Direct Determination of Fission-Barrier Heights Using Light-Ion Transfer in Inverse Kinematics.

We demonstrate a new technique for obtaining fission data for nuclei away from ß stability. These types of data are pertinent to the astrophysical r process, crucial to a complete understanding of the origin of the heavy elements, and for developing a predictive model of fission. These data are also important considerations for terrestrial applications related to power generation and safeguarding. Experimentally, such data are scarce due to the difficulties in producing the actinide targets of interest. The solenoidal-spectrometer technique, commonly used to study nucleon-transfer reactions in inverse kinematics, has been applied to the case of transfer-induced fission as a means to deduce the fission-barrier height, among other variables. The fission-barrier height of ^{239}U has been determined via the ^{238}U(d,pf) reaction in inverse kinematics, the results of which are consistent with existing neutron-induced fission data indicating the validity of the technique.

Quenching of Single-Particle Strength in A=15 Nuclei.

Absolute cross sections for the addition of s- and d-wave neutrons to ^{14}C and ^{14}N have been determined simultaneously via the (d,p) reaction at 10 MeV/u. The difference between the neutron and proton separation energies, ΔS, is around -20 MeV for the ^{14}C+n system and +8 MeV for ^{14}N+n. The population of the 1s_{1/2} and 0d_{5/2} orbitals for both systems is reduced by a factor of approximately 0.5 compared with the independent single-particle model, or about 0.6 when compared with the shell model. This finding strongly contrasts with results deduced from intermediate-energy knockout reactions between similar nuclei on targets of ^{9}Be and ^{12}C. The simultaneous technique used removes many systematic uncertainties.

First Exploration of Neutron Shell Structure below Lead and beyond N=126.

The nuclei below lead but with more than 126 neutrons are crucial to an understanding of the astrophysical r process in producing nuclei heavier than A∼190. Despite their importance, the structure and properties of these nuclei remain experimentally untested as they are difficult to produce in nuclear reactions with stable beams. In a first exploration of the shell structure of this region, neutron excitations in ^{207}Hg have been probed using the neutron-adding (d,p) reaction in inverse kinematics. The radioactive beam of ^{206}Hg was delivered to the new ISOLDE Solenoidal Spectrometer at an energy above the Coulomb barrier. The spectroscopy of ^{207}Hg marks a first step in improving our understanding of the relevant structural properties of nuclei involved in a key part of the path of the r process.

A multicentre assessment of prostate MRI quality and compliance with UK and international standards.

AIM: To assess prostate magnetic resonance imaging (MRI) image quality and compliance with technical standards between centres in the South West region of the UK. MATERIALS AND METHODS: Fifteen imaging sites in the region submitted seven consecutive anonymised MRI studies. These were assessed by two experienced radiologists in consensus. Overall, subjective image quality for T2-weighted imaging (T2W), diffusion weighted imaging (DWI), and dynamic contrast enhancement (DCE) was scored on a five-point Likert scale. Five additional quality parameters were also assessed visually, including image noise, motion, artefact, and distortion. The degree of compliance by each site with 21 published technical standards was also assessed. RESULTS: Ninety-four MRI examinations were reviewed from across all sites (mean 6.3 scans per site, range 5-7). Mean compliance with technical standards was 63% (range 38-86%). Forty-seven percent of sites did not perform DCE. One site used a 3 T scanner. The percentage of patients with overall quality scores of ≥3 (diagnostically acceptable) were 68% for T2W, 81% for DWI, and 60% for both T2W and DWI. Ninety-three percent of the 45 patients who underwent DCE had diagnostically acceptable studies. By scanner age, the percentage of patients with diagnostically acceptable T2W scores was 53% for scanners ≥7 years and 80% when <7 years (p=0.006). Comparing individual sites, the mean overall quality scores were 2.9 (range 2.2-4.2) for T2W, 3.2 (1.8-4.7) for DWI, and 3.4 (2.5-4.7) for DCE. CONCLUSION: There is wide variation in compliance with recognised technical standards and image quality across sites. If MRI is to replace biopsy in selected low-risk patients, improvements in image quality may be required.

The integration of transabdominal ultrasound simulators into an ultrasound curriculum.

