Improved Čerenkov counting techniques based on a free parameter model

In the past few years, two Čerenkov methods were developed to make activity measurements of high-energy beta emitters in liquid scintillation counters with two or three photomultiplier tubes (PMTs) possible. Both methods are based on a free parameter model and make use of the Frank and Tamm theory for the emission of Čerenkov light. In this article, additional effects are discussed and further improvements are presented. The dependence of the refractive index of water on the wavelength can now be taken into account, which has also an influence on the upper limit of the wavelength region for the production of Čerenkov light. In addition, the dependence of the PMT response on the wavelength is taken into account. Finally, it is possible to take a potential asymmetry of efficiencies in a system with three PMTs into account. To this end, three free parameters are assigned to each individual PMT and then determined by means of a downhill simplex optimization algorithm. The computed counting efficiencies for a triple-to-double coincidence ratio (TDCR) system were compared with experimental data for ³²P, ⁸⁹Sr, and ⁹⁰Y.     

Design and construction of a stand-alone camera system and its clinical application in nuclear medicine.

This paper reports investigations into some of the improvements of the performance of 'modular' gamma-ray cameras. Each modular camera has a 10 x 10 cm NaI(Tl) scintillation crystal and four 5 x 5 cm photomultiplier tubes (PMTs). When the gamma-ray photons interact with the crystal, scintillation flashes are emitted from the crystal and detected by the PMTs. The PMTs then convert the light flashes to current pulses. A digital computing circuitry processes the PMT outputs and assigns an estimated (x, y) coordinate corresponding to the location of interaction of each gamma-ray photon in the crystal and thus an image is formed. This paper is concerned with improvements and clinical applications of the modular cameras. We do the camera characterization by measuring spatial resolution and sensitivity of the modular camera and compare these characteristics to those of a commercial gamma camera. We design and construct a stand-alone planar imaging system based on the modular camera. This imager is examined with a set of phantoms and clinical tests to demonstrate the clinical feasibility of the stand-alone system.     

Extended Whole-body Ga-68 DOTATATE PET-CT in evaluating Tumour-Induced Osteomalacia: Case report and review of literature

Tumour-induced osteomalacia is a rare paraneoplastic syndrome that manifests as chronic hypophosphataemia, non-specific bone pain and muscle weakness. It is generally caused by phosphaturic mesenchymal tumour (PMT), which is uncommonly associated with synchronous tumours. However, diagnosis is often delayed for several years due to the rarity, indolent growing nature and non-specific symptoms of the disease, often resulting in an overlook by clinicians during assessments. The patient initially presented with hypophosphataemia and generalised skeletal pain with multiple atraumatic fractures. Blood tests revealed serum calcium levels at the upper limit and extremely low inorganic phosphate levels. Herein, we report a case where two synchronous PMTs from two different sites were detected by ‘extended’ whole-body Ga-68 DOTATATE PET-CT, leading to remission of the disease after complete surgical removal. Early detection and diagnosis of PMT neoplasm is crucial, as complete surgical resection of this tumour is the only definitive treatment currently known. Upon excision, this curable disease will result in complete resolution of symptoms and blood parameters, leading to remission of the disease which significantly improves the patient’s quality of life. PMT often over-expresses somatostatin receptors (SSTR), predominantly subtype 2A, and Ga-68 DOTATATE PET-CT is a selective SSTR imaging that targets this characteristic over-expression in these tumours. The high diagnostic accuracy of Ga-68 DOTATATE PET-CT should be the primary imaging modality for full evaluation of this disease.     

One-year follow-up evaluation of the sexually transmitted diseases/human immunodeficiency virus intervention program in a marine corps sample.

