Optical coherence tomography provides images similar to histology and allows the performance of extensive measurements of drug-eluting metal stents in animal ureters.

Optical coherence tomography (OCT) images and histology images of metal stents (MSs) inserted in animal ureters were compared, and the reliability of an OCT-based automated method for the performance of quantitative evaluation of ureteral MSs was evaluated. A zotarolimus-eluting metal stent (ZES) and a bare metal stent (BMS) were inserted in each ureter of ten pigs and six rabbits. OCT was performed in unobstructed stented ureters. Histopathologic examination of the stented ureters embedded in glycol-methacrylate took place. Quadrants of OCT images were compared to their respective histologic images by employing two independent observers who delineated different layers in the quadrants of OCT images and correlated them to the respective histologic quadrants. Manual (integrated OCT device software) and automated measurements of the OCT images using an automated strut detection method were compared. The observers highly agreed on the delineation of urothelium from the lamina propria and the lamina propria from the muscle layer of the ureteral wall. The algorithm measurements were similar to the manual measurements, and the algorithm proved to be reliable in the evaluation of ureteral MSs. Significantly higher endothelial hyperplasia of the BMSs in comparison to the ZESs was also quantitatively demonstrated by the strut detection method. OCT proved to be a reliable method for the evaluation of ureteral MSs. OCT provided images of the stented ureteral lumen similar to light microscopy quality. Measurements of the stented ureter are reliably performed by the automated strut detection method.

Expanding the medical physicist curricular and professional programme to include Artificial Intelligence.

PURPOSE: To provide a guideline curriculum related to Artificial Intelligence (AI), for the education and training of European Medical Physicists (MPs). MATERIALS AND METHODS: The proposed curriculum consists of two levels: Basic (introducing MPs to the pillars of knowledge, development and applications of AI, in the context of medical imaging and radiation therapy) and Advanced. Both are common to the subspecialties (diagnostic and interventional radiology, nuclear medicine, and radiation oncology). The learning outcomes of the training are presented as knowledge, skills and competences (KSC approach). RESULTS: For the Basic section, KSCs were stratified in four subsections: (1) Medical imaging analysis and AI Basics; (2) Implementation of AI applications in clinical practice; (3) Big data and enterprise imaging, and (4) Quality, Regulatory and Ethical Issues of AI processes. For the Advanced section instead, a common block was proposed to be further elaborated by each subspecialty core curriculum. The learning outcomes were also translated into a syllabus of a more traditional format, including practical applications. CONCLUSIONS: This AI curriculum is the first attempt to create a guideline expanding the current educational framework for Medical Physicists in Europe. It should be considered as a document to top the sub-specialties' curriculums and adapted by national training and regulatory bodies. The proposed educational program can be implemented via the European School of Medical Physics Expert (ESMPE) course modules and - to some extent - also by the national competent EFOMP organizations, to reach widely the medical physicist community in Europe.

Deep brain stimulation for secondary dystonia: results in 8 patients.

BACKGROUND: Dystonia is a medically intractable condition characterized by involuntary twisting movements and/or abnormal postures. Deep Brain Stimulation (DBS) has been used successfully in various forms of dystonia. In the present study, we report on eight patients with secondary dystonia, treated with DBS in our clinic. METHOD: Eight patients (five males, three females) underwent DBS for secondary dystonia. The etiology of dystonia was cerebral palsy (n = 2), drug-induced (n = 1), post encephalitis (n = 2) and postanoxic dystonia (n = 3). The functional capacity was evaluated before and after surgery with the use of Burke-Fahn-Mardsen Dystonia Rating Scale (BFM scale), both movement and disability scale (MS and DS, respectively). The target for DBS was the globus pallidus internus (GPi) in 7 patients and in one patient, with postanoxic damaged pallidum, the ventralis oralis anterior (Voa) nucleus. Brain perfusion scintigraphy using Single Photon Emission Computed Tomography (SPECT) was performed in two separate studies for each patient, one in the "off-DBS" and the other in the "on-DBS" state. FINDINGS: Postoperative both MS and DS scores were found to be significantly lower compared to preoperative scores (p = 0.018 and p = 0.039, respectively). Mean improvement rate after DBS was 41.4% (0-94.3) and 29.5% (0-84.2) in MS and DS scores, respectively. The SPECT Scan, during the "on-DBS" state, showed a decrease in regional cerebral blood flow (rCBF), compared to the "off-DBS" state. CONCLUSIONS: Our results seem promising in the field of secondary dystonia treatment. More studies with greater number of patients and longer follow-up periods are necessary in order to establish the role of DBS in the management of secondary dystonia. Finally, the significance of brain SPECT imaging in the investigation of dystonia and functional effects of DBS should be further evaluated.