INTRODUCTION: Simulation is increasingly used throughout medicine. Within ultrasound, simulators are more established for learning transvaginal and interventional procedures. The use of modern high-fidelity transabdominal simulators is increasing, particularly in centres with large trainee numbers. There is no current literature on the value of these simulators in gaining competence in abdominal ultrasound. The aim was to investigate the impact of a new ultrasound curriculum, incorporating transabdominal simulators into the first year of training in a UK radiology academy. METHODS: The simulator group included 13 trainees. The preceding cohort of 15 trainees was the control group. After 10 months, a clinical assessment was performed to assess whether the new curriculum resulted in improved ultrasound skills. Questionnaires were designed to explore the acceptability of simulation training and whether it had any impact on confidence levels. RESULTS: Trainees who had received simulator-enriched training scored higher in an objective clinical ultrasound assessment, which was statistically significant (p = 0.0463). End confidence scores for obtaining diagnostic images and demonstrating pathology were also higher in the simulation group. All trainees stated that transabdominal simulator training was useful in early training. CONCLUSIONS: This initial study shows that embedded into a curriculum, transabdominal ultrasound simulators are an acceptable training method that can result in improved ultrasound skills and higher confidence levels. Using simulators early in training could allow trainees to master the basics, improve their confidence, enabling them to get more educational value from clinical ultrasound experience while reducing the impact of training on service provision.

Shape coexistence in the neutron-deficient even-even (182-188)Hg isotopes studied via coulomb excitation.

Coulomb-excitation experiments to study electromagnetic properties of radioactive even-even Hg isotopes were performed with 2.85 MeV/nucleon mercury beams from REX-ISOLDE. Magnitudes and relative signs of the reduced E2 matrix elements that couple the ground state and low-lying excited states in Hg182-188 were extracted. Information on the deformation of the ground and the first excited 0+ states was deduced using the quadrupole sum rules approach. Results show that the ground state is slightly deformed and of oblate nature, while a larger deformation for the excited 0+ state was noted in Hg182,184. The results are compared to beyond mean field and interacting-boson based models and interpreted within a two-state mixing model. Partial agreement with the model calculations was obtained. The presence of two different structures in the light even-mass mercury isotopes that coexist at low excitation energy is firmly established.

Single-photon emission CT using (99m)Tc-dimercaptosuccinic acid (DMSA) for characterization of suspected renal masses.

OBJECTIVE: A retrospective analysis of the clinical utility of (99m)Tc-dimercaptosuccinic acid (DMSA) single photon emission CT (SPECT) for characterization of suspected renal masses. METHODS: 15 patients who had undergone (99m)Tc-DMSA SPECT were identified, and 13 patients also had SPECT/CT. (99m)Tc-DMSA uptake in the renal lesion was characterized semiquantitatively. Other imaging tests, histology and clinical data were available for correlation. RESULTS: (99m)Tc-DMSA was not taken up in all five renal masses with histological confirmation of malignancy (uptake 7-19% of normal renal tissue); in two further masses, which were clinically likely to be malignant; and in one indeterminate mass (lack of sufficiently long follow-up). No renal malignancy was identified in any of the seven patients whose renal masses had normal (99m)Tc-DMSA uptake (41-130%). CONCLUSION: Although caution with regard to applying those results in clinical practice must be advised, owing to the retrospective nature of this report and the small number of patients included, it seems that (99m)Tc-DMSA SPECT shows a clinically useful diagnostic accuracy for distinguishing true renal masses (which in many cases require surgery) from pseudomasses. ADVANCES IN KNOWLEDGE: (99m)Tc-DMSA SPECT is a clinically useful adjunct test for characterization of suspected renal masses.

Testicular microlithiasis an ultrasound dilemma: survey of opinions regarding significance and management amongst UK ultrasound practitioners.

OBJECTIVE: To establish whether there is a consensus regarding the significance of testicular microlithiasis and a strategy for managing patients with this condition, amongst ultrasound practitioners in the UK. METHODS: An electronic questionnaire was distributed to 1482 members of the British Medical Ultrasound Society (BMUS), requesting information from ultrasound practitioners involved in scrotal ultrasound about their interpretation of the risk associated with testicular microlithiasis and their departmental or personal recommendations for managing patients with this condition. RESULTS: Responses were obtained from 221 BMUS members. Analysis demonstrated a wide variation in the significance attributed to the discovery of testicular microlithiasis and the risk of subsequent development of testicular germ cell tumours. There was also great variation in strategies for management of patients with testicular microlithiasis, including the need for surveillance ultrasound, amongst ultrasound practitioners regardless of their job description. CONCLUSION: Lack of consensus shown by this study highlights significant differences across the UK in managing patients with testicular microlithiasis and validates the importance of guidance currently being formulated by the European Society of Urogenital Radiology. ADVANCES IN KNOWLEDGE: We believe that this is the first survey to be conducted amongst imaging specialists in the UK regarding testicular microlithiasis and demonstrates that there is currently no uniform practice in managing patients with this condition.