Although a substantial number of studies have been conducted to evaluate the impact of various human immunodeficiency virus (HIV) prevention programs, most of them have focused on civilian populations. There is a clear need to develop and evaluate sexually transmitted diseases (STD)/HIV prevention programs designed specifically for U.S. military populations. The objective of the present study was to determine whether a behavioral intervention known as the STD/HIV Intervention Program (SHIP) would have a sustained positive impact on the behavior of a sample of Marines. A 1-year follow-up telephone interview was administered to (1) Marines who participated in the SHIP course (intervention group), and (2) a quasi-control group of Marines who were not exposed to the SHIP course. The intervention and control groups differed significantly in the percentage of the time they had used condoms during the past year. The intervention participants reported using condoms a greater percentage of the time than the nonparticipants.     

Activity-related knee injuries and pain in athletic adolescents

By collecting data from 45 students at a ski high school, we found that a total of 73% of the students reported activity-related pain/injuries of the knee. Sixty-one percent had overuse injuries, 27% malalignment, and 12% had indistinct knee pain. Females suffered more knee pain/injuries (88%) than males (57%). Significantly higher Q-angle degrees were recorded for females (16) than for males (10). "Jumper's knee" was found in all competitive students with a KT manual maximum difference (MMD) of 3 mm or more (mean 4 mm), with a hard endpoint, whereas this was less common among the other competitive students (P < 0.05). The students were given counselling about training and physiotherapy. In the follow-up study 1 year later, a significant reduction of knee pain/overuse injuries, from 73% to 35%, was recorded. This may be related to better equipment, the development of techniques, and training of the muscles. A high volume of training and knee instability, with MMD of 3 mm or more, seemed to be correlated with an increased risk for "jumper's knee" and, possibly, for skiing injuries. By identifying those at increased risk, preseason recommendations can be made and ski injuries may be prevented.     

Radiologists as clinical tutors in a problem-based medical school curriculum.

RATIONALE AND OBJECTIVES: The authors sought to evaluate the experience of radiologists teaching in a problem-based pre-clinical medical school curriculum. MATERIALS AND METHODS: The undergraduate medical school curriculum at Wake Forest University includes 2 problem-based preclinical years that integrate basic and clinical sciences. Sixteen radiology fellows served as general clinical tutors for 5-9 weeks, each guiding the work of six 2nd-year students, often in tandem with a basic science tutor. On completion of the tutoring. the radiologists and the students were surveyed by means of a questionnaire. A follow-up group interview was conducted with the radiologists. RESULTS: The response rate to the questionnaire was 81% for the radiologists and 47% for the students. On average, radiologists spent 6.1 hours weekly on preparation and tutoring and 3.5 hours in total on administration and grading. All radiologists thought tutoring was rewarding, but seven of the 13 respondents (54%) disliked assigning grades. Radiologists spent less time teaching radiology residents and performing research, but few thought their clinical work was adversely affected. Nearly half of the radiologist-tutors thought that the preliminary orientation and training provided to them by the medical school was not adequate, and nearly all of them thought that they could have been better prepared. All of the medical students improved their perceptions of radiologists after having had a radiologist as a tutor, and most thought that the radiologist-tutors performed as well as or better than tutors from other disciplines. CONCLUSION: Radiologists can be successful as general tutors in a problem-based medical school curriculum. benefiting both radiologists and students. Better orientation and training by the medical school would improve the program.     

Social media to supplement point-of-care ultrasound courses: the “sandwich e-learning” approach. A randomized trial

Background

Point-of-care ultrasound (POC-US) is gaining importance in almost all specialties. E-learning has been used to teach theoretical knowledge and pattern recognition. As social media are universally available, they can be utilized for educational purposes. We wanted to evaluate the utility of the sandwich e-learning approach defined as a pre-course e-learning and a post-course learning activity using Facebook after a one-day point-of-care ultrasound (POC-US) course and its effect on the retention of knowledge.

