A highly-compact and ultra-fast homogeneous electromagnetic calorimeter based on oriented lead tungstate crystals

Progress in high-energy physics has been closely tied to the development of high-performance electromagnetic calorimeters. Recent experiments have demonstrated the possibility to significantly accelerate the development of electromagnetic showers inside scintillating crystals typically used in homogeneous calorimeters based on scintillating crystals when the incident beam is aligned with a crystallographic axis to within a few mrad. In particular, a reduction of the radiation length has been measured when ultrarelativistic electron and photon beams were incident on a high-Z scintillator crystal along one of its main axes. Here, we propose the possibility to exploit this physical effect for the design of a new type of compact e.m. calorimeter, based on oriented ultra-fast lead tungstate (PWO-UF) crystals, with a significant reduction in the depth needed to contain electromagnetic showers produced by high-energy particles with respect to the state-of-the-art. We report results from tests of the crystallographic quality of PWO-UF samples via high-resolution X-ray diffraction and photoelastic analysis. We then describe a proof-of-concept calorimeter geometry defined with a Geant4 model including the shower development in oriented crystals. Finally, we discuss the experimental techniques needed for the realization of a matrix of scintillator crystals oriented along a specific crystallographic direction. Since the angular acceptance for e.m. shower acceleration depends little on the particle energy, while the decrease of the shower length remains pronounced at very high energy, an oriented crystal calorimeter will open the way for applications at the maximum energies achievable in current and future experiments. Such applications span from forward calorimeters, to compact beam dumps for the search for light dark matter, to source-pointing space-borne γ-ray telescopes, to decrease the size and the cost of the calorimeter needed to fully contain e.m. showers initiated by GeV to TeV particles

Isolated abducens nerve palsy due to acute sphenoiditis

The aim of this paper was to describe a patient affected by isolated abducens nerve palsy and visual disturbances due to a bilateral acute paranasal sinus infection. Patient medical records and imaging studies were reviewed, as well as the literature on the topic. Our patient presented an upper respiratory tract infection, associated with fever, severe progressively worsening headache and diplopia. Physical examination demonstrated right-sided sixth cranial nerve palsy. Imaging studies were consistent with bilateral pan-sinusal inflammatory disease. The patient was initially treated with antibiotics and betamethasone; upon 48 hours, due to the persistence of symptoms, she underwent sinuses drainage by functional endoscopic sinus surgery. After the complete resolution of the infection, at the control MRI study a Dorello's canal was demonstrated on the right side. Cranial nerve palsies associated to paranasal sinus infection have already been reported; however in this case we evidenced a direct correlation between the sinusal (sphenoidal) involvement and the abducens nerve

Lymphoscintigraphy (LS) in Oral Cavity Cancer (OCC) as a tool for a tailored surgical approach through selective and modified lymph-adenectomy: preliminary report

Aim: The purpose of the study was to assess the role of LS as a simple and widely accessible method with a favorable cost/benefit ratio in improving OCC staging and surgical appropriateness and implementing a tailored surgical approach to cervical lymph node dissection. The aim was to assess the lymphatic drainage in OCC through LS, in order to identify the percentage of patients with a lymphatic drainage beyond the compart- ments classically included in tumor surgery, and extend lymphadenecto- my to the side of abnormal lymphatic drainage evaluating the metastatic status of excised lymph nodes. Method: we enrolled 7 consecutive pa- tients (4 female, 3 male, median age 74±4.2 yo) affected by OCC sched- uled for surgery. The day before surgery all patients underwent LS with planar and SPECT/CT images acquisition comprising head and neck regions, after the administration of 99mTc-nanocoll (median 74±2.1 MBq) divided into injections (median 3±1) performed around the OCC, with lymph nodal drainage identification. Patients underwent tumor ecxision and lymphadenectomy of usual laterocervical compartment (de- pending on tumor localization) and radioguided surgery of additional sites of lymphatic drainage as shown by LS. Anatomo-pathological anal- ysis of tumor and lymph nodes was performed. Results: in 4 cases the tumor was in the tongue; in 1 case in the upper right dental arch and in 2 cases in the palate. Out of 7 patients, 3 (42%) showed laterocervical lymphatic drainage both ipsilateral and contralateral (LII, LIV and LIII respectively) to tumor. In 1 of these 3 cases (33%), metastasis was iden- tified in the contralateral cervical lymph nodes (LIII). In the remaining 4 cases the lymphatic drainage was only ipsilateral to tumor and lymph nodes metastases were observed in 2 cases (50%). Conclusions: Although the results of this study are limited and preliminary, it has been possible to observe that the lymphatic drainage from OCC can be abnor- mal, namely contralateral to tumor site in cervical region, in a non- negligible percentage of cases (42% overall), with possible cervical lymph nodes metastatic involvement (33% of cases and 14% overall). Therefore LS could be a useful tool to properly map the lymphatic drain- age from OCC, in order to perform a selective and modified lymphadenectomy (different from classical one) with potential benefits for patients in terms of more accurate cancer staging and better disease control, and for health service in terms of costs. Of course, our data should be increased in order to obtain more reliable and reproducible results

Assessment of the 3-dimensional left ventricular apex path with a magnetic tracking system

The Left Ventricular Apex (LVA) represents a significant site for the study of cardiac kinematics. The assessment of LVA movements throughout the cardiac cycle could be useful for evaluating the state of health of the heart. We propose a method based on a real-time 3D magnetic tracking system, for the analysis of LVA movements relatively to a static Cartesian frame of reference in order to evaluate cardiac global kinematics. An adult female sheep was used for the study. Left Ventricular Pressure (LVP) was acquired with a pressure catheter inserted in the left ventricle and used to derive the hemodynamic index of cardiac contractility (LVdP/dtMAX). LVA kinematics was assessed by using a real-time 3D magnetic tracking system (microBIRD, Ascension Technology Corp.), whose receiving sensor was epicardially glued on the exposed LVA. Acquired x, y, z coordinates described LVA displacement defined as 3-Dimensional Apex Path (3DAP). Two indexes were calculated: the Path Length (3DAPL) and the Path Volume (3DAPV), length of 3DAP and volume containing 3DAP, respectively. Data were collected during baseline condition and acute ischemia, experimentally induced by coronary artery ligation. During acute ischemia, the trend of the LVdP/dtMAX was opposite to those of 3DAPL and 3DAPV: a decrease of LVdP/dtMAX values from 876\ub13 mmHg/s (baseline) to 552\ub110 mmHg/s (ischemia) occurred, while an increase of 3DAPL and 3DAPV was observed, from 33.0\ub11.0 mm (baseline) to 41.1\ub10.7 mm (ischemia), from 4319\ub1281 mm3(baseline) to 10872\ub1468 mm3 (ischemia), respectively. Results suggest the existence of a link between cardiac efficiency and LVA kinematics: in the impaired heart, 3DAPL and 3DAPV values are greater than during baseline, because of abnormal apex movements. However, this altered kinematics seems to waste energy, as showed by the drop in the cardiac hemodynamic function (LVdP/dtMAX). The new 3DAPL and 3DAPV appeared to be valid indexes of global cardiac function. Further investigation is required to confirm these preliminary results