Accuracy of dynamic patient surface monitoring using a time-of-flight camera and B-spline modeling for respiratory motion characterization.

Time-of-flight (ToF) camera technology provides a real-time depth map of a scene with adequate frequency for the monitoring of physiological patient motion. However, dynamic surface motion estimation using a ToF camera is limited by issues such as the raw measurement accuracy and the absence of fixed anatomical landmarks. In this work we propose to overcome these limitations using surface modeling through B-splines. This approach was assessed in terms of both motion estimation accuracy and associated variability improvements using acquisitions of an anthropomorphic surface phantom for a range of observation distances (0.6-1.4 m). In addition, feasibility was demonstrated on patient acquisitions. Using the proposed B-spline modeling, the mean motion estimation error and associated repeatability with respect to the raw measurements decreased by a factor of 3. Significant correlation was found between patients' surfaces motion extracted using the proposed B-spline approach applied to the ToF data and the one extracted from synchronized 4D-CT acquisitions as the ground truth. ToF cameras represent a promising alternative for contact-less patient surface monitoring for respiratory motion synchronization or modeling in imaging and/or radiotherapy applications.

Restenosis following angioplasty in the swine coronary artery is inhibited by an orally active PDGF-receptor tyrosine kinase inhibitor, RPR101511A.

BACKGROUND: Platelet-derived growth factor (PDGF), a purported mediator of arterial response to injury, stimulates proliferation, chemotaxis, and matrix production by activation of its membrane receptor tyrosine kinase. Because these activities underlie restenosis, inhibition of the PDGF-receptor tyrosine kinase (PDGFr-TK) is postulated to decrease restenosis. METHODS AND RESULTS: RPR101511A is a novel compound which selectively and potently inhibits the cell-free and in situ PDGFr-TK and PDGFr-dependent proliferation and chemotaxis in vascular smooth muscle cells (VSMC). To evaluate the effect of RPR101511A (30 mg. kg-1. d-1 BID for 28 days following PTCA) on coronary restenosis, PTCA was performed in hypercholesterolemic minipigs whose left anterior descending (LAD) coronary artery had been injured by overdilation and denudation, yielding a previously existing lesion. Angiographically determined prePTCA minimal lumen diameters (MLD) were similar in vehicle and RPR101511A-treated pigs (1.98+/-0.09 versus 2.01+/-0.08 mm) and increased to the same extent in the 2 groups following successful PTCA (2.30+/-0.06 versus 2.52+/-0.13). At termination, there was an average 50% loss of gain in the vehicle-treated group but no loss of gain with RPR101511A (2.16+/-0. 05 versus 2.59+/-0.11, P<0.001). Morphometric analysis of the LAD showed that RPR101511A caused a significant decrease in total intimal/medial ratio (0.96+/-0.58 versus 0.67+/-0.09, P<0.05). CONCLUSIONS: RPR101511A, which acts by inhibition of the PDGFr-TK, completely prevented angiographic loss of gain following PTCA and significantly reduced histological intimal hyperplasia.

The FAS Screen: a rapid screening tool for fetal alcohol syndrome.

Fetal alcohol syndrome (FAS) is an important cause of mental retardation and developmental disabilities. A population based screening tool would allow for early diagnosis and entry into intervention programs. The aim of the study was to develop a brief screening tool for use in population-based settings to improve the identification of children with FAS. The FAS Screen was developed and tested in six sites. These were sites that served children and all were located in North Dakota. Screening was completed on 1013 children, 65 were found to have a positive screening score and were referred for further investigation. Forty were seen for evaluation by a medical geneticist and six were diagnosed with FAS. The estimated values for the screening tool were: specificity 94.1%, sensitivity 100%, positive predictive value 9.1% and negative predictive value 100%. The cost of screening was $13.00 per child and the cost per case identified was $4,100. The FAS Screen is a brief screening test with acceptable performance characteristics and is cost effective.

An investigation of the safety of the blood reinfusion step used with tunneled venous access devices in children with cancer.

Infection has been identified as the most serious potential complication of the indwelling catheter. As a result, the primary nursing goal using the catheters is to prevent infection. Nurses must frequently manipulate the catheters when securing blood specimens and are concerned that this manipulation may serve as a source of infection for the immunocompromised pediatric oncology patient. One particular step in catheter manipulation during blood sampling is blood reinfusion, ie, residual blood in the catheter is withdrawn and set aside while a second sample is collected for laboratory analysis but is subsequently returned to the patient through the catheter. The purpose of this study was to examine this nursing procedure for its potential of contaminating the blood sample that was to be reinfused, or for the potential of reinfusing a sample that contained preexisting pathogens independent of the procedure itself. An experimental design was used with 21 patients randomly assigned to an experimental group (unclean procedure to exaggerate the potential to incur pathogens during the process), and 21 randomly assigned to a control group (usual clean procedure followed with the reinfusion sample). The usual blood sampling procedure was altered for all participants as the typical amount of blood that normally constitutes the reinsertion sample was not reinserted, but was instead used to complete certain microbial analyses. Of the 42 participants, 17 were male and 25 were female; 35 were white and seven were black; 22 were diagnosed with leukemias and 20 with solid tumors. The age range for participants was 2 to 20 years (mean = 9.4 years, SD = 4.8).(ABSTRACT TRUNCATED AT 250 WORDS)