First operation in SPIDER and the path to complete MITICA.

The requirements of ITER neutral beam injectors (1 MeV, 40 A negative deuterium ion current for 1 h) have never been simultaneously attained; therefore, a dedicated Neutral Beam Test Facility (NBTF) was set up at Consorzio RFX (Padova, Italy). The NBTF includes two experiments: SPIDER (Source for the Production of Ions of Deuterium Extracted from Rf plasma), the full-scale prototype of the source of ITER injectors, with a 100 keV accelerator, to investigate and optimize the properties of the ion source; and MITICA, the full-scale prototype of the entire injector, devoted to the issues related to the accelerator, including voltage holding at low gas pressure. The present paper gives an account of the status of the procurements, of the timeline, and of the voltage holding tests and experiments for MITICA. As for SPIDER, the first year of operation is described, regarding the solution of some issues connected with the radiofrequency power, the source operation, and the characterization of the first negative ion beam.

Final design of the beam source for the MITICA injector.

The megavolt ITER injector and concept advancement experiment is the prototype and the test bed of the ITER heating and current drive neutral beam injectors, currently in the final design phase, in view of the installation in Padova Research on Injector Megavolt Accelerated facility in Padova, Italy. The beam source is the key component of the system, as its goal is the generation of the 1 MeV accelerated beam of deuterium or hydrogen negative ions. This paper presents the highlights of the latest developments for the finalization of the MITICA beam source design, together with a description of the most recent analyses and R&D activities carried out in support of the design.

Steady state thermal-hydraulic analyses of the MITICA cooling circuits.

Megavolt ITER Injector Concept Advancement is the full scale prototype of the heating and current drive neutral beam injectors for ITER, to be built at Consorzio RFX (Padova). The engineering design of its components is challenging: the total heat loads they will be subjected to (expected between 2 and 19 MW), the high heat fluxes (up to 20 MW/m(2)), and the beam pulse duration up to 1 h, set demanding requirements for reliable active cooling circuits. In support of the design, the thermo-hydraulic behavior of each cooling circuit under steady state condition has been investigated by using one-dimensional models. The final results, obtained considering a number of optimizations for the cooling circuits, show that all the requirements in terms of flow rate, temperature, and pressure drop are properly fulfilled.

Comparative study of beam losses and heat loads reduction methods in MITICA beam source.

In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

Non-ideal operating conditions of the ion source prototype for the ITER neutral beam injector due to thermal deformation of the support structure.

The beam formation and acceleration of the ITER neutral beam injector will be studied in the full-scale ion source, Source for Production of Ions of Deuterium Extracted from a RF plasma (SPIDER). It will be able to sustain 40 A deuterium ion beam during 1-h pulses. The operating conditions of its multi-aperture electrodes will diverge from ideality, as a consequence of inhomogeneous heating and thermally induced deformations in the support structure of the extraction and acceleration grids, which operate at different temperatures. Meeting the requirements on the aperture alignment and distance between the grids with such a large number of apertures (1280) and the huge support structures constitute a challenge. Examination of the structure thermal deformation in transient and steady conditions has been carried out, evaluating their effect on the beam performance: the paper describes the analyses and the solutions proposed to mitigate detrimental effects.

Concepts for the magnetic design of the MITICA neutral beam test facility ion accelerator.

The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.

Progress in the MITICA beam source design.

In the framework of the development of the ITER neutral beam (NB) system, a test facility is planned to be built in Padova. A full size prototype of the ITER heating NB injector (MITICA) shall be built and tested at full beam power (17 MW) as per ITER requirements. The design of the MITICA beam source has further progressed following updated optimization and overall integration criteria. In the paper, the major design choices and revisions are presented, together with some results of numerical analyses carried out in order to assess the electrostatic and thermo-mechanical behaviour of the source.

Ultrasound-guided renal biopsy: experience using an automated core biopsy system.

OBJECTIVE: To assess the safety and efficacy of ultrasound-guided percutaneous renal biopsy using an automated core biopsy system, and to determine radiologists' accuracy in predicting sample adequacy. METHODS: Ninety-five biopsies were performed on 25 native kidneys and 70 renal allografts using a 16-gauge automated, spring-loaded core biopsy device under real-time sonographic guidance. Radiologists performing the biopsy estimated the number of core samples needed to obtain an adequate specimen, based on visual inspection of each core. The final determination of the number of samples was made by a pathology technologist who attended each biopsy, based on preliminary microscopic examination of tissue cores. After each biopsy, an ultrasonographic examination was performed to search for biopsy-related hemorrhage, and a questionnaire was given to the patient to determine biopsy-related complications, which were categorized as either minor or major. RESULTS: The main indication for biopsy was acute renal failure (in 43.2% of biopsies). An average of 3 tissue cores per biopsy were obtained. Of the 94 patients in whom a biopsy was conducted to exclude diffuse renal disease, a mean of 12.5 glomeruli were present in each specimen. Overall, adequate tissue for diagnosis was obtained in 98.9% of cases. The radiologists' estimate of the number of core samples needed concurred with the pathology technologists' determination of sample adequacy in 88.4% of cases. A total of 26 complications occurred (in 27.4% of biopsies), consisting of 23 minor (24.2%) and 3 major (3.2%) complications. CONCLUSIONS: Real-time sonographic guidance in conjunction with an automated core biopsy system is a safe and accurate method of performing percutaneous renal biopsy. Routine use of sonographic examinations to search for biopsy-related complications is not indicated. Radiologists are accurate in estimating sample adequacy in most cases; however, the presence of a pathology technologist at the biopsy procedure virtually eliminates the possibility of obtaining insufficient tissue for histologic diagnosis.