Ureteral injuries during gynecologic surgery: treatment with a minimally invasive approach.

PURPOSE: To report the safety and efficacy of percutaneous nephrostomy and primary antegrade recanalization for treatment of iatrogenic ureteral strictures after gynecologic surgery. PATIENTS AND METHODS: Ten women had symptoms suggestive of ureteral obstruction during the immediate postoperative period (5 days-1 week after surgery). Under analgesia and conscious sedation, standard percutaneous nephrostomy was performed, and a long 7F sheath was placed in the upper ureter. The obstructions were traversed with the aid of a 0.0035-inch Glidewire and a 5F angled Glide catheter (Terumo, Japan). Subsequently, the areas were dilated with angioplasty balloons to a maximum diameter of 7 mm. Finally, an 8F percutaneous internal/external nephroureteral drainage stent was inserted to secure ureteral patency. Follow-up was carried out by serial nephrostomography until removal of the stent and by renal ultrasonography thereafter. RESULTS: Twelve obstructions with a mean length of 1.4 cm (range 0.4-1.9 cm) were managed. The technical success rate was 100%. No major complications occurred, and normal renal function was restored. The mean follow-up was 12 months. In 60% of the patients, a patent ureter was depicted at 1 week, whereas in four patients, repeat dilation of the obstructed segment was required. The stents were removed after a mean period of 4.8 weeks. CONCLUSION: Percutaneous nephrostomy and primary antegrade ureteral balloon dilation is safe and efficacious for treating ureteral injury after pelvic surgery and obviates open surgical manipulations.

A theoretical model evaluating the angular distribution of luminescence emission in X-ray scintillating screens.

The aim of this study was to examine the angular distribution of the light emitted from radiation-excited scintillators in medical imaging detectors. This distribution diverges from Lambert's cosine law and affects the light emission efficiency of scintillators, hence it also affects the dose burden to the patient. In the present study, the angular distribution was theoretically modeled and was used to fit experimental data on various scintillator materials. Results of calculations revealed that the angular distribution is more directional than that predicted by Lambert's law. Divergence from this law is more pronounced for high values of light attenuation coefficient and thick scintillator layers (screens). This type of divergence reduces light emission efficiency and hence it increases the incident X-ray flux required for a given level of image brightness.

Virtual endoscopy in the diagnosis of an adult double tracheal bronchi case.

We report a case of ipsilateral double tracheal bronchi supplying a tracheal lobe in a 42-year-old man, who presented with a 10-year history of recurrent respiratory infections. Diagnosis was established by chest computed tomography (CCT), virtual endoscopy and bronchoscopy. Both bronchi were surgically resected along with the right upper lobe of the lung and the associated tracheal lobe. To our knowledge, this is the first report of ipsilateral double tracheal bronchi in the adult life to be diagnosed and treated on the basis of modern radiological techniques and especially virtual endoscopy findings.

SU-E-T-463: Biological-Based Optimization and VMAT is Unnecessary for Stereotactic Body Radiation Therapy.

PURPOSE: This study shows that there is no clear dosimetric benefit of biological-based optimization for either fixed-beam IMRT or VMAT. Other than shorter delivery times, even VMAT does not offer additional advantage to fixed-beam IMRT. METHODS: A small number of patients for lung, pancreas, spine and brain CA were planned with fixed-beam IMRT, optimized with (gEUD) and without (DV) biological objectives and, also planned for VMAT with and without gEUD, for comparison. For the lung and brain cases, a non-coplanar 7-11 beam arrangement was used for fixed- beam IMRT and a coplanar 'hybrid' arc simulated VMAT with beams set every 5° spacing. For the other treatment sites, all beams were coplanar. For each case, the fixed-beam IMRT and VMAT plans were optimized with the same objectives. It is important to note that, only 2 segments/beam were allowed for each plan, in order to create small fluence modulation, appropriate for small target volumes during SBRT. RESULTS: For all plans we noticed that there were minor or no dosimetric differences between fixed- beam IMRT and VMAT, whether DV or gEUD objectives were used or whether fixed-beam IMRT or VMAT is used. Keeping the level of beam modulation as-low-as possible, for small SBRT targets, one can show that VMAT with or without gEUD optimization does not offer any dosimetric advantage against fixed-beam IMRT with multiple non-coplanar beams. This is against the expectation that gEUD-optimization can Result superior plans than DV-optimization. The difference is that, for small target volumes like those encountered in SBRT, the complexity of the fluence is not as high as in large field intensity modulated cases. CONCLUSIONS: The fact that VMAT with or without gEUD can produce as good plans as fixed-IMRT does not make VMAT a preferred treatment modality, other than the fact that requires reduced treatment time.

