN was positioned, marking the caudal margin of first axillary level. After the breast treatment plan was completed, the first axillary level was contoured on CT scans, from the site of the surgical clip up to the sternal manubrium, for coverage analysis with dose-volume histograms (DVHs) and three-dimensional isodose visualization. The maximum dose mean ranged from 5% to 80% of the prescribed dose (mean value 48.7%). The mean total dose received by the volume of interest was lower than 40 Gy in all but one patient. No patient had total irradiation of first nodal level; only one patient had 35% of the volume enclosed in the 100% isodose. Our analysis lead to the conclusion that therapeutic doses are not really delivered to first level axillary level nodes by a standard tangential field technique, and that specific treatment planning and beam arrangement are required when adequate coverage is necessary.

Background and purpose : To check the dose delivered to patients during intraoperative electron beam radiation therapy (IOERT) for early breast cancer and also to define appropriate action levels. Patients and methods : Between December 2000 and June 2001, 54 patients affected by early-stage breast cancer underwent exclusive IOERT to the tumour bed using a Novac7 mobile linac, after quadrantectomy. Electron beams (5, 7, 9MeV) at high dose per pulse values (0.02–0.09Gy/pulse) were used. The prescribed single dose was 21Gy at the depth of 90% isodose (14–22 mm). In 35 cases, in vivo dosimetry was performed. The entrance dose was derived from the surface dose measured with thin and calibrated MD-55-2 radiochromic films, wrapped in sterile envelopes. Films were analysed 24–72 h after the irradiation using a charge-coupled-device imaging system. Field disturbance caused by the film envelope was negligible. Results : The mean deviation between measured and expected doses was 1.8%, with one SD equal to 4.7%. Deviations larger than 7% were found in 23% of cases, never consecutively, not correlated with beam energy or field size and with no evidence of linac daily output variation or serious malfunctioning or human mistake. The estimated overall uncertainty of dose measurement was about 4%. In vivo dosimetry appeared both reliable and feasible. Two action levels, for unexplained observed deviations larger than 7 and 10%, were preliminary defined. Conclusions : Satisfactory agreement between measured and expected doses was found. The implementation of in vivo dosimetry in IOERT is suggested, particularly for patients enrolled in a clinical trial.

To analyze dose distribution in the hearing organ and to evaluate the dose effect on the hearing thresholds in patients treated with post-parotidectomy 3-dimensional conformal radiotherapy (3D-CRT). A total of 17 patients received post-parotidectomy 3D-CRT (median dose: 63 Gy). The audiometric evaluation comprised pure tone audiometry and tympanometry performed before radiotherapy (RT) and 3, 6, and 24 months after RT. The ear structures were delineated on planning computer tomography scans. Mean and maximum doses were calculated and dose–volume histograms were plotted. Before RT, the median baseline audiometric thresholds were normal. At 3 months post-RT, 3 patients were diagnosed as having middle ear underpressure and/or effusion that resolved completely by 6 months. During 2-year follow-up, none of the ears showed perceptive hearing loss at speech frequencies. The mean doses at ipsilateral external auditory canal, mastoids cells, tympanic case, Eustachian tube, semicircular canals, and cochlea were 44.8 Gy, 39.0 Gy, 30.9 Gy, 33.0 Gy, 19.6 Gy, and 19.2 Gy, respectively. The doses to the contralateral ear were negligible, except for the Eustachian tube (up to 28.2 Gy). Post-parotidectomy 3D-CRT is associated with relatively low doses to the ear and the surrounding structures. Post-RT audiometry did not show any permanent (neither conductive nor perceptive) hearing impairment. Only in 3 patients were there signs of transient unilateral dysfunction of the Eustachian tube observed during the first few months after RT. Longer follow-up and larger patient series are warranted to confirm these preliminary findings.