Sunnybrook Health Sciences Centre

About: Sunnybrook Health Sciences Centre is a healthcare organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Population & Medicine. The organization has 7689 authors who have published 15236 publications receiving 523019 citations. The organization is also known as: Sunnybrook.

Elastic moduli of normal and pathological human breast tissues: an inversion-technique-based investigation of 169 samples

Abstract: Understanding and quantifying the mechanical properties of breast tissues has been a subject of interest for the past two decades. This has been motivated in part by interest in modelling soft tissue response for surgery planning and virtual-reality-based surgical training. Interpreting elastography images for diagnostic purposes also requires a sound understanding of normal and pathological tissue mechanical properties. Reliable data on tissue elastic properties are very limited and those which are available tend to be inconsistent, in part as a result of measurement methodology. We have developed specialized techniques to measure tissue elasticity of breast normal tissues and tumour specimens and applied them to 169 fresh ex vivo breast tissue samples including fat and fibroglandular tissue as well as a range of benign and malignant breast tumour types. Results show that, under small deformation conditions, the elastic modulus of normal breast fat and fibroglandular tissues are similar while fibroadenomas were approximately twice the stiffness. Fibrocystic disease and malignant tumours exhibited a 3-6-fold increased stiffness with high-grade invasive ductal carcinoma exhibiting up to a 13-fold increase in stiffness compared to fibrogalndular tissue. A statistical analysis showed that differences between the elastic modulus of the majority of those tissues were statistically significant. Implications for the specificity advantages of elastography are reviewed.

Antiangiogenic therapy: impact on invasion, disease progression, and metastasis

Abstract: Antiangiogenic drugs targeting the VEGF pathway have slowed metastatic disease progression in some patients, leading to progression-free survival (PFS) and overall survival benefits compared with controls. However, the results are more modest than predicted by most preclinical testing and benefits in PFS are frequently not accompanied by overall survival improvements. Questions have emerged about the basis of drug resistance and the limitations of predictive preclinical models, and also about whether the nature of disease progression following antiangiogenic therapy is different to classic cytotoxic therapies-in particular whether therapy may lead to more invasive or metastatic behavior. In addition, because of recent clinical trial failures of antiangiogenic therapy in patients with early-stage disease, and the fact that there are hundreds of trials underway in perioperative neoadjuvant and adjuvant settings, there is now greater awareness about the lack of appropriate preclinical testing that preceded these studies. Improved preclinical assessment of all stages of metastatic disease should be a priority for future antiangiogenic drug discovery and development.

X-ray detectors for digital radiography

Abstract: Digital radiography offers the potential of improved image quality as well as providing opportunities for advances in medical image management, computer-aided diagnosis and teleradiology. Image quality is intimately linked to the precise and accurate acquisition of information from the x-ray beam transmitted by the patient, i.e. to the performance of the x-ray detector. Detectors for digital radiography must meet the needs of the specific radiological procedure where they will be used. Key parameters are spatial resolution, uniformity of response, contrast sensitivity, dynamic range, acquisition speed and frame rate. The underlying physical