Methods

A total of 62 medial students were recruited for this study and randomly assigned to one of four groups. All groups received an identical hands-on training and performed several tests during the study period. The hands-on training was performed in groups of five students per instructor with the students scanning each other. Group 1 had access to pre-course e-learning, but not to post-course e-learning. Instead of a pre-course e-learning, group 2 listened to presentations at the day of the course (classroom teaching) and had access to the post-course learning activity using Facebook. Group 3 had access to both pre- and post-course e-learning (sandwich e-learning) activities, while group 4 listened classroom presentations only (classroom teaching only). Therefore only groups 2 and 3 had access to post-course learning via Facebook by joining a secured group. Posts containing ultrasound pictures and videos were published to this group. The students were asked to “like” the posts to monitor attendance. Knowledge retention was assessed 6 weeks after the course.

Results

After 6 weeks, group 3 achieved comparable results when compared to group 2 (82.2 % + ?8.2 vs. 84.3 + ?8.02) (p = 0.3). Students who participated in the post-course activity were more satisfied with the overall course than students without post-course learning (5.5 vs. 5.3 on a range from 1 to 6).

Conclusions

In this study, the sandwich e-learning approach led to equal rates of knowledge retention compared to classroom lectures and post-course learning. Students appreciate new media for learning experiences and are more satisfied with their learning activity. The sandwich e-learning can be used to maximize hands-on training during courses.

     

Predictors of Navy attrition. II. A demonstration of potential usefulness for screening

The Sailors Health Inventory Program (SHIP) questionnaire is a medical and psychosocial history questionnaire completed by all Navy recruits. This study was an investigation of the potential usefulness of the SHIP questionnaire for screening to reduce basic training attrition. The sample consisted of 66,690 Navy recruits. Although the most valid individual SHIP items for predicting attrition tended to be psychological or behavioral in nature, a composite of 40 diverse SHIP questions (including medical questions) was found to be the best overall attrition predictor. Further analyses revealed that the 40-item composite is a considerably more powerful attrition predictor than is either educational credential or mental ability score, which together are currently the U.S. military's primary attrition management tools. Finally, the consequences of using different cutoff scores on the 40-item composite were simulated so that various hypothetical screening strategies could be considered.     

Pharmacomechanical Thrombectomy in Paget–Schroetter Syndrome

Purpose

The purpose of the study was to evaluate feasibility of pharmacomechanical thrombectomy (PMT) in the treatment of Paget–Schroetter syndrome (PSS) followed by thoracoscopic or open surgical decompression of the subclavian vein.

Methods

Twenty-two out of 27 consecutive patients with PSS received PMT using the Trellis-8 peripheral infusion system (Covidien) between 2010 and 2014. Subsequent surgery was performed in 18 of those patients, 9 patients were treated with thoracoscopic, 7 patients with subclavicular, and 2 patients with transaxillary first rib resection, 4 patients were treated with PMT and anticoagulation alone. Technical success, complications, and patency were registered.

Results

PMT was successful in 21 (95 %) patients; 1 patient with unsatisfactory lysis received further catheter-directed thrombolysis, which, however, did not improve the result. The mean endovascular procedure time was 105 ± 33 min (range 70–200 min), and the required median amount of thrombolytic agent was 500,000 international unit (IU; range 250,000–1,000,000 IU). Adjunctive balloon venoplasty and aspiration were used in 18 (82 %) and 7 (32 %) cases, respectively. One patient had an intimal tear of the subclavian vein that was discovered and repaired during surgery. There were no other complications related to the endovascular procedure. At follow-up, 18 of 21 patients (86 %) with follow-up imaging available had patent subclavian vein, and all except 1 of the 22 patients were asymptomatic. The mean follow-up time was 25 ± 17 months.

Conclusions

In experienced hands, PMT is effective for early thrombus removal in PSS. Surgical decompression must be considered after PMT.

