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Purpose Risk classification of primary prostate cancer in clinical routine is mainly based on prostate-specific antigen (PSA) levels, Gleason scores from biopsy samples, and tumor-nodes-metastasis (TNM) staging. This study aimed to investigate the diagnostic performance of positron emission tomography/magnetic resonance imaging (PET/MRI) in vivo models for predicting low-vs-high lesion risk (LH) as well as biochemical recurrence (BCR) and overall patient risk (OPR) with machine learning. Methods Fifty-two patients who underwent multi-parametric dual-tracer [18F]FMC and [68Ga]Ga-PSMA-11 PET/MRI as well as radical prostatectomy between 2014 and 2015 were included as part of a single-center pilot to a randomized prospective trial (NCT02659527). Radiomics in combination with ensemble machine learning was applied including the [68Ga]Ga-PSMA-11 PET, the apparent diffusion coefficient, and the transverse relaxation time-weighted MRI scans of each patient to establish a low-vs-high risk lesion prediction model (MLH). Furthermore, MBCR and MOPR predictive model schemes were built by combining MLH, PSA, and clinical stage values of patients. Performance evaluation of the established models was performed with 1000-fold Monte Carlo (MC) cross-validation. Results were additionally compared to conventional [68Ga]Ga-PSMA-11 standardized uptake value (SUV) analyses. Results The area under the receiver operator characteristic curve (AUC) of the MLH model (0.86) was higher than the AUC of the [68Ga]Ga-PSMA-11 SUVmax analysis (0.80). MC cross-validation revealed 89% and 91% accuracies with 0.90 and 0.94 AUCs for the MBCR and MOPR models respectively, while standard routine analysis based on PSA, biopsy Gleason score, and TNM staging resulted in 69% and 70% accuracies to predict BCR and OPR respectively. Conclusion Our results demonstrate the potential to enhance risk classification in primary prostate cancer patients built on PET/MRI radiomics and machine learning without biopsy sampling.

A 36-year-old Mexican female with a slowly growing foot mass was referred to orthopedic surgery clinic for further evaluation. Foot magnetic resonance imaging revealed an infiltrative soft tissue mass along the dorsal aspect of the fourth metatarsal. T2-weighted images revealed multiple central low-signal “dots” surrounded by areas of bright signal intensity, known as the “dot-in-circle” sign, which is highly specific for mycetoma. Surgical biopsy confirmed the diagnosis of bacterial mycetoma in this patient. Mycetoma can lead to progressive deformity and loss of function, as well as possible limb amputation in the case of delayed diagnosis or misdiagnosis. The “dot-in-circle” sign on magnetic resonance imaging can assist in rendering a final diagnosis and distinguish mycetoma from other etiologies of a soft tissue mass, such as a sarcoma or benign soft tissue lesions. Keywords: Infection, Mycetoma, Sarcoma, Dot-in-circle, Magnetic resonance imaging

Purpose The use of IMRT for the treatment of breast cancer has been growing considerably in our institution since 2009. Alternatively, helical tomotherapy (HT) using a field width of 2.5 and 5 cm (HT_FW_5), volumetric-modulated arc therapy (VMAT), or proton therapy with pencil-beam scanning (PT-PBS) have also been used to reduce treatment duration or optimize organ-at-risk (OAR) sparing. The purpose of this study was to compare the 4 treatment modalities available at our site. Patients and methods We studied 10 patients treated for breast cancer with lymph node involvement. The prescribed dose was 51.8 Gy to the breast with a simultaneous integrated boost up to 63 Gy, and 50.4 Gy to lymph nodes in 28 fractions. The CTV was delineated according to ESTRO Guidelines. Dosimetric planning in routine clinical practice was performed using HT_FW_2.5. The approved clinical plan was compared to the 3 other plans. Dosimetric goals for PTV coverage were D95% ≥ 95% and D2% ≤ 107% of the prescribed dose. Mean and maximum doses to OAR were recorded. Results HT_FW_5 and VMAT plans ensure equivalent or even better PTV coverage compared to the initial clinically approved plan but at the cost of poorer OAR sparing. PT_PBS plans showed that an excellent PTV coverage can be maintained with significantly lower doses to OAR. Conclusion HT_FW_5 and VMAT plans allow a significant reduction of treatment duration and can be a good alternative to HT_FW_2.5 for specific populations. HT_FW_2.5 could be chosen for patients at higher risk of side effects. In addition, PT_PBS should be considered in the near future as it has been shown to have a major potential benefit to lower the risk of side effects with the same level of PTV coverage.

Peripheral nerve sheath tumors (PNSTs) account for ~ 5% of soft tissue neoplasms and are responsible for a wide spectrum of morbidities ranging from localized neuropathy to fulminant metastatic spread and death. MR imaging represents the gold standard for identification of these neoplasms, however, current anatomic MR imaging markers do not reliably detect or differentiate benign and malignant lesions, and therefore, biopsy or excision is required for definitive diagnosis. Diffusion-weighted MR imaging (DWI) serves as a useful tool in the evaluation and management of PNSTs by providing functional information regarding the degree of diffusion, while diffusion tensor imaging (DTI) aids in determining the directional information of predominant diffusion and has been shown to be particularly useful for pre-operative planning of these tumors by delineating healthy and pathologic fascicles. The article focuses on these important neurogenic lesions, highlighting the current utility of diffusion MR imaging and future directions including computerized radiomic analysis. KEY POINTS: • Anatomic MRI is moderately accurate in differentiating benign from malignant PNST. • Diffusion tensor imaging facilitates pre-operative planning of PNSTs by depicting neuropathy and tractography. • Radiomics will likely augment current observer-based diagnostic criteria for PNSTs.

