Simulation study of a simultaneous beta-gamma-ray detection using a 3-layer phoswich detector and Monte Carlo methods.

Combination of two or three dissimilar scintillator materials as a radiation detector has found major role in environmental radiation monitoring. In this paper, a three-layer Phoswich detector including BC-400, YAG, and CsI was designed to efficiently discriminate gamma-ray in the beta events up to 3.2 MeV using a simple rise-time discrimination method. MCNPX Monte Carlo code was used to obtain interaction probability of beta and gamma-rays as well as optimum thicknesses of the layers in the designing process. The optical transport of the system was simulated by GEANT4. In this regard, the pulses from simultaneous beta-gamma emitter sources were detected and discriminated based on pulse's rise-time so that the minimum number of gamma-ray contaminating events was observed in the beta spectrum. The results showed that using the proposed configuration and the method, output pulses with a rise-time shorter than 9 ns have been successfully detected as a beta particle while those with rising time longer than 15 ns have been identified as gamma-ray events. Overall results revealed that using the proposed system, an individual spectrum of beta particles or gamma-rays can be recorded from a simultaneous beta-gamma emitter source that minimizes contribution of the other radiation.

Assessment of a low-cost commercial CCD for use in X-ray imaging.

Charged coupled device (CCD) is an imaging sensor that can be used as a digital radiation position-sensitive detector in space applications, industrial and medical imaging, etc. Commonly, the CCDs used for X-ray imaging are expensive and needed more complicated control, electronic boards. In this work, a simple and low-cost commercial CCD model (TCD1304AP) has been used to implement X-ray imaging. Moreover, a CsI(Tl) scintillation crystal with different thicknesses of 2 and 5 mm has been utilized as an X-ray to light photon converter. The driving and data acquisition boards have been designed in straightforward implementation, which can be easily performed. Also, the appropriate integration times have been set to 10 ms and 420 ms for use in cases with and without scintillation crystals respectively. The results show that this sensor has an admissible response to X-ray imaging. There is about a below 8.3% relative difference between the actual and attained dimensions from images at the direct method. However, this difference increases up to 17.7% for the indirect method due to the optical propagation in the scintillator. Furthermore, the experiment for the determination of the PSF distribution indicates that the spatial resolution of this X-ray imaging is 2% in the direct method and 3% with a 2 mm CsI(Tl) scintillator.

Variation between hospitals in outcomes following cardiac surgery in the UK.

INTRODUCTION: We examine the influence of variations in provision of cardiac surgery in the UK at hospital level on patient outcomes and also to assess whether there is an inequality of access and delivery of healthcare. Cardiothoracic surgery has pioneered the reporting of surgeon-specific outcomes, which other specialties have followed. We set out to identify factors other than the individual surgeon, which can affect outcomes and enable other surgical specialties to adopt a similar model. MATERIALS AND METHODS: A retrospective analysis of prospectively collected data of patient and hospital level factors between 2013 and 2016 from 16 cardiac surgical units in the UK were analysed through the Society for Cardiothoracic Surgery of Great Britain and Ireland and the Royal College of Surgeons Research Collaborative. Patient demographic data, risks factors, postoperative complications and in-hospital mortality, as well as hospital-level factors such as number of beds and operating theatres, were collected. Correlation between outcome measures was assessed using Pearson's correlation coefficient. Associations between hospital-level factors and outcomes were assessed using univariable and multivariable regression models. RESULTS: Of 50,871 patients (60.5% of UK caseload), 25% were older than 75 years and 29% were female. There was considerable variation between units in patient comorbidities, bed distribution and staffing. All hospitals had dedicated cardiothoracic intensive care beds and consultants. Median survival was 97.9% (range 96.3-98.6%). Postoperative complications included re-sternotomy for bleeding (median 4.8%; range 3.5-6.9%) and mediastinitis (0.4%; 0.1-1.0%), transient ischaemic attack/cerebrovascular accident (1.7%; range 0.3-3.0%), haemofiltration (3.7%; range 0.8-6.8%), intra-aortic balloon pump use (3.3%; range 0.4-7.4%), tracheostomy (1.6%; range 1.3-2.6%) and laparotomy (0.3%; range 0.2-0.6%). There was variation in outcomes between hospitals. Univariable analysis showed a small number of positive associations between hospital-level factors and outcomes but none remained significant in multivariable models. CONCLUSIONS: Variations among hospital level factors exists in both delivery of, and outcomes, following cardiac surgery in the UK. However, there was no clear association between these factors and patient outcomes. This negative finding could be explained by differences in outcome definition, differences in risk factors between centres that are not captured by standard risk stratification scores or individual surgeon/team performance.

