Time filter

Source Type

Winnipeg, Canada

Elbakri I.A.,Cancercare Manitoba | Elbakri I.A.,University of Manitoba
Radiation Protection Dosimetry | Year: 2014

Dose-area product-to-effective dose (E) conversion factors for chest, abdomen and abdomen-chest neonatal radiographs were computed. Seven patient models in the Monte Carlo software, PCXMC, were defined, representing neonates ranging in weight from 0.5 to 6.0 kg. Conversion factors for a tube potential range of 50-80 kVp at two beam filtrations (3.0 mm Al and 3.0 mm Al10.1 mm Cu) were calculated. For 133 neonatal radiographs, effective dose values determined using these conversion factors were compared with those obtained from PCXMC simulations customised for each radiograph. For a 3.0-kg newborn irradiated at 60 kVp/3.0 mm Al beam filtration, the conversion factors were 2.58, 1.90 and 1.91 mSv (mGy cm2)21 for chest, chest-abdomen and abdomen radiographs, respectively. Average dose difference between the conversion factors and customised dose calculations was 16 %. Disagreement in effective dose was most strongly correlated with under-collimation in the lateral direction.

Flores-Tapia D.,Cancercare Manitoba
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2010

Currently, prostate cancer is the third leading cause of cancer-related deaths among men in North America. As with many others types of cancer, early detection and treatment greatly increases the patient's chance of survival. Combined Magnetic Resonance Imaging and Spectroscopic Imaging (MRI/MRSI) techniques have became a reliable tool for early stage prostate cancer detection. Nevertheless, their performance is strongly affected by the determination of the region of interest (ROI) prior to data acquisition process. The process of executing prostate MRI/MRSI techniques can be significantly enhanced by segmenting the whole prostate. A novel method for segmentation of the prostate in MRI datasets is presented. This method exploits the different behavior presented by signal singularities and noise in the wavelet domain in order to accurately detect the borders around the prostate. The prostate contour is then traced by using a set of spatially variant rules that are based on prior knowledge about the general shape of the prostate. The proposed method yielded promising results when applied to clinical datasets.

Kliewer E.V.,Cancercare Manitoba
Health reports / Statistics Canada, Canadian Centre for Health Information = Rapports sur la santé / Statistique Canada, Centre canadien d'information sur la santé | Year: 2010

BACKGROUND: With the recent introduction of a human papillomavirus (HPV) vaccine in Canada, it is important to establish surveillance and evaluation programs that not only track the uptake of the vaccine, but also assess its safety and its impact on: distribution of HPV type, cervical cancer screening programs, the incidence of anogenital warts, precancerous lesions and various cancers, and sexual behaviour. DATA SOURCES AND METHODS: Administrative databases, registries and questionnaire information are being linked to identify people receiving the HPV vaccine and to develop an evaluation system. INTERPRETATION: The availability of extensive linkable databases in Manitoba allows for the development of a comprehensive HPV vaccine surveillance and evaluation system that can address many of the questions related to the HPV vaccine. Aspects of the Manitoba surveillance and evaluation system could be implemented in other provinces that have similar databases.

Schultz A.S.H.,University of Manitoba | Nowatzki J.,Cancercare Manitoba | Ronson G.,University of Manitoba
American Journal of Public Health | Year: 2013

A Canadian biennial youth survey facilitated repeating investigation of susceptibility to smoke and household socialization. We operationalized susceptibility to smoke by 3 levels on the basis of intention and behavior. Variables consistently predicting greater susceptibility across time and age groups were sibling smoking, household restrictions, and vehicle smoke exposure. Gender was predictive among older youths. Household restrictions and emerging legislation to ban smoking in vehicles with youth passengers provide protection against secondhand smoke exposure and sustained resolve to remain smoke-free. Copyright © 2012 by the American Public Health Association®.

Flores-Tapia D.,Cancercare Manitoba | Flores-Tapia D.,University of Manitoba | Pistorius S.,University of Manitoba
Medical Physics | Year: 2011

Purpose: The purpose of this paper is to assess the experimental feasibility of a novel breast microwave radar reconstruction approach, circular holography, using realistic experimental datasets recorded using a preclinical experimental setup. The performance of this approach was quantitatively evaluated by calculating the signal to noise ratio, contrast to noise ratio, spatial accuracy, and reconstruction time. Methods: Six datasets were recorded, three corresponding to fatty cases and three containing synthetic dense tissue structures. Five of these datasets contained an 8 mm inclusion that emulated a malignant lesion. The data were acquired from synthetic phantoms that mimic the dielectric properties of breast tissues in the 1-6 GHz range using a custom experimental breast microwave radar system. The spatial accuracy and signal to noise ratio of the reconstructed was calculated for all the reconstructed images. The contrast to noise ratio of the reconstructed images corresponding to the datasets containing fibroglandular tissue regions was determined. This was done to evaluate the ability of the circular holographic method to provide images in which the responses from tumors can be distinguished from adjacent dense tissue structures. The execution time required to form the images was also measured to evaluate the data throughput of the holographic approach. Results: For all the reconstructed datasets, the location of the synthetic tumors in the experimental setup was consistent with its position in the reconstructed image. The average spatial error was 2.2 mm, which is less than half the spatial resolution of the data acquisition system. The average signal to noise ratio of the reconstructed images containing an artificial malignant lesion was 8.5 dB, while the average contrast to noise ratio was 6.7 dB. The reconstructed images presented no artifacts. The average execution time of the images formed using the proposed approach was 5 ms, which is six orders of magnitude faster than current state of the art breast microwave radar (BMR) reconstruction algorithms. Conclusions: The results show that circular holography is capable of forming accurate images with signal to noise levels higher than 8 dB in quasi real time. Compared to BMR reconstruction algorithms tested on datasets containing dense tissue structures, the holographic approach generated images of similar spatial accuracy with higher signal to noise ratios and an acceleration factor of one order of magnitude. © 2011 American Association of Physicists in Medicine.

Discover hidden collaborations