Purpose Medullary thyroid carcinoma (MTC) is characterized by a high rate of metastasis. In this study we evaluated the ability of [18F]DOPA PET/ceCT to stage MTC in patients with suspicious thyroid nodules and pathologically elevated serum calcitonin (Ctn) levels prior to total thyroidectomy and lymph node (LN) dissection. Methods A group of 32 patients with sonographically suspicious thyroid nodules and pathologically elevated basal Ctn (bCtn) and stimulated Ctn (sCtn) levels underwent DOPA PET/ceCT prior to surgery. Postoperative histology served as the standard of reference for ultrasonography and DOPA PET/ceCT region-based LN staging. Univariate and multivariate regression analyses as well as receiver operating characteristic analysis were used to evaluate the correlations between preoperative and histological parameters and postoperative tumour persistence or relapse. Results Primary MTC was histologically verified in all patients. Of the 32 patients, 28 showed increased DOPA decarboxylase activity in the primary tumour (sensitivity 88%, mean SUVmax 10.5). Undetected tumours were exclusively staged pT1a. The sensitivities of DOPA PET in the detection of central and lateral metastatic neck LN were 53% and 73%, in contrast to 20% and 39%, respectively, for neck ultrasonography. Preoperative bCtn and carcinoembryonic antigen levels as well as cN1b status and the number of involved neck regions on DOPA PET/ceCT were predictive of postoperative tumour persistence/relapse in the univariate regression analysis (P

Objective To evaluate the diagnostic performance of [68Ga]Ga-PSMAHBED-CC conjugate 11 positron emission tomography (PSMA-PET) in the early detection of metastases in patients with biochemical recurrence (BCR) after radical prostatectomy (RP) for clinically non-metastatic prostate cancer, to compare it to CT/MRI alone and to assess its impact on further therapeutic decisions. Material and methods We retrospectively assessed 117 consecutive hormone-naïve BCR patients who had 68Ga-PSMA 11 PET/CT (n = 46) or PET/MRI (n = 71) between May 2014 and January 2017. BCR was defined as two PSA rises above 0.2 ng/ml. Two dedicated uro-oncological imaging experts (radiology/nuclear medicine) reviewed separately all images. All results were presented in a blinded sequential fashion to a multidisciplinary tumorboard in order to assess the influence of PSMA-PET imaging on decision-making. Results The median time from RP to BCR was 36 months (IQR 16–72). Overall, 69 (59%) patients received postoperative radiotherapy. Median PSA level at the time of imaging was 1.04 ng/ml (IQR 0.58–1.87). PSMA-positive lesions were detected in 100 (85.5%) patients. Detection rates were 65% for a PSA value of 0.2 to

BackgroundQuantification of cardiac output and pulmonary vascular resistance (PVR) are critical components of invasive hemodynamic assessment, and can be measured concurrently with pressures using phase contrast CMR flow during real-time CMR guided cardiac catheterization.MethodsOne hundred two consecutive patients underwent CMR fluoroscopy guided right heart catheterization (RHC) with simultaneous measurement of pressure, cardiac output and pulmonary vascular resistance using CMR flow and the Fick principle for comparison. Procedural success, catheterization time and adverse events were prospectively collected.ResultsRHC was successfully completed in 97/102 (95.1%) patients without complication. Catheterization time was 20±11min. In patients with and without pulmonary hypertension, baseline mean pulmonary artery pressure was 39±12mmHg vs. 18±4mmHg (p&nbsp

The 2016 RAD-AID Conference analyzed the accelerated global activity in the radiology community that is transforming medical imaging into an effective spearhead of health care capacity building in low- and middle-income countries. Global health efforts historically emphasized disaster response, crisis zones, and infectious disease outbreaks. However, the projected doubling of cancer and cardiovascular deaths in developing countries in the next 15 years and the need for higher technology screening and diagnostic technologies in low-resource regions, as articulated by the United Nations' new Sustainable Development Goals of 2016, is heightening the role of radiology in global health. Academic US-based radiology programs with RAD-AID chapters achieved a threefold increase in global health project offerings for trainees in the past 5 years. RAD-AID's nonprofit radiology volunteer corps continue to grow by more than 40% yearly, with a volunteer base of 5,750 radiology professionals, serving in 23 countries, donating close to 20,000 pro bono hours globally in 2016. As a high-technology specialty interfacing with nearly all medical and surgical disciplines, radiology underpins vital health technology infrastructure, such as digital imaging archives, electronic medical records, and advanced diagnosis and treatment, essential for long-term future health care capacity in underserved areas of the world.

In this review, we present the synthesis of the newly acquired knowledge concerning high dose-rate irradiations and the hopes that these new radiotherapy modalities give rise to. The results were presented at a recent symposium on the subject.

The article deals with the prevention of cancers only directly related to therapeutic radiation which are distinguished from "secondary cancer". The consideration of the risk of radiation-induced cancers after radiation therapy, although it is fortunately rare events, has become indispensable today. With a review of the literature, are detailed the various involved parameters. The age of the irradiated patient is one of the main parameters. The impact of the dose is also discussed based on the model used, and based on clinical data. Other parameters defining a radiation treatment are discussed one after the other: field with the example of Hodgkin's disease, the type of radiation and the participation of secondary neutrons, spreading and splitting. All these parameters are discussed according to each organ whose sensitivity is different. The article concludes with a list of recommendations to reduce the risk of radio-induced cancers. Even with the advent of conformal radiotherapy, intensity modulation, the modulated volume arctherapy, and the development of specific machinery for the extra-cranial stereotactic, the radiation therapist must consider this risk and use of reasonable and justified control imaging. Although they constitute a small percentage of cancers that occur secondarily after a first malignant tumor, radiation-induced cancers, can not and must not be concealed or ignored and justify regular monitoring over the long term, precisely adapted on the described parameters.

Radiology in low- and middle-income (developing) countries continues to make progress. Research and international outreach projects presented at the 2015 annual RAD-AID conference emphasize important global themes, including (1) recent slowing of emerging market growth that threatens to constrain the advance of radiology, (2) increasing global noncommunicable diseases (such as cancer and cardiovascular disease) needing radiology for detection and management, (3) strategic prioritization for pediatric radiology in global public health initiatives, (4) continuous expansion of global health curricula at radiology residencies and the RAD-AID Chapter Network's participating institutions, and (5) technologic innovation for recently accelerated implementation of PACS in low-resource countries.