Hardware image assessment for wireless endoscopy capsules.

Wireless capsule endoscopy is a new technology in the realm of telemedicine that has many advantages over the traditional endoscopy systems. Transmitted images should help diagnosis of diseases of the gastrointestinal tract. Two important technical challenges for the manufacturers of these capsules are power consumption and size of the circuitry. Also, the system must be fast enough for real-time processing of image or video data. To solve this problem, many hardware designs have been proposed for implementation of the image processing unit. In this paper we propose an architecture that could be used for the assessment of endoscopy images. The assessment allows avoidance of transmission of medically useless images. Hence, volume of data is reduced for more efficient transmission of images by the endoscopy capsule. This is done by color space conversion and moment calculation of images captured by the capsule. The inputs of the proposed architecture are RGB image frames and the outputs are images with converted colors and calculated image moments. Experimental results indicate that the proposed architecture has low complexity and is appropriate for a real-time application.

Major cardiothoracic trauma: Eleven-year review of outcomes in the North West of England.

INTRODUCTION: Up to 15% of patients with cardiothoracic trauma require emergency surgery, and death can be prevented in a substantial proportion of this group. UK reports have emphasised the need for improvement in this field. We assessed major cardiothoracic trauma (MCT) outcomes in North West England over 11 years. METHODS: The database from the Trauma Audit and Research Network was used to retrieve data for all patients who had suffered MCT between 2000 and 2011 in North West England and the findings analysed. Trauma that led to thoracotomy/thoracoscopy or sternotomy was defined as MCT. RESULTS: A total of 146 patients were identified, and a considerable male predominance (88.4%) noted. A total of 54.1% had sustained penetrating cardiothoracic trauma. Also, 53.4% had been admitted to tertiary-care hospitals for trauma (TCHT) and 46.6% had been admitted to non-TCHT. Overall prevalence of mortality was 35.6%. No significant difference was found in mortality between TCHT vs non-TCHT. Prevalence of mortality was significantly higher in the subgroup of patients cared for exclusively in non-TCHT compared with patients transferred from non-TCHT to TCHT (41% vs 13.8%, p<0.05). CONCLUSIONS: No significant difference was demonstrated in length of stay in hospital/length of stay in the intensive treatment unit and prevalence of mortality between patients originally presenting in TCHT and those presenting in non-TCHT. However, patients transferred from non-TCHT to TCHT had a lower prevalence of mortality. These findings may constitute a valuable benchmark for comparison with results arising after introduction of trauma centres in the UK.

Advanced bifurcation systems mother-daughter platform, a novelsystem in treatment of coronary bifurcation lesions: preliminaryresults of the prospective, multicentre first-in-man experience

Current techniques employing cylindrical and dedicated bifurcation stentsystems are limited. The ABS Modular Bifurcation System is a novel platformdesigned for automatic orientation and alignment of main branch and side branchstents with complete coverage of carina and side-branch access in a simpleintuitive procedure. This first-in-human implant study aims to provide preliminaryevidence of feasibility and short-term efficacy.Methods and results: Patients with de novo bifurcation lesions were enrolled inthis pilot, non-randomised, multi-center trial evaluating the safety, technicalfeasibility, and acute efficacy of the ABS Platform. Preliminarily results areavailable for 10 patients to date. The ABS full bifurcation stenting system (MD-BI)was deployed in the following bifurcations (7 so far): LAD- Diag (n=2), LCx-OM(n=3), and PDA-PLB (n=2) (Fig. 3). The provisional system (MD-P) has beendeployed in 3 patients so far. All lesions were Medina 1, 1, 1. Average patient agewas 55. Delivery rate and procedural success was 100%, and there was noresidual stenosis by IVUS, which revealed good stent apposition with completecoverage of the vessel carina. The 30-day composite MACE (death, MI, andtarget vessel revascularisation) was 0%. 6 month composite MACE as well asTVR has remained 0%. All patients are free of angina. Aniographic follow-up todate has been completed in 4 patients and has revealed edge re-stenosis in 2side-branch vessels only. The carina has remained widely patent with no evidenceof re-stenosis.Conclusions: The ABS Bifurcation Stent Delivery System is a novel stentplatform designed to reproducibly permit stenting in bifurcation lesions regardlessof branch angulation in a short, simple and intuitive procedure. This first-in-humanimplant study provides preliminary evidence of feasibility and short-term efficacy.

Cognitive factors related to childbirth and their effect on women's delivery preference: a comparison between a private and public hospital in Tehran.