     

Integrated medical school ultrasound: development of an ultrasound vertical curriculum

Background

Physician-performed focused ultrasonography is a rapidly growing field with numerous clinical applications. Focused ultrasound is a clinically useful tool with relevant applications across most specialties. Ultrasound technology has outpaced the education, necessitating an early introduction to the technology within the medical education system. There are many challenges to integrating ultrasound into medical education including identifying appropriately trained faculty, access to adequate resources, and appropriate integration into existing medical education curricula. As focused ultrasonography increasingly penetrates academic and community practices, access to ultrasound equipment and trained faculty is improving. However, there has remained the major challenge of determining at which level is integrating ultrasound training within the medical training paradigm most appropriate.

Methods

The Ohio State University College of Medicine has developed a novel vertical curriculum for focused ultrasonography which is concordant with the 4-year medical school curriculum. Given current evidenced-based practices, a curriculum was developed which provides medical students an exposure in focused ultrasonography. The curriculum utilizes focused ultrasonography as a teaching aid for students to gain a more thorough understanding of basic and clinical science within the medical school curriculum. The objectives of the course are to develop student understanding in indications for use, acquisition of images, interpretation of an ultrasound examination, and appropriate decision-making of ultrasound findings.

Results

Preliminary data indicate that a vertical ultrasound curriculum is a feasible and effective means of teaching focused ultrasonography. The foreseeable limitations include faculty skill level and training, initial cost of equipment, and incorporating additional information into an already saturated medical school curriculum.

Conclusions

Focused ultrasonography is an evolving concept in medicine. It has been shown to improve education and patient care. The indications for and implementation of focused ultrasound is rapidly expanding in all levels of medicine. The ideal method for teaching ultrasound has yet to be established. The vertical curriculum in ultrasound at The Ohio State University College of Medicine is a novel evidenced-based training regimen at the medical school level which integrates ultrasound training into medical education and serves as a model for future integrated ultrasound curricula.     

Educational effects on radiological technology students of programs using a simulated aged person and hemiplegia patient

A practical training program that enabled students to experience an aged person and hemiplegia patient was developed as part of the "Practice Program in Medical Imaging Technology," to help the students understand how to support patients in the X-ray examination setting. Eighty-three third-year radiological technology students participated in the program. During the hour-long course, they experienced a simulated program that contained various checkpoints. The students pointed out the difficulty patients had in going up and down stairs (51.8%) and their feelings of uneasiness and fear of blindness (36.1%). As a result of this practical training program, the students increased their understanding of how to support patients slated for X-ray examinations. However, certain problems became clear, such as students' insufficient experience and lack of practical guidance in supporting aged patients and those with hemiplegia at the time of X-ray examinations. This information will helpful for improving similar training programs to be held in the future.     

Impact of a classroom standing desk intervention on daily objectively measured sedentary behavior and physical activity in youth

Objectives

We investigated the impact of a standing desk intervention on daily objectively monitored sedentary behavior and physical activity in 6th grade school students.

Efficacy of a Modified Pharmacomechanical Thrombolysis Technique for Endovascular Treatment of Thrombosed Prosthetic Arteriovenous Grafts

Objective

We applied a modified pharmacomechanical thrombolysis (PMT) technique to endovascular treatment of thrombosed arteriovenous (AV) grafts without the use of any mechanical thrombectomy devices. The aim of this study was to evaluate the efficacy of the PMT technique in the treatment of thrombosed AV grafts by analyzing the long-term patency.

Materials and Methods

Eighty-two patients with thrombosed AV grafts were treated with the PMT technique. AV graft surveillance to detect failing/failed access was followed by endovascular treatment.

Results

The technical and clinical success rates were 95% and 95%, respectively. The total number of thrombolysis sessions was 279. A post-intervention primary patency rate was 45% and 22% at 12 and 24 months, respectively. The secondary patency rate was 96% and 91% at 12 and 24 months, respectively. No major complications were noticed.

Conclusion

The modified PMT technique is effective in endovascular treatment of thrombosed AV grafts.     