Purpose To assess the planning, treatment, and follow-up strategies worldwide in dedicated proton therapy ocular programs. Methods and Materials Ten centers from 7 countries completed a questionnaire survey with 109 queries on the eye treatment planning system (TPS), hardware/software equipment, image acquisition/registration, patient positioning, eye surveillance, beam delivery, quality assurance (QA), clinical management, and workflow. Results Worldwide, 28,891 eye patients were treated with protons at the 10 centers as of the end of 2014. Most centers treated a vast number of ocular patients (1729 to 6369). Three centers treated fewer than 200 ocular patients. Most commonly, the centers treated uveal melanoma (UM) and other primary ocular malignancies, benign ocular tumors, conjunctival lesions, choroidal metastases, and retinoblastomas. The UM dose fractionation was generally within a standard range, whereas dosing for other ocular conditions was not standardized. The majority (80%) of centers used in common a specific ocular TPS. Variability existed in imaging registration, with magnetic resonance imaging (MRI) rarely being used in routine planning (20%). Increased patient to full-time equivalent ratios were observed by higher accruing centers ( P =.0161). Generally, ophthalmologists followed up the post–radiation therapy patients, though in 40% of centers radiation oncologists also followed up the patients. Seven centers had a prospective outcomes database. All centers used a cyclotron to accelerate protons with dedicated horizontal beam lines only. QA checks (range, modulation) varied substantially across centers. Conclusions The first worldwide multi-institutional ophthalmic proton therapy survey of the clinical and technical approach shows areas of substantial overlap and areas of progress needed to achieve sustainable and systematic management. Future international efforts include research and development for imaging and planning software upgrades, increased use of MRI, development of clinical protocols, systematic patient-centered data acquisition, and publishing guidelines on QA, staffing, treatment, and follow-up parameters by dedicated ocular programs to ensure the highest level of care for ocular patients.

The aim of this work is to perform Monte Carlo simulations of a proton pencil beam scanning machine, characterise the low-dose envelope of scanned proton beams and assess the differences between various approximations for nozzle geometry. Measurements and Monte Carlo simulations were carried out in order to describe the dose distribution of a proton pencil beam in water for energies between 100 and 220 MeV. Dose distributions were simulated by using a Geant4 Monte Carlo platform (TOPAS), and were measured in water using a two-dimensional ion chamber array detector. The beam source in air was adjusted for each configuration. Double Gaussian parameterisation was proposed for definition of the beam source model in order to improve simulations starting at the nozzle exit. Absolute dose distributions and field size factors were measured and compared with simulations. The influence of the high-density components present in the treatment nozzle was also investigated by analysis of proton phase spaces at the nozzle exit. An excellent agreement was observed between experimental dose distributions and simulations for energies higher than 160 MeV. However, minor differences were observed between 100 and 160 MeV, suggesting poorer modelling of the beam when the full treatment head was not taken into account. We found that the first ionisation chamber was the main cause of the tail component observed for low proton beam energies. In this work, various parameterisations of proton sources were proposed, thereby allowing reproduction of the low-dose envelope of proton beams and excellent agreement with measured data.

Background Cardiovascular magnetic resonance (CMR) fluoroscopy allows for simultaneous measurement of cardiac function, flow and chamber pressure during diagnostic heart catheterization. To date, commercial metallic guidewires were considered contraindicated during CMR fluoroscopy due to concerns over radiofrequency (RF)-induced heating. The inability to use metallic guidewires hampers catheter navigation in patients with challenging anatomy. Here we use low specific absorption rate (SAR) imaging from gradient echo spiral acquisitions and a commercial nitinol guidewire for CMR fluoroscopy right heart catheterization in patients. Methods The low-SAR imaging protocol used a reduced flip angle gradient echo acquisition (10° vs 45°) and a longer repetition time (TR) spiral readout (10 ms vs 2.98 ms). Temperature was measured in vitro in the ASTM 2182 gel phantom and post-mortem animal experiments to ensure freedom from heating with the selected guidewire (150 cm × 0.035″ angled-tip nitinol Terumo Glidewire). Seven patients underwent CMR fluoroscopy catheterization. Time to enter each chamber (superior vena cava, main pulmonary artery, and each branch pulmonary artery) was recorded and device visibility and confidence in catheter and guidewire position were scored on a Likert-type scale. Results Negligible heating (

Global health is an area for study, research, and practice that places a priority on improving health and achieving equity in health for all people worldwide. Global health emphasizes transnational health issues, determinants, and solutions;involvesmanydisciplines within and beyond the health sciences and promotes interdisciplinary collaboration; and is a synthesis of population-based prevention with individual

Purpose Recent in vivo investigations have shown that short pulses of electrons at very high dose rates (FLASH) are less harmful to healthy tissues but just as efficient as conventional dose-rate radiation to inhibit tumor growth. In view of the potential clinical value of FLASH and the availability of modern proton therapy infrastructures to achieve this goal, we herein describe a series of technological developments required to investigate the biology of FLASH irradiation using a commercially available clinical proton therapy system. Methods and Materials Numerical simulations and experimental dosimetric characterization of a modified clinical proton beamline, upstream from the isocenter, were performed with a Monte Carlo toolkit and different detectors. A single scattering system was optimized with a ridge filter and a high current monitoring system. In addition, a submillimetric set-up protocol based on image guidance using a digital camera and an animal positioning system was also developed. Results The dosimetric properties of the resulting beam and monitoring system were characterized; linearity with dose rate and homogeneity for a 12 × 12 mm2 field size were assessed. Dose rates exceeding 40 Gy/s at energies between 138 and 198 MeV were obtained, enabling uniform irradiation for radiobiology investigations of small animals in a modified clinical proton beam line. Conclusions This approach will enable us to conduct FLASH proton therapy experiments on small animals, specifically for mouse lung irradiation. Dose rates exceeding 40 Gy/s were achieved, which was not possible with the conventional clinical mode of the existing beamline.

