Quantitative imaging of bromine-76 and yttrium-86 with PET: a method for the removal of spurious activity introduced by cascade gamma rays

Positron Emission Tomography of bromine-76 and yttrium-86 results in the detection of coincident events that are not strictly associated with annihilation photon pairs. Instead, these coincidences occur because prompt gamma rays emitted by these nuclides result in cascades of photons that are emitted within the timing window of the PET scanner. Pairs of detected photons from these cascades are not angularly correlated and therefore contain little information regarding the location of their source. Furthermore, these coincidences are not removed by correction procedures (e.g., randoms, scatter) routinely applied to PET data. If left uncorrected, the cascade coincidences will result in spurious apparent activity within the PET images. A correction, applied within projection space, that removes the cascade coincidence signal from septa-in (i.e., two-dimensional) datasets is proposed and tested on phantom data.     

Cost-effectiveness,cost-utility,and cost-benefit studies in rheumatology: a review of the literature, 2001-2002

Economic analyses of prevention and treatment interventions in rheumatology are potentially powerful tools for evaluating many complex decisions facing clinical and public policy makers. Cost-effectiveness, cost-utility, and cost-benefit analyses allow for the assessment of the trade-offs between expended resources and expected health benefits. This review describes 12 cost-effectiveness analyses done in the past year. Each relates to a different intervention for a variety of rheumatologic conditions including osteoporosis, rheumatoid arthritis, the use of cyclooxygenase-II inhibitors, infected total joint replacements, back pain, and Lyme disease. While cost-effectiveness analyses of the use of the new biologic agents in rheumatoid arthritis have been presented at national meetings, these have yet to be published. Proper use of cost-effectiveness analysis could provide valuable evidence about treatment decisions for clinical and public policy makers in rheumatology.     

Reliability of peak cardiorespiratory responses in patients with moderate to severe traumatic brain injury

OBJECTIVE: To examine the test-retest reliability of acute physiologic responses in patients with traumatic brain injury (TBI). DESIGN: Repeated measures within 1 week. SETTING: Brain injury rehabilitation program and community rehabilitation hospital. PARTICIPANTS: Thirty-six inpatients or their legal guardians. INTERVENTIONS: Each patient performed a symptom-limited incremental cycle ergometer test to voluntary fatigue on 2 separate occasions within 1 week. MAIN OUTCOME MEASURES: Peak values of power output and cardiorespiratory responses measured with a metabolic cart interfaced with an electrocardiogram. RESULTS: Intraclass correlations between the 2 trials were as follows: power output,.96; absolute oxygen uptake,.98; relative oxygen uptake,.97; heart rate,.82; ventilation rate,.96; and respiratory exchange ratio,.81. Bland-Altman plots showed that all data points were within the 95% confidence limits of the mean value of the 2 trials for each variable. CONCLUSIONS: The reliability of the peak cardiorespiratory responses during non-weight-bearing exercise was high in patients with TBI in a controlled laboratory setting. Therefore, aerobic exercise programs can be accurately prescribed, and changes resulting from such interventions can be confidently evaluated in this population.     

Applications of sliding window reconstruction with cartesian sampling for dynamic contrast enhanced MRI

Applications of dynamic contrast enhanced MR imaging are increasing and require both high spatial resolution and high temporal resolution. Perfusion studies using susceptibility contrast in particular require very high temporal resolution. The sliding window reconstruction is a technique for increasing temporal resolution. It has previously been applied to radial and spiral sampling, but these schemes require extensive correction and interpolation during image reconstruction. Fourier raw data can be reconstructed simply and quickly using the fast fourier transform (FFT). This paper presents a new Fourier-based sampling scheme and sliding window reconstruction that facilitates fast scanning without needing correction or interpolation. This technique can be used on virtually any MR scanner since it requires no specialized hardware. It is implemented here as a dual gradient echo sequence providing simultaneous T(1)- and T(2)*-weighted images with a time resolution of 1.1 s.     

The dental curriculum in Gies' time,now, and in the future

Writing in the 1920s, William J. Gies was a champion for the importance of dentistry to general health, the scientific foundation for dentistry, and the need to develop and integrate an efficient curriculum. He argued that admissions standards should be made uniform and raised. He also proposed that the predoctoral dental curriculum should be reduced to three year's length by eliminating unnecessary material and improving efficiency. Gies called for available postgraduate experiences on an optional basis. Perhaps it is time to consider a three-plus-one model combining a three-year program focused on general dentistry with a mandatory fourth year along the lines of a postdoctoral general education experience.     

Effect of opioid and cannabinoid receptor antagonism on orphanin FQ-induced hyperphagia in rats

Feeding induced in rats by cerebroventricular (i.c.v.) injection of orphanin FQ was potently and dose-dependently reversed by peripheral injection of either the opioid antagonist naloxone or the cannabinoid CB(1) receptor antagonist SR 141716[N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophelyl)-4-methyl-3-pyrazole-carboxamine]. The combination of these two agents inhibited food intake in a manner suggestive of additivity or supra-additivity.     

Phase III clinical trial of the combination of cisplatin, dacarbazine, and carmustine with or without tamoxifen in patients with advanced malignant melanoma.

PURPOSE: A prospective randomized phase III clinical trial was conducted to assess whether the addition of tamoxifen (TAM) to the three-agent regimen of cisplatin (CDDP), dacarbazine (DTIC), and carmustine (BCNU) significantly increased the progression-free survival and overall survival of patients with advanced malignant melanoma. PATIENTS AND METHODS: Patients with advanced malignant melanoma were treated with CDDP + DTIC + BCNU (CDB) with or without TAM. The dose schedule was CDDP 25 mg/m(2) given intravenously (IV) for 30 to 45 minutes in 500 mL of dextrose and (1/2) normal saline (NS) on days 1 to 3 of a 3-week cycle; DTIC 220 mg/m(2) IV for 1 hour in 500 mL of dextrose and (1/2) NaCl on days 1 to 3 of a 3-week cycle; BCNU 150 mg/m(2) IV for 2 to 3 hours in 750 to 1,000 mL of dextrose and 5% water on day 1 of every odd 3-week cycle; and TAM 20 mg taken orally every morning. RESULTS: There were 184 eligible patients enrolled. These patients were observed until death or for a minimum of 1.3 years. At last contact, 12 were still alive. The median time to progression was 3.4 months on the CDB arm and 3.1 months on the CDB + TAM arm. The median survival time was 6.8 months with CDB and 6.9 months with CDB + TAM. Progression-free survival (P =.429) and overall survival (P =.545) were not found to differ by treatment. CONCLUSION: The addition of TAM to this three-agent regimen of CDB was not found to provide a meaningful clinical advantage in the treatment of patients with advanced malignant melanoma.