Adrenal pheochromocytoma mimicking small cell carcinoma on fine needle aspiration biopsy. A case report.

BACKGROUND: Fine needle aspiration biopsy (FNAB) is a sensitive and specific technique in the diagnosis of adrenal tumors. However, in rare cases the cytomorphologic features may mimic small cell neoplasms. CASE: A 54-year-old male presented with a history of hypertension and left flank pain of recent onset. Abdominal computed tomography (CT) showed a 4-cm mass involving the left adrenal gland. Fine needle aspiration biopsy (FNAB) showed groups of small round cells with hyperchromatic nuclei. The findings were highly suspicious for metastatic small cell carcinoma. Subsequently it was learned that the mass had been noted three years earlier on CT studies but had grown from 2.5 to 4 cm. A chest radiograph was unremarkable. The clinical findings were more in keeping with a primary adrenal tumor. Immunohistochemical staining done retrospectively on the cell block showed positive reactivity for chromogranin and neuron-specific enolase. These findings, correlated with the clinical features, were in keeping with a diagnosis of pheochromocytoma. Left adrenalectomy revealed a pheochromocytoma. CONCLUSION: Adrenal pheochromocytoma should be included in the differential diagnosis of small round cell neoplasms seen on FNAB of the adrenal gland. Immunohistochemistry and clinical findings are helpful in reaching the correct diagnosis.

Comparison of real-time ultrasonography and coronal computed tomography in the diagnosis of orbital fractures.

Real-time ultrasonography (US) was used to evaluate the bony orbit in 19 patients who had sustained orbital trauma. The ability of US to demonstrate clinically significant orbital fractures was compared with that of thin-section coronal computed tomography (CT); the latter method was treated as definitive. US had a sensitivity of 92%, a specificity of 100% and a positive predictive value of 100%. Quantification of the size of fragments by the two methods yielded similar results. Real-time US adequately displayed the anatomic features of the orbit and detected clinically significant fractures. This technique may have a role in post-traumatic imaging of the orbit when coronal CT is not possible.

The role of orbital ultrasound in the diagnosis of orbital fractures.

The role of CT scanning in the diagnosis and management of craniomaxillofacial injuries is well documented. However, coexistent injuries, limitations on patient positioning, CT availability, or financial constraints may prevent or delay the diagnosis of significant orbital wall defects. Real-time ultrasound represents a safe, inexpensive, noninvasive, portable, and readily available diagnostic modality which has had a limited application in the diagnosis of orbital pathology. The objectives of this study were to define the role of orbital ultrasound in the assessment of the traumatized orbit and to provide correlation of pathology with CT imaging. Eighteen patients (16 males, 2 females) having sustained trauma to the orbitozygomatic region were assessed at a regional trauma center over a 6-month period. Each patient underwent an ultrasound examination of both orbits. Confirmatory CT scans (5-mm axial and 1.5-mm coronal orbital cuts) were then obtained for comparative assessment. Patients with open globe injuries, alteration of visual acuity, or life-threatening conditions were excluded from the study. The results of the study revealed a positive correlation between the ultrasound and CT findings in 17 (94 percent) of the patients. Ultrasound demonstrated satisfactory sensitivity (92 percent) and specificity (100 percent) and positive predictive value (100 percent) when compared with CT scanning. Soft-tissue herniation, orbital emphysema, and muscle entrapment were well visualized by means of real-time ultrasound. It is concluded that orbital ultrasound is an accurate diagnostic modality in the investigation of orbital trauma and correlates well with CT findings. A cost analysis will be presented, and details of the limitations and efficacy of orbital ultrasound will be discussed.

Medical audit of mammography: a simplified alternative.

Assessing radiologists' mammographic interpretation and performing a complete audit of a mammographic practice are notoriously difficult and time consuming. The authors propose a simplified method for accomplishing a satisfactory medical audit. A search of the 1987 pathological reports of St. Michael's Hospital in Toronto yielded 153 patients who underwent excisional biopsy of the breast and for whom preoperatively obtained mammograms were available. The medical records of the patients were reviewed to obtain demographic data, as well as information as to whether the excised lesions had been palpable and the stage of the tumour. The mammograms of the patients were categorized retrospectively by four independent observers. The findings were correlated with the results of the pathological examinations and analysed with receiver-operating characteristic (ROC) curves. Forty-five nonpalpable and 121 palpable lesions were identified, of which 70 were malignant and 96 benign. The positive predictive value of mammography for the nonpalpable lesions was 20%. Three of the 9 nonpalpable cancers and 35 of the 56 palpable ones had metastasized to the axillary lymph nodes. The area under the ROC curves for the four radiologists ranged from 0.84 to 0.89. This audit method in inexpensive and easily applied.

Role of MRI bone marrow imaging in recurrent lymphoma.

Infiltration by Hodgkin disease of the bone marrow of a thoracic vertebral body in a symptomatic patient was identified by magnetic resonance imaging, but not by radiography, radionuclide bone scanning, or computed tomography. The discovery of disease at this site substantially altered subsequent therapy.