International audience; The scope of this work was to develop a synthetic single crystal diamond dosimeter (SCDD-Pro) for accurate relative dose measurements of clinical proton beams in water. Monte Carlo simulations were carried out based on the MCNPX code in order to investigate and reduce the dose curve perturbation caused by the SCDD-Pro. In particular, various diamond thicknesses were simulated to evaluate the influence of the active volume thickness (e(AV)) as well as the influence of the addition of a front silver resin (250 µm in thickness in front of the diamond crystal) on depth-dose curves. The simulations indicated that the diamond crystal alone, with a small eAV of just 5 µm, already affects the dose at Bragg peak position (Bragg peak dose) by more than 2% with respect to the Bragg peak dose deposited in water. The optimal design that resulted from the Monte Carlo simulations consists of a diamond crystal of 1 mm in width and 150 µm in thickness with the front silver resin, enclosed by a water-equivalent packaging. This design leads to a deviation between the Bragg peak dose from the full detector modeling and the Bragg peak dose deposited in water of less than 1.2%. Based on those optimizations, an SCDD-Pro prototype was built and evaluated in broad passive scattering proton beams. The experimental evaluation led to probed SCDD-Pro repeatability, dose rate dependence and linearity, that were better than 0.2%, 0.4% ( in the 1.0-5.5 Gy min(-1) range) and 0.4% ( for dose higher than 0.05 Gy), respectively. The depth-dose curves in the 90-160 MeV energy range, measured with the SCDD-Pro without applying any correction, were in good agreement with those measured using a commercial IBA PPC05 plane-parallel ionization chamber, differing by less than 1.6%. The experimental results confirmed that this SCDD-Pro is suitable for measurements with standard electrometers and that the depth-dose curve perturbation is negligible, with no energy dependence and no significant dose rate dependence.

Objectives: We test the safety of transatrial pericardial access using small catheters, infusion of carbon dioxide (CO2) or iodinated contrast to facilitate sub-xiphoid access, and catheter withdrawal under full anticoagulation. Background: Sub-xiphoid pericardial access is required for electrophysiological and structural heart interventions. If present, an effusion protects the heart from needle injury by separating the myocardium from the pericardium. However, if the pericardium is ‘dry' then there is a significant risk of right ventricle or coronary artery laceration caused by the heart beating against the needle tip. Intentional right atrial exit is an alternative pericardial access route, through which contrast media could be infused to separate pericardial layers. Methods: Transatrial pericardial access was obtained in a total of 30 Yorkshire swine using 4Fr or 2.8Fr catheters. In 16 animals, transatrial catheters were withdrawn under anticoagulation and MRI was performed to monitor for pericardial hemorrhage. In 14 animals, iodinated contrast or CO2 was infused before sub-xiphoid access was obtained. Results: Small effusions (mean 18.5 ml) were observed after 4Fr (1.3 mm outer-diameter) but not after 2.8Fr (0.9 mm outer-diameter) transatrial catheter withdrawal despite full anticoagulation (mean activated clotting time 383 sec), with no hemodynamic compromise. Pericardial CO2 resorbed spontaneously within 15 min. Conclusions: Intentional transatrial exit into the pericardium using small catheters is safe and permits infusion of CO2 or iodinated contrast to separate pericardial layers and facilitate sub-xiphoid access. This reduces the risk of right ventricular or coronary artery laceration. 2.8Fr transatrial catheter withdrawal does not cause any pericardial hemorrhage, even under full anticoagulation. © 2014 Wiley Periodicals, Inc.

Purpose To describe the transvenous application of intracardiac echocardiography (ICE) for guidance during endovascular aortic repair (EVAR). Materials and Methods Eight patients with an infrarenal abdominal aortic aneurysm (AAA) and chronic renal failure were determined suitable for EVAR. The procedure was performed by deploying the transcaval and transiliac vein guidance of an ICE catheter to reduce the dosage of iodinated contrast medium. Multiple guidance parameters were assessed. The present study describes the EVAR procedure and postprocedure transabdominal ultrasound (US) follow-up results at 3–4 months. Results The eight procedures were completed by using transvenous ICE guidance. No contrast medium was used in five patients, and 3–20 mL of isoosmolar contrast medium was administered in the other three. No endoleaks were detected by ICE immediately after stent deployment. One patient who had a single functioning kidney developed renal failure that was attributed to manipulation-related cholesterol embolization. That patient became dependent on dialysis and died 3.5 months after the procedure. No endoleaks were detected at 3–4-month US follow-up in the other seven patients. Conclusions Transvenous ICE guidance is a promising method to reduce the dosage of iodinated contrast medium in patients with renal dysfunction undergoing EVAR. A prospective trial comparing this modality versus digital subtraction angiography guidance with iodinated contrast medium in terms of safety, accuracy, and long-term efficacy is recommended.

Introduction Intensity modulated radiotherapy allows to significantly reduce the toxicity to organs at risk (OAR) in radiotherapy of breast cancer while allowing proper coverage of the planning target volumes (PTV). The purpose of this study is to perform a dosimetric comparison of 3 TPS used in our department for the planning of rotational intensity modulated treatment of breast and the following regional nodes: supra and infraclavicular (level IV,III and II nodes) and internal mammary nodes (IMNs). Methods 10 patients treated for breast cancer and regional nodes (IV, III, II and IMNs) were selected (5 left breasts and 5 right breasts). Prescription doses, delivered in 28 fractions, are 50.4 Gy in the whole breast and the regional nodes, and 63 Gy in the tumor bed (integrated boost). Treatment plans were designed using the 3 following treatment planning systems: Eclipse 13.6 with Photon Optimizer inverse planning algorithm (Varian Medical Systems), RayStation 6.1.1.2 (RaySearch Laboratories AB) and TomoTherapy Planning Station (PS) with VoLO and TomoEdge (Accuray Inc.). Eclipse and RayStation plans were designed using modulated volumetric arc-therapy (VMAT) with 4 partial arcs of 230° amplitude each, while TomoTherapy plans were designed with dynamic jaws, a 5 cm field width and a modulation factor of 3.5. All plans were exported to Artiview (Aquilab) to calculate for each PTV the homogeneity index (HI = D2-D98/ D50), the CN conformal index (Riet, 1997), the volume covered by isodose 95% of the prescribed dose and the near-maximum dose (D2%). For each plan, the low-dose volume (V5Gy,) the mean doses to the heart, ipsilateral lung, contralateral lung and breast were recorded. Results Preliminary results involve 5 patients (3 left breasts and 2 right breasts) and are summarized in Table 1. All treatment plans met acceptable PTV coverage (V95% > 95% for each PTV) as well as OAR medical constraints that are based on our clinical experience. However in the regional nodes and in the breast, even at a certain distance from the tumor bed, some plans for the 3 TPS have D2% greater than 107% of the prescribed dose. Download : Download high-res image (121KB) Download : Download full-size image Conclusion This preliminary study shows that the 3 TPS presented here are reliable for the planning of rotational intensity modulated treatment of breast and the regional nodes. Further work will involve the inclusion of a higher number of patients to undertake a more in-depth statistical analysis.