Can ultrasound help to manage patients with scrotal trauma?

Traumatic injuries to the scrotum are uncommon but, when they do occur, frequently lead to serious complications. Early complications include testicular infarction, necrosis and abscess formation; in the longer-term trauma may result in testicular atrophy and subfertility. Early surgical intervention in patients with testicular rupture can significantly improve the clinical outcome and reduce the need for delayed orchidectomy. However, clinical examination of the scrotum following trauma is difficult and frequently inaccurate; this may result in incorrect triage of patients for surgical exploration. Scrotal ultrasound can reliably assess scrotal injuries and diagnose testicular rupture with a high level of accuracy. Additionally, ultrasound can provide important information regarding testicular perfusion, which can further inform decisions on surgical management. This article reviews the sonographic findings that may be encountered in patients with scrotal trauma, with an emphasis on blunt trauma. It describes the pivotal role that ultrasound can play in the accurate triage of these patients to surgical or conservative management.

Quenching of cross sections in nucleon transfer reactions.

Cross sections for proton knockout observed in (e,e'p) reactions are apparently quenched by a factor of ∼0.5, an effect attributed to short-range correlations between nucleons. Here we demonstrate that such quenching is not restricted to proton knockout, but a more general phenomenon associated with any nucleon transfer. Measurements of absolute cross sections on a number of targets between 16O and 208Pb were analyzed in a consistent way, with the cross sections reduced to spectroscopic factors through the distorted-wave Born approximation with global optical potentials. Across the 124 cases analyzed here, induced by various proton- and neutron-transfer reactions and with angular momentum transfer ℓ=0-7, the results are consistent with a quenching factor of 0.55. This is an apparently uniform quenching of single-particle motion in the nuclear medium. The effect is seen not only in (d,p) reactions but also in reactions with A=3 and 4 projectiles, when realistic wave functions are used for the projectiles.

Test of sum rules in nucleon transfer reactions.

The quantitative consistency of nucleon transfer reactions as a probe of the occupancy of valence orbits in nuclei is tested. Neutron-adding, neutron-removal, and proton-adding transfer reactions were measured on the four stable even Ni isotopes, with particular attention to the cross section determinations. The data were analyzed consistently in terms of the distorted wave Born approximation to yield spectroscopic factors. Valence-orbit occupancies were extracted, utilizing the Macfarlane-French sum rules. The deduced occupancies are consistent with the changing number of valence neutrons, as are the vacancies for protons, both at the level of <5%. While there has been some debate regarding the true "observability" of spectroscopic factors, the present results indicate that empirically they yield self-consistent results.

Attention-deficit/hyperactivity disorder in childhood is associated with cognitive test profiles in the geriatric population but not with mild cognitive impairment or Alzheimer's disease.

The frequency of ADHD in the aging population and its relationship to late-life cognitive decline has not been studied previously. To address this gap in our understanding, the Wender-Utah ADHD Rating scale (WURS) was administered to 310 geriatric subjects with cognitive status ranging from normal cognition to mild cognitive impairment to overt dementia. The frequency of WURS-positive ADHD in this sample was 4.4%. WURS scores were not related to cognitive diagnoses, but did show nonlinear associations with tasks requiring sustained attention. The frequency of ADHD appears stable across generations and does not appear to be associated with MCI or dementia diagnoses. The association of attentional processing deficits and WURS scores in geriatric subjects could suggest that such traits remain stable throughout life. Caution should be considered when interpreting cognitive test profiles in the aging population that exhibit signs and symptoms of ADHD, as attentional deficits may not necessarily imply the existence of an underlying neurodegenerative disease state.

Digital tomosynthesis--a new lease of life for the intravenous urogram?