This cross-sectional study compared cognitive-related variables for caesarean delivery in a private and public hospital in Tehran and assessed their association with maternal preference for delivery mode. A sample of 300 pregnant women in their final trimester of uncomplicated pregnancy was recruited from 1 private and 1 public hospital. They completed the Fear of Pain, Childbirth Attitude and the Pain Catastrophizing Scale questionnaires, and their sociodemographic data and delivery preference were recorded. Maternal preference for caesarean delivery was significantly higher in women in the private hospital, and they were significantly more likely to fear pain and childbirth than those in the public hospital; however, both were equally likely to catastrophize in painful situations. Women's preference for caesarean delivery in both hospitals was significantly associated with all the cognitive factors. Other factors are likely to contribute to the difference in caesarean delivery in the private and public hospital.

Introducing music as a means of habilitation for children with cochlear implants.

OBJECTIVE: To investigate the feasibility, methods and the primary results of utilizing music as a means of habilitation of children with cochlear implant. STUDY DESIGN: A habilitation program based on music training is developed. The results are presented as a case-series. METHODS: Music Training Program is introduced as a new habilitation program. Methods of training (based on Orff method) and measuring the outcomes are introduced in this paper. Effects of this program on other habilitation programs and overall hearing related skills of children were also investigated by open questioning of the parents and the habilitation staff. RESULTS: Twenty-three children, (age: 2.5-12.5 years) were selected. All children showed appreciable progress in playing a musical instrument. The effects on other habilitation processes were significant and all parents expressed their satisfaction with the program, as they perceived its benefits. DISCUSSION: The necessity of adding Music Training Program to the routine habilitation may be summarized as follows: Music is a feature of sound, which should be mastered. The psychological effects of being able to accomplish a hearing-related task can add to the self-esteem of children and help prevent and reduce anxiety. Music is a habilitation method: Introducing new concepts of sound, like temporal and frequency-related characteristics, is a crucial part of the habilitation of a child with cochlear implant. Practising new concepts needs motivation, too. We emphasize on using all means of rehabilitation and encourage teaching music to cochlear implant children between 4 and 5 years of age having approximately 4 months of experience with cochlear implant.

Clinical experience with open renal cryoablation.

OBJECTIVES: To evaluate the safety and efficacy of open renal cryoablation of small solid renal masses, since the delivery of freezing temperatures has been shown to effectively ablate solid neoplasms of the liver, uterus, and prostate. METHODS: A total of 29 patients were treated with open renal cryoablation since December 1996 and followed up to evaluate the treatment safety and initial radiographic response. RESULTS: The median preoperative lesion size was 2.2 cm, with 22 solid renal masses and 7 complex renal lesions. Five serious adverse events occurred in 5 patients, with only one event directly related to the procedure. One patient experienced a biopsy-proven local recurrence, and 91.3% of patients (median follow-up 16 months) demonstrated a complete radiographic response with only a residual scar or small, nonenhancing cyst. CONCLUSIONS: Open renal cryoablation appears to be a safe technique for the in situ destruction of solid or complex renal masses. However, inadequate freezing of renal cell carcinoma may result in local disease persistence. The expected slow growth rate of small renal cancers necessitates prolonged radiologic follow-up. Continued clinical research is required before renal cryoablation can be considered an acceptable curative treatment for renal cancer.

Testicular cysts: management and literature review.

Simple testicular cysts are extremely rare; only 20 cases have been reported in the literature. Sites include the tunica albuginea, tunica vaginalis, and testicular epidermis. Conservative enucleation is an effective treatment for these lesions once ultrasound examination establishes that the mass is cystic. Such Enucleation salvages testicular tissue. In the cases discussed, two patients were initially evaluated for vague testicular discomfort and one patient for male infertility. All were subsequently found to have benign testicular cysts. All the cysts were excised, and all patients remain disease-free. Included is a case series report of simple testicular cysts and a review of the literature.

Reassessing the role of urodynamics after cerebrovascular accident. Males versus females.