Objectif de l’etude Etudier les facteurs predictifs d’une pathologie cerebrovasculaire apres cancer de l’enfant. Materiel et methode Il s’agissait d’un etude de cohorte French Childhood Cancer Survivor Study (FCCSS) : 7018 survivants a 5 ans d’un cancer de l’enfant traite avant 2001, dont 1193 pour une tumeur cerebrale, et suivis 24 ans en moyenne, par l’acces aux dossiers medicaux et aux donnees du Systeme national d’information interregimes de l’assurance maladie (Sniiram), ainsi qu’au moyen de l’envoi d’autoquestionnaires. Les radiotherapies recues par 4176 sujets, dont 1016, pour une tumeur cerebrale, ont ete reconstituees a l’aide de fantomes anthropomorphiques, et les doses de radiation recues au niveau des arteres cerebrales et d’autres structures d’interet ont ete estimees. Resultats Un total de 145 sujets a ete atteint d’un accident vasculaire cerebral, dont 72 apres une tumeur cerebrale et 134 apres la radiotherapie. Le type d’accident vasculaire cerebral n’a pas pu etre defini pour 24 patients, il etait ischemique pour 77 et hemorragique pour 44. Il n’a pas ete possible d’identifier de drogue ou de categorie de drogue augmentant le risque d’accident vasculaire cerebral. Dans une analyse multifactorielle, celui-ci etait plus important chez les sujets atteints d’une neurofibromatose de type I (NF1), et augmentait avec la dose de radiation recue au niveau des arteres cerebrales, le coefficient de risque etant plus eleve pour les accidents vasculaires cerebraux ischemiques, ainsi qu’avec la radiotherapie thoracique ou abdominale. Il n’a pas ete possible de mettre en evidence de role de la chirurgie des tumeurs cerebrales, que ce soit propre ou par interaction avec la radiotherapie, mais seuls 206 sujets traites pour une tumeur cerebrale n’avaient pas eu de chirurgie. Les sujets qui avaient recu de la radiotherapie, mais 30 Gy ou plus sur seulement moins de 5 % de la longueur des arteres cerebrales principales avaient un risque d’accident vasculaire cerebral augmente d’un facteur 2,8 (1,3–5,5). En revanche, il n’y avait pas d’evidence claire pour un role des doses faibles de rayonnements ionisants de un ou quelques Gy. Conclusion Cette etude n’a pas permis de mettre en evidence de role de la chimiotherapie ou de la chirurgie dans le risque de tumeur cerebrale, mais a permis de preciser et de quantifier le role de la radiotherapie cerebrale.

Resume Objectifs de l’etude La dosimetrie in vivo a pour objectif de detecter et de corriger les ecarts de traitements significatifs en radiotherapie. L’utilisation des imageurs portals permet de rendre ces controles rapides et riches en informations. De nombreux travaux ont ete publies sur ce sujet, mais aucune recommandation n’a ete etablie pour definir les niveaux de tolerance pour ces controles. Nous proposons une methodologie simple pour evaluer le niveau de tolerance global des resultats in vivo obtenus avec ces detecteurs plans. Materiels et methodes Dans un premier temps, les incertitudes liees a la methode de reconstruction ont ete evaluees. Elles ont ete determinees sur un ensemble de geometries, representative des situations cliniques, pour lesquelles 45 points de mesure de dose ont ete definis. Dans un deuxieme temps, il a ete realise une etude des variations induites par le cadre de la mesure in vivo en presence du patient afin de definir des niveaux d’actions realistes et adaptes a la routine clinique. Pour finir, une methodologie est proposee pour determiner si la methode, associee a ces niveaux de tolerance, permet de detecter des ecarts significatifs de traitements, superieures a 5 % a la dose prescrite. Resultats – conclusion En appliquant cette methodologie, nous avons conclu qu’un niveau de tolerance de 6,5 % (k = 2) pouvait etre associe a notre methode de dosimetrie in vivo. Il a ete montre que cette valeur permettait dans de nombreux cas de detecter des differences de 5 % de la dose prescrite. La dosimetrie in vivo de transmission ne peut pas pretendre detecter tous les ecarts de traitements, mais elle permet d’augmenter la securite des patients.

The RAD-AID Conference on International Radiology for Developing Countries is a yearly forum addressing global shortages of radiology that contribute to health care disparity. In this paper, the authors present key issues and consensus positions related to the planning, analyzing, implementing, and monitoring of radiology in limited-resource areas on the basis of presentations at the 2012 RAD-AID conference, to advocate for (1) economic development to build health care capacity, (2) multidisciplinary educational strategies, (3) innovative epidemiologic and infrastructural solutions tailored to community needs, (4) advanced technical solutions leveraging the widespread use of wireless telecommunications and phone-based portable devices, and (5) improved dialog across radiology and public health institutions for coordinating global health strategies.