Predictors of Navy attrition. I. Analysis of 1-year attrition

First-term attrition, defined as failing to complete the contracted first enlistment term, is one of the most serious and costly problems faced by the U.S. Navy. This study was an investigation of 1-year Navy attrition in relation to demographic factors and variables assessed by the Sailors' Health Inventory Program (SHIP) questionnaire, a medical and psychosocial history questionnaire completed by all Navy recruits. Overall attrition, as well as specific categories of attrition (e.g., medical, behavioral, and administrative), were studied. The sample consisted of 66,690 Navy recruits whose status (retention vs. attrition) could be tracked to the 1-year mark. The strongest predictors of overall attrition were educational level, self-reported history of shortness of breath, ever being suspended or expelled from school, history of depression/excessive worry, fainting or dizziness, and recurrent back pain. Many other medical and psychosocial items from SHIP were also predictive of attrition. Similar factors were associated with different categories of attrition (e.g., medical, behavioral). The implications of these findings for attrition reduction strategies are discussed.     

Lessons learned from Action Schools! BC—An ‘active school’ model to promote physical activity in elementary schools

The 'active school' model offers promise for promoting school-based physical activity (PA); however, few intervention trials have evaluated its effectiveness. Thus, our purpose was to: (1) describe Action Schools! BC (AS! BC) and its implementation (fidelity and feasibility) and (2) evaluate the impact of AS! BC on school provision of PA. Ten elementary schools were randomly assigned to one of the three conditions: Usual Practice (UP, three schools), Liaison (LS, four schools) or Champion (CS, three schools). Teachers in LS and CS schools received AS! BC training and resources but differed on the level of facilitation provided. UP schools continued with regular PA. Delivery of PA during the 11-month intervention was assessed with weekly Activity Logs and intervention fidelity and feasibility were assessed using Action Plans, workshop evaluations, teacher surveys and focus groups with administrators, teachers, parents and students. Physical activity delivered was significantly greater in LS (+67.4 min/week; 95% CI: 18.7-116.1) and CS (+55.2 min/week; 95% CI: 26.4-83.9) schools than UP schools. Analysis of Action Plans and Activity Logs showed fidelity to the model and moderate levels of compliance (75%). Teachers were highly satisfied with training and support. Benefits of AS! BC included positive changes in the children and school climate, including provision of resources, improved communication and program flexibility. These results support the use of the 'active school' model to positively alter the school environment. The AS! BC model was effective, providing more opportunities for "more children to be more active more often" and as such has the potential to provide health benefits to elementary school children.     

Retaining self-determined goals and the impact on examination scores

OBJECTIVE: To determine how many students retained their own goals during a 6-month radiology course and to evaluate the impact on the final examination scores. METHODS: At the beginning of the radiology course in 2003, all first-year military nursing students (N = 60) were asked to list their self-determined goals for learning radiology. After the 6-month course, they were asked to restate their initial self-determined goals, without previous notice. The replies were classified into three groups, as follows: group 1, those who did not restate their own goals accurately; group 2, those who restated their own goals accurately; group 3, those who stated, "I don't remember." The mean examination scores for the groups were compared by using Student's t test. RESULTS: The mean score (mean +/- SD, 69.6 +/- 6.9) for students in group 3 was significantly higher than that (mean +/- SD, 61.8 +/- 5.8) for students in group 1 (p = 0.003). The mean score (mean +/- SD, 64.7 +/- 6.9) for group 2 was higher than that for group 1, but the difference was not statistically significant (p = 0.109). CONCLUSIONS: Retaining self-determined goals has clear advantages in a military nursing school. However, those who are honest and report forgetting their self-determined goals do not always achieve poor results on the examination.     