BACKGROUND AND PURPOSE: To determine whether there is a gender difference in the need for urodynamics in the evaluation of urinary incontinence after cerebrovascular accident (CVA). MATERIALS AND METHODS: We studied 72 consecutive post-CVA patients with new onset urinary incontinence documented by the patients or the persons who looked after them. Patients were evaluated between 4 and 6 weeks after their CVA and all had negative urine cultures and a postvoid residual urine determination. Exclusion criteria included narrow angle glaucoma, postvoid residual urine greater than 100 cm3 and radiographic evidence for a brainstem infarct. This left 30 male (mean age 65) and 30 female (mean age 67) patients evaluable. Patients were empirically started on anticholinergic medications and timed voids for 4 weeks after which cytoscopy and cystometry were performed. RESULTS: 28/30 females (93%) reported subjective improvement in their continence with conservative measures. 1 (3%) was found to have a urethral diverticulum, and 1 (3%) had uninhibited detrusor contractions that did not improve with medications. In the male group, 20/30 (67%) reported subjective improvement, 5 (17%) developed elevated postvoid residual urine volumes, 3 (10%) were diagnosed with urethral strictures, 1 (3%) had a bladder neck contracture, and 1 (3%) had transitional cell carcinoma in situ in the bladder. CONCLUSION: In the patient with new onset urinary incontinence in the initial period after CVA, an empiric trial of anticholinergic medications and timed voiding may be warranted in a select population of female patients without urodynamic testing or cystoscopy. This conservative approach may not be appropriate in males because of their increased likelihood of having secondary urologic conditions.

Implantation and recovery of temporary metallic stents in canine coronary arteries.

OBJECTIVES: The purpose of this study was to test the feasibility of implanting and retrieving a heat-activated recoverable temporary stent and to determine its effect on the angiographic, gross and histologic appearance of a normal coronary artery wall. BACKGROUND: Permanent coronary stenting is associated with a significant incidence of thrombosis, bleeding and vascular complications. These may be avoided by temporarily stenting for a period of hours to several days. METHODS: Seventy-eight stents constructed from the shape-memory nickel-titanium alloy nitinol were deployed by balloon expansion in the coronary arteries of 28 dogs and left in place for up to 6 months. Thirty minutes to 1 week after implantation, 70 stents were recovered by flushing the coronary arteries with 3 to 5 ml of 75 degrees C lactated Ringer solution, with collapse of the stent over a recovery catheter and subsequent withdrawal. RESULTS: All stents were successfully recovered and removed percutaneously. Mean vessel diameter after stenting was 12 +/- 6% (p < 0.05) greater than baseline diameter. Mean vessel diameter after stent removal remained enlarged (6 +/- 3%, p < 0.05). No angiographic or gross evidence of thrombosis, dissection, embolization, migration or spasm was associated with implantation or recovery. Microscopic examination revealed minor intimal injury in 40 segments (51%). Microscopic focal medial necrosis was associated with mural platelet-fibrin thrombus in 23 stented segments (29%) and media was interrupted in 7 (9%). CONCLUSIONS: This study demonstrates the feasibility of a new method of temporary stenting that uses the thermoelastic properties of nitinol to permit reliable recovery of the stent in normal canine coronary arteries.

Regulation of insulin-like growth factor-I and its receptor in rat aorta after balloon denudation. Evidence for local bioactivity.

Local production of growth factors may play a major role in vascular repair after injury. We examined the regulation of insulin-like growth factor-I (IGF-I) and its specific membrane receptor in balloon-denuded rat aorta. Aortic IGF-I mRNA and radioimmunoassayable IGF-I content increased severalfold after balloon denudation with a peak at 7 d after injury. This coincided with a reciprocal 25% decrease in IGF-I receptor mRNA content and a 40% decrease in total 125I-IGF-I binding. Scatchard analysis indicated a single class of binding sites, with a decrease in receptor number at 7 d compared to control and no change in affinity. By in situ hybridization the predominant site of IGF-I expression in the normal and the denuded vessel wall was the medial smooth muscle cell. After denudation there was a relative decrease in IGF-I receptor mRNA in the medial cells as compared to the neointima, suggesting that the site of IGF-I action was predominantly in the medial layer. These data suggest that local expression and action of IGF-I are significant in the promotion of smooth muscle cell proliferation after arterial injury.

Effects of hypophysectomy on vascular insulin-like growth factor-I gene expression after balloon denudation in rats.

Insulin-like growth factor-I (IGF-I) is a widely distributed mediator of the growth promoting effects of growth hormone (GH). We sought to determine whether the relationship between GH and IGF-I extends to the vascular system, where IGF-I is proposed to participate in the process of neointimal proliferation after balloon denudation. We show that in hypophysectomized rats basal aortic IGF-I mRNA is one-tenth that of normal rats and is increased after balloon denudation. The induction peaks at 7 days after balloon denudation at about 10-fold control levels, similar to normal rats. Treatment with GH restores basal IGF-I mRNA content to approximately half that of normal rats, without further increase in the relative magnitude of induction after balloon denudation. This local induction of IGF-I gene expression in the vessel wall following injury might explain why neointimal proliferation is not inhibited more profoundly after hypophysectomy.