Proton beam range is of major concern, in particular, when images used for dose computations are artifacted (for example in patients with surgically treated bone tumors). We investigated several conditions and methods for determination of computed tomography Hounsfield unit (CT-HU) calibration curves, using two different conversion schemes. A stoichiometric methodology was used on either kilovoltage (kV) or megavoltage (MV) CT images and the accuracy of the calibration methods was evaluated. We then studied the effects of metal artifacts on proton dose distributions using metallic implants in rigid phantom mimicking clinical conditions. MV-CT images were used to evaluate relative proton stopping power in certain high density implants, and a methodology is proposed for accurate delineation and dose calculation, using a combined set of kV- and MV-CT images. Our results show good agreement between measurements and dose calculations or relative proton stopping power determination (

International audience; Small diamond detectors are useful for the dosimetry of high-energy proton beams. However, linear energy transfer (LET) dependence has been observed in the literature with such solid state detectors. A novel synthetic diamond detector has recently become commercially available from the manufacturer PTW-Freiburg (PTW microDiamond type 60019). This study was designed to thoroughly characterize four microDiamond detectors in clinical proton beams, in order to investigate their response and their reproducibility in high LET regions. Very good dosimetric characteristics were observed for two of them, with good stability of their response (deviation less than 0.4% after a pre-irradiation dose of approximately 12 Gy), good repeatability (coefficient of variation of 0.06%) and a sensitivity of approximately 0.85 nC Gy(-1). A negligible dose rate dependence was also observed for these two microDiamonds with a deviation of the sensitivity less than 0.7% with respect to the one measured at the reference dose rate of 2.17 Gy min(-1), in the investigated dose rate range from 1.01 Gy min(-1) to 5.52 Gy min(-1). Lateral dose profile measurements showed the high spatial resolution of the microDiamond oriented with its stem perpendicular to the beam axis and with its small sensitive thickness of about 1 mu m in the scanning profile direction. Finally, no significant LET dependence was found with these two diamond dosimeters in comparison to a reference ionization chamber (model IBA PPC05). These good results were in accordance to the literature. However, this study showed also a non reproducibility between the devices in terms of stability, sensitivity and LET dependence, since the two other microDiamonds characterized in this work showed different dosimetric characteristics making them not suitable for proton beam dosimetry with a maximum difference of the peak-to-plateau ratio of 6.7% relative to the reference ionization chamber in a clinical 138 MeV proton beam.

Purpose To assess the benefits of using cardiac gated images for treatment planning of breast and internal mammary nodes. Patients and methods Inspiration breath hold computed tomography (CT) series acquired at prospectively gated diastolic phase were used for planning. Three different techniques were compared. Technique A used tangents and an internal mammary nodes field covering the three first inter-rib spaces; technique B used an extended internal mammary nodes including part of the medial breast in junction with tangential fields; the 3 rd technique used helical tomotherapy. For each technique, two treatment plans were performed: one plan (plan-01) where mean dose and V 25 to the heart were considered for plan evaluation and a second plan (plan-02) where the irradiation of the left anterior descending artery was minimized. Results V 25 to the heart was found to be less than 5% for all six plans. Mean doses to the heart were within 4.8 to 7.2 Gy. By attempting to lower the dose to the left anterior descending artery, heart D mean was decreased by 20–30% for the two techniques A and B while being unchanged for tomotherapy. Regarding target coverage, there was no marked difference between plans where only heart dose was considered (plans-01) and plans where the left anterior descending artery dose was minimized (plans-02). When the left anterior descending artery dose was part of plan evaluation, D mean to the left anterior descending artery could be decreased by 24, 19 and 9% for techniques A, B and tomotherapy respectively. The three techniques exposed segments of the left coronary to different levels of dose. Conclusion This study showed that evaluation of the dose to the left anterior descending artery coronary may change the treatment strategy. Cardiac gated images without IV contrast permitted a good visualization of the coronaries in order to optimize the dose on these structures. In addition to heart V 25, the dose to the coronaries should be included in prospective studies on radiotherapy related heart toxicity in association with all additional risk factors.

Introduction Due to organ motion/deformation, dose distribution from fraction to fraction might be usually different from the intended dose distribution optimized at the planning stage. To evaluate the actual delivered dose in the “patient of the day”, we developed a technique of dose computation in the deformed planning CT (pCTD) using an elastic registration from the kilovoltage-CBCT, with an optimized electron density assignment based on a mapping of CBCT information (pCTD,C). Methods Dose calculation was performed on successive kilovoltage CBCT (kV-CBCT) for patients treated with conformational or IMRT technique. The linac was a Varian Truebeam (Varian Medical System) equipped with a kV-CBCT system. Patient underwent to the planning CT (pCT) on a Toshiba Aquilon/LB model (Toshiba Medical System) and using Eclipse (Varian MS) for planning the treatment. The geometry of the “patient of the day” was acquired once a week with the same kV-CBCT protocol (half fan, 80 kV, 1049mAs). Rigid and elastic registrations of the CBCT to the pCT was made using ISOgray TPS (DOSIsoft S.A., France). The method was first validated using an anthropomorphic thorax phantom (CIRS, Inc., Norfolk, Virginia, USA) with or without added bolus to simulate morphological deformation. A routine was developed using MATLAB2017b to map CBCT information to the pCTD. Dose calculation was performed on the CBCT and pCTD using their respective calibration curve from HUCBCT and HUpCT to electron density. Results Dose calculation using an elastic registration method on an anthropomorphic phantom was quantified with a comparison of typical dose calculation computed with the pCTD,C and the CBCT. Dose distributions were in good agreement. Results on patients are pending and would be evaluated in term of dose prescription, PTV coverage and OARs sparing. Conclusions We evaluated a dose calculation method based on mapping of CBCT information. The method enables us to efficiently calculate dose distribution with a good accuracy to evaluate the true delivered dose fraction to fraction and to bring out differences from the planning treatment.