Adjunctive percutaneous mechanical thrombectomy for lower-extremity deep vein thrombosis: clinical and economic outcomes

PURPOSE: To assess the clinical and economic benefits of catheter-directed thrombolysis (CDT) alone versus CDT with rheolytic percutaneous mechanical thrombectomy (PMT) for lower-extremity deep vein thrombosis (DVT). MATERIALS AND METHODS: Consecutive patients with acute iliofemoral DVT treated with CDT with urokinase between 1997 and 2003 were identified. Demographic characteristics and clinical and economic outcomes were compared between patients treated with CDT alone versus CDT plus PMT. RESULTS: Twenty-six limbs in 23 patients received CDT with urokinase, whereas 19 limbs in 14 patients were treated with CDT plus PMT. Mean treatment duration for CDT was 56.5 +/- 27.4 hours, compared with 30.3 +/- 17.8 hours for CDT plus PMT (P = .001). Mean urokinase dose for CDT was 6.70 +/- 5.9 million U compared with 2.95 +/- 1.82 million U for CDT plus PMT (P = .011). Urokinase CDT achieved complete clot lysis in 80.7% of limbs (n = 21) compared with 84.2% of limbs (n = 16) treated with CDT plus PMT (P = .764). The incidences of major bleeding (CDT, 7.7%; CDT plus PMT, 5.3%; P = .749) and pulmonary embolism (CDT, 3.8%; CDT plus PMT, 5.3%; P = .818) were similar. The mean urokinase and PMT device cost for CDT alone was $10,127 compared with $5,128 for CDT plus PMT (P = .026). CONCLUSIONS: Percutaneous CDT with rheolytic PMT is as effective as CDT alone for acute iliofemoral DVT but requires significantly shorter treatment and lower lytic agent dose, resulting in lower costs. Randomized studies to confirm the benefits of pharmacomechanical thrombolysis in the treatment of DVT are warranted.     

Effect of aerobic training on orthostatic tolerance, circulatory response, and heart rate dynamics.

BACKGROUND: This study was performed to investigate the effects of aerobic training on orthostatic tolerance and to quantify the post-training changes in cardiovascular response and heart rate variability (HRV). METHODS: Tolerance and circulatory responses to two types of lower body negative pressure (LBNP) were examined and compared in a group of healthy male students before and after 6 mo of aerobic training, and the results were further compared with a group of athletes (runners). Changes in HRV associated with training were analyzed by conventional and time-varying autoregressive spectral analysis, as well as by approximate entropy measurement (ApEn)--a statistic quantifying heart rate "complexity" derived from non-linear dynamics. RESULTS: After aerobic training, there was an initial transient hypotension during the supine -50 mmHg LBNP testing and a significant decrease in tolerance to upright graded LBNP in most of the student-subjects. Moreover, after training, there was a significant decrease in ApEn value of the HRV time series during both supine control and LBNP testing, and the rate of cardiac vagal withdrawal and sympathetic activation during the onset of LBNP was faster than that before training. CONCLUSIONS: The present study has provided further evidence that certain types of aerobic training may affect orthostatic tolerance and may be associated with a loss of complexity of HRV during supine resting and orthostatic stress.     

Effectiveness of two versions of a sexually transmitted diseases/human immunodeficiency virus prevention program

Little is known about the comparative effectiveness of human immunodeficiency virus prevention interventions that differ in duration but contain similar content. The objective of this study was to evaluate and compare the effectiveness of two versions (6 hours vs. 3 hours) of a behavioral intervention called the STD/HIV Intervention Program (SHIP) in a sample of Marines. Marines were exposed to either a 6-hour or a 3-hour version of SHIP. Comparisons of pre-test and post-test knowledge, attitude, and behavioral intention scores revealed similar results for both versions. For both versions of the intervention, scores on sexually transmitted diseases/human immunodeficiency virus knowledge were significantly higher after the intervention. Both the 6-hour and the 3-hour versions of SHIP also led to significant increases on scales measuring social norms and behavioral intentions. The two versions of SHIP appeared to be of comparable effectiveness for producing short-term changes in knowledge, attitudes, and behavioral intentions.