SU-E-I-88: Realistic Pathological Simulations of the NCAT and Zubal Anthropomorphic Models, Based on Clinical PET/CT Data.

PURPOSE: In the present study a patient-specific dataset of realistic PET simulations was created, taking into account the variability of clinical oncology data. Tumor variability was tested in the simulated results. A comparison of the produced simulated data was performed to clinical PET/CT data, for the validation and the evaluation of the procedure. METHODS: Clinical PET/CT data of oncology patients were used as the basis of the simulated variability inserting patient-specific characteristics in the NCAT and the Zubal anthropomorphic phantoms. GATE Monte Carlo toolkit was used for simulating a commercial PET scanner. The standard computational anthropomorphic phantoms were adapted to the CT data (organ shapes), using a fitting algorithm. The activity map was derived from PET images. Patient tumors were segmented and inserted in the phantom, using different activity distributions. RESULTS: The produced simulated data were reconstructed using the STIR opensource software and compared to the original clinical ones. The accuracy of the procedure was tested in four different oncology cases. Each pathological situation was illustrated simulating a) a healthy body, b) insertion of the clinical tumor with homogenous activity, and c) insertion of the clinical tumor with variable activity (voxel-by-voxel) based on the clinical PET data. The accuracy of the presented dataset was compared to the original PET/CT data. Partial Volume Correction (PVC) was also applied in the simulated data. CONCLUSIONS: In this study patient-specific characteristics were used in computational anthropomorphic models for simulating realistic pathological patients. Voxel-by-voxel activity distribution with PVC within the tumor gives the most accurate results. Radiotherapy applications can utilize the benefits of the accurate realistic imaging simulations, using the anatomicaland biological information of each patient. Further work will incorporate the development of analytical anthropomorphic models with motion and cardiac correction, combined with pathological patients to achieve high accuracy in tumor imaging. This research was supported by the Joint Research and Technology Program between Greece and France; 2009-2011 (protocol ID: 09FR103).

SU-E-I-90: Fast and Robust Algorithm Towards Vessel Lumen and Stent Strut Detection in Optical Coherence Tomography.

PURPOSE: Optical Coherence Tomography (OCT) is a catheter-based imaging method that employs near-infrared light to produce high-resolution cross-sectional intravascular images. We propose a new segmentation technique for automatic lumen area extraction and stent strut detection in intravascular OCT images for the purpose of quantitative analysis of neointimal hyperplasia (NIH). METHODS: Two clinical dataset of frequency-domainOCT scans of the human femoral artery were analyzed. First, a segmentation method based on Fuzzy C-Means (FCM) clustering and Wavelet Transform (WT) was applied towards inner luminal contour extraction. Subsequently, stent strut positions were detected by utilizing metrics derived from the local maxima of the wavelet transform into the FCM membership function. RESULTS: The inner lumen contour and the position of stent strut were extracted with very high accuracy. Compared with manual segmentation by an expert physician, the automatic segmentation had an average overlap value of 0.917 ± 0.065 for all OCT images included in the study. The strut detection procedure successfully identified 6.7 ± 0.5 struts for each OCT image. CONCLUSIONS: A new fast and robust automatic segmentation technique combining FCM and WT for lumen border extraction and strut detection in intravascular OCT images was designed and implemented. The proposed algorithm may be employed for automated quantitative morphological analysis of in-stent neointimal hyperplasia.

An experimental environment for the production, exchange and discussion of fused radiology images, for the management of patients with residual brain tumour disease.

The present work aims to display the use of groupware as a tool for better management of the available resources (human, computing and imaging) within the University Hospital of Patras, Greece for the task of managing patients with postoperative residual brain tumour. Emphasis is given to the additional information that can be revealed and taken into account from novel image processing techniques, developed by our group, and the central role of the Medical Physicist in the groupware. Fused images, produced by the combination of CT, MR and SPECT representations of the brain, contain both anatomical and functional information and comprise a new representation of reality. Medical experts, unfamiliar with this new representation, form a groupware for the task of interpreting them and providing better services to the patient. Groupware procedures, facilitated by modern network technology, bring experts' tacit knowledge to the surface and facilitate its exchange.