Resume Objectif de l’etude L’indication d’une radiotherapie externe est parfois posee chez des patients porteurs d’un stimulateur cardiaque. Ce traitement peut occasionner des dysfonctionnements lies soit a l’effet ionisant des rayons, soit a des interferences electromagnetiques. Nous avons repris le cas de patientes atteintes d’un cancer du sein traitees par une irradiation mammaire ou parietale, parfois aussi des aires ganglionnaires de drainage, pour evaluer la tolerance et les repercussions de la radiotherapie par rapport au stimulateur cardiaque. Patientes et methodes Plus de 900 patientes ont ete traitees par irradiation externe pour un cancer du sein de novembre 2008 a decembre 2009 dans notre departement par un accelerateur lineaire de haute energie (par photons X de 4 a 6 MV et electrons). Parmi ces dernieres, sept etaient porteuses d’un stimulateur cardiaque. Toutes les patientes ont ete irradiees dans le sein, la paroi thoracique ou les aires ganglionnaires. La dose totale prescrite etait de 50 Gy en 25 fractions dans le sein ou la paroi thoracique et de 46 Gy en 23 fractions dans les aires ganglionnaires. Un boost de 16 Gy en huit fractions etait indique chez certaines patientes traitees par chirurgie conservatrice. Le rythme cardiaque de toutes les patientes etait monitore pendant les seances et surveille par un medecin oncologue radiotherapeute. Tous les stimulateurs cardiaques ont ete controles par le cardiologue des patientes avant et apres l’irradiation. Resultats Sept patientes ont ete adressees dans notre departement pour radiotherapie postoperatoire dans le cadre d’un cancer du sein. Parmi ces sept patientes, seule une finalement s’est vue recuser la radiotherapie et a beneficie d’une mastectomie. Dans quatre cas, le stimulateur cardiaque a ete repositionne avant le debut de la radiotherapie. Six patientes âgees de 48 a 84 ans ont ete traitees par irradiation pour leur cancer du sein. Quatre patientes ont ete traitees par chirurgie conservatrice suivie d’une irradiation mammaire et deux par mastectomie suivie d’une irradiation de la paroi thoracique et des aires ganglionnaires sus- et sous-claviculaire et mammaire interne. La dose au stimulateur cardiaque a ete calculee et etait toujours inferieure a 2 Gy. Il n’a ete observe aucun dysfonctionnement des stimulateurs cardiaques pendant la radiotherapie. Conclusion La prise en charge multidisciplinaire incluant un eventuel changement de positionnement du stimulateur cardiaque avant radiotherapie et le monitoring quotidien ont permis le deroulement sans incident de la radiotherapie pour nos patientes. Il est neanmoins necessaire de mettre a jour des recommandations precisant la dose maximale tolerable aux differents constituants du stimulateur cardiaque.

Purpose In vivo dose verification is used to prevent major deviations between the prescribed dose and the dose really delivered to the patient. This work presents a quick and simple alternative method for verification of dose delivered to the patient using photon beams. During the treatment session, a transit dose is measured with the EPID and the dose in the patient is estimated from back projection of the portal dose. Methods and Materials The formalism for dose calculation is described. It is independent of the detector and has been validated for different beam energies using an ionization chamber (IC). Central axis doses estimated by this formalism were compared with measured dose. Subsequently, the IC was replaced by the EPID appropriately calibrated. The feasibility of the method and its applicability in clinical use has been evaluated on 3 8 patients treated with conformal therapy for various localizations. Results Ratios between stated and measured doses are reported. They are within the accepted tolerance of classical in vivo dosimetry (SD of 3.5%). Conclusions The proposed method for in vivo dose verification is very simple to implement and to use in clinics. Measurements can be repeated during several sessions giving the opportunity to built new strategies for the validation by statistical evaluation of the data. The trending of in vivo dose along the treatment becomes also possible. The number of checkable beams is also increased by this method.

With over 70,000 patients treated worldwide, protontherapy has an evolution on their clinical applications and technological developments. The ballistic advantage of the Bragg peak gives the possibility of getting a high conformation of the dose distribution to the target volume. Protontherapy has accumulated a considerable experience in the management of selected rare malignancies such as uveal melanomas and base of the skull chordomas and chondrosarcomas. The growing interest for exploring new and more common conditions, such as prostate, lung, liver, ENT, breast carcinomas, as well as the implementation of large pediatric programs advocated by many experts has been challenged up to now by the limited access to operational proton facilities, and by the relatively slow pace of technical developments in terms of ion production, beam shaping and modelling, on-line verification etc. One challenge today is to deliver dynamic techniques with intensity modulation in clinical facilities as a standard treatment. We concentrate in this paper on the evolution of clinical indications as well as the potentialities of new technological concepts on ion production, such as dielectric walls and laser-plasma interactions. While these concepts could sooner or later translate into prototypes of highly compact equipments that would make easier the implantation of cost-effective hospital-based facilities, the feasibility of their clinical use must still be proved.

In proton therapy, the relative biological effectiveness (RBE) depends on various types of parameters such as linear energy transfer (LET). An analytical model for LET calculation exists (Wilkens' model), but secondary particles are not included in this model. In the present study, we propose a correction factor, L sec, for Wilkens' model in order to take into account the LET contributions of certain secondary particles. This study includes secondary protons and deuterons, since the effects of these two types of particles can be described by the same RBE-LET relationship. L sec was evaluated by Monte Carlo (MC) simulations using the GATE/GEANT4 platform and was defined by the ratio of the LET d distributions of all protons and deuterons and only primary protons. This method was applied to the innovative Pencil Beam Scanning (PBS) delivery systems and L sec was evaluated along the beam axis. This correction factor indicates the high contribution of secondary particles in the entrance region, with L sec values higher than 1.6 for a 220 MeV clinical pencil beam. MC simulations showed the impact of pencil beam parameters, such as mean initial energy, spot size, and depth in water, on L sec. The variation of L sec with these different parameters was integrated in a polynomial function of the L sec factor in order to obtain a model universally applicable to all PBS delivery systems. The validity of this correction factor applied to Wilkens' model was verified along the beam axis of various pencil beams in comparison with MC simulations. A good agreement was obtained between the corrected analytical model and the MC calculations, with mean-LET deviations along the beam axis less than 0.05 keV μm(-1). These results demonstrate the efficacy of our new correction of the existing LET model in order to take into account secondary protons and deuterons along the pencil beam axis.

Background In current practice, the diagnostic yield of endomyocardial biopsy is low because the procedure is performed ‘blind’ using X-ray fluoroscopy guidance and because many pathologies affect the myocardium in a patchy distribution. We hypothesized that biopsy performed under direct realtime MRI guidance would have superior diagnostic yield, in an animal model of focal myocardium pathology.