OBJECTIVES: Digital tomosynthesis is a new digital technique based on conventional X-ray tomography. It acquires multiple low-dose projections during a single sweep of the X-ray tube, which are reassembled to provide high-resolution slices at different depths. Suggested uses include visualisation of pulmonary nodules, mammography, angiography, dental imaging and delineation of fractures. This study aims to evaluate its potential role as part of an intravenous urogram (IVU) by assessing the diagnostic quality in imaging the kidneys in clinical practice. METHODS: 100 renal units from consecutive traditional IVU studies were retrospectively compared with 101 renal units imaged using digital tomosynthesis. These were scored for visualisation of the renal outline and collecting system, presence of a renal cyst or mass and overall diagnostic quality. Radiation doses were calculated. RESULTS: 46.5% of traditional IVUs were found to be of diagnostic quality. The IVUs with digital tomosynthesis were of diagnostic quality in 95.5%. This represents a highly statistically significant difference (p<0.0001). There was also a statistically significant dose reduction, with a mean reduction of 56%, for the samples studied. CONCLUSION: Digital tomosynthesis offers a significant increase in the percentage of diagnostic quality tests for assessing renal pathology, compared with traditional IVU, and significantly reduces radiation. It also offers considerable advantages in ease and speed of imaging. For these reasons, in any situation where IVU is still being used to assess the kidneys, digital tomosynthesis is likely to be of considerable benefit in improving diagnostic quality.

A training simulator for ultrasound-guided percutaneous nephrostomy insertion.

Increasing trainee numbers and changes to working patterns have resulted in a scarcity of training opportunities for training-grade doctors wishing to learn nephrostomy tube insertion techniques. A method of introducing trainees to the skills required to perform percutaneous nephrostomy in a safe, non-threatening environment, without risk to patients, is desirable. Commercial and biological nephrostomy phantoms are available, but they are expensive and not widely available, and a cheap, safe, valid alternative is desirable. We describe a simple technique for producing a gelatin-based phantom, which we suggest has face and content simulator validity. The use of this nephrostomy phantom could optimise existing clinical training opportunities through familiarisation with nephrostomy technique and equipment, and development of the psychomotor skills required for successful nephrostomy insertion prior to undertaking supervised procedures on patients.

First experiment with HELIOS: the structure of 13B.

A first experiment is reported that makes use of a new kind of spectrometer uniquely suited to the study of reactions with radioactive beams in inverse kinematics, the helical orbit spectrometer, HELIOS. The properties of some low-lying states in the neutron-rich N=8 nucleus 13B were studied with good resolution. From the measured angular distributions of the (d,p) reaction and the relative spectroscopic factors, spin and configuration assignments of the first- and third-excited states of this nucleus can be constrained.

Initial clinical experience of an ultrasonic strain imaging system with novel noise-masking capability.

Quasistatic strain imaging is a form of elastography that can produce qualitative images of tissue stiffness with only software modifications to conventional ultrasound hardware. Unlike current commercial offerings, the novel strain-imaging system that is the subject of this paper displays regions of signal decorrelation using an overlaid colour mask and can also produce three-dimensional (3D) strain images. In illustrative studies of the breast, testis and thyroid, the colour mask is seen to reduce the potential to misinterpret noise as meaningful stiffness information, and also helps to differentiate cystic and solid lesions. High-quality imaging of the testis in vivo demonstrates that 3D strain imaging is feasible.

Structure of 240Pu: evidence for octupole phonon condensation?

The expanded level structure of 240Pu available from the present study highlights the role of strong octupole correlations in this nucleus. In addition to a delayed alignment in the yrast band, the observations include the presence of both I(+)-->(I-1)(-) and I(-)-->(I-1)(+)E1 transitions linking states of the yrast and negative-parity bands at high spin and the presence of an additional even-spin, positive-parity band deexciting exclusively to the negative-parity sequence. The observations appear to be consistent with expectations based on the recently proposed concept of octupole phonon condensation.

MRI appearances of acute idiopathic scrotal oedema in an adult.

Acute idiopathic scrotal oedema is an uncommon cause of acute painless scrotal swelling that is usually seen in children. Traditionally, ultrasound has been used to help establish the diagnosis in the appropriate clinical setting. We report the MRI appearances of acute idiopathic scrotal oedema in a 51-year-old male with associated involvement of the penis.

Nuclear structure relevant to neutrinoless double beta decay: 76Ge and 76Se.

The possibility of observing neutrinoless double beta decay offers the opportunity of determining the effective neutrino mass if the nuclear matrix element were known. Theoretical calculations are uncertain, and measurements of the occupations of valence orbits by nucleons active in the decay can be important. The occupation of valence neutron orbits in the ground states of 76Ge (a candidate for such decay) and 76Se (the daughter nucleus) were determined by precisely measuring cross sections for both neutron-adding and removing transfer reactions. Our results indicate that the Fermi surface is much more diffuse than in theoretical calculations. We find that the populations of at least three orbits change significantly between these two ground states while in the calculations, the changes are confined primarily to one orbit.