After a request for proposal initiated by National Institute against cancer (INCa) in 2005, three French centers in France started tomotherapy in the first semester of 2007. A national policy of evaluation was performed to study the feasibility of this innovative technique and to compare the interest of helicoidal tomotherapy with other modalities of conformal therapy. Common protocols have been designed to facilitate this evaluation. Description of dose, IMRT levels and constraints are achieved according to each selected indication as: sarcoma, head and neck tumors, lung cancer, mesothelioma, bone metastases, anal carcinoma and craniospinal irradiation.

Background Conventional guidewires are not suitable for use during cardiovascular magnetic resonance (CMR) catheterization. They employ metallic shafts for mechanical performance, but which are conductors subject to radiofrequency (RF) induced heating. To date, non-metallic CMR guidewire designs have provided inadequate mechanical support, trackability, and torquability. We propose a metallic guidewire for CMR that is by design intrinsically safe and that retains mechanical performance of commercial guidewires. Methods The NHLBI passive guidewire is a 0.035” CMR-safe, segmented-core nitinol device constructed using short nitinol rod segments. The electrical length of each segment is less than one-quarter wavelength at 1.5 Tesla, which eliminates standing wave formation, and which therefore eliminates RF heating along the shaft. Each of the electrically insulated segments is connected with nitinol tubes for stiffness matching to assure uniform flexion. Iron oxide markers on the distal shaft impart conspicuity. Mechanical integrity was tested according to International Organization for Standardization (ISO) standards. CMR RF heating safety was tested in vitro in a phantom according to American Society for Testing and Materials (ASTM) F-2182 standard, and in vivo in seven swine. Results were compared with a high-performance commercial nitinol guidewire. Results The NHLBI passive guidewire exhibited similar mechanical behavior to the commercial comparator. RF heating was reduced from 13 °C in the commercial guidewire to 1.2 °C in the NHLBI passive guidewire in vitro, using a flip angle of 75°. The maximum temperature increase was 1.1 ± 0.3 °C in vivo, using a flip angle of 45°. The guidewire was conspicuous during left heart catheterization in swine. Conclusions We describe a simple and intrinsically safe design of a metallic guidewire for CMR cardiovascular catheterization. The guidewire exhibits negligible heating at high flip angles in conformance with regulatory guidelines, yet mechanically resembles a high-performance commercial guidewire. Iron oxide markers along the length of the guidewire impart passive visibility during real-time CMR. Clinical translation is imminent.

Mandatory in several countries, in vivo dosimetry has been recognized as one of the next milestones in radiation oncology. Our department has implemented clinically an EPID based in vivo dosimetry system, EPIgray, by DOSISOFT S.A., since 2006. An analysis of the measurements per linac and energy over a two‐year period was performed, which included a more detailed examination per technique and treatment site over a six‐month period. A comparison of the treatment planning system doses and the doses estimated by EPIgray shows a mean of the differences of 1.9% (±5.2%) for the two‐year period. The 3D conformal treatment plans had a mean dose difference of 2.0% (±4.9%), while for intensity‐modulated radiotherapy and volumetric‐modulated arc therapy treatments the mean dose difference was −3.0 (±5.3%) and −2.5 (±5.2%), respectively. In addition, root cause analyses were conducted on the in vivo dosimetry measurements of two breast cancer treatment techniques, as well as prostate treatments with intensity‐modulated radiotherapy and volumetric‐modulated arc therapy. During the breast study, the dose differences of breast treatments in supine position were correlated to patient setup and EPID positioning errors. Based on these observations, an automatic image shift correction algorithm is developed by DOSIsoft S.A. The prostate study revealed that beams and arcs with out‐of‐tolerance in vivo dosimetry results tend to have more complex modulation and a lower exposure of the points of interest. The statistical studies indicate that in vivo dosimetry with EPIgray has been successfully implemented for classical and complex techniques in clinical routine at our institution. The additional breast and prostate studies exhibit the prospects of EPIgray as an easy supplementary quality assurance tool. The validation, the automatization, and the reduction of false‐positive results represent an important step toward adaptive radiotherapy with EPIgray. PACS number(s): 87.53.Bn, 87.55.Qr, 87.56.Fc, 87.57.uq

To determine the relationship between the dose to the inner ear or pituitary gland and radiation-induced late effects of skull base radiation therapy.140 patients treated between 2000 and 2008 were considered for this study. Hearing loss and endocrine dysfunction were retrospectively reviewed on pre- and post-radiation therapy audiometry or endocrine assessments. Two normal tissue complication probability (NTCP) models were considered (Lyman-Kutcher-Burman and log-logistic) whose parameters were fitted to patient data using receiver operating characteristics and maximum likelihood analysis. The method provided an estimation of the parameters of a generalized equivalent uniform dose (gEUD)-based NTCP after conversion of dose-volume histograms to equivalent doses.All 140 patients had a minimum follow up of 26 months. 26% and 44% of patients experienced mild hearing loss and endocrine dysfunction, respectively. The fitted values for TD50 and γ50 ranged from 53.6 to 60.7 Gy and from 1.9 to 2.9 for the inner ear and were equal to 60.6 Gy and 4.9 for the pituitary gland, respectively. All models were ranked equal according to Akaike's information criterion.Mean dose and gEUD may be used as predictive factors for late ear and pituitary gland late complications after skull base proton and photon radiation therapy.In this study, we have reported mean dose effects and dose-response relationship of small organs at risk (partial volumes of the inner ear and pituitary gland), which could be useful to define optimal dose constraints resulting in an improved therapeutic ratio.

Background Realtime MR enables radiation free guidance for right heart catheterization (RHC). In addition to catheter navigation for sampling of invasive pressures and blood oxygen saturations, MR permits concomitant assessment of cardiac chamber volumes and cardiac output with phase contrast flow measurements. By performing repeat measurements under different physiological provocations (e.g. saline volume challenge, inhaled nitric oxide, or exercise), diagnostic yield increases by revealing symptoms and pathologic findings not apparent at rest. Herein we present the NIH experience of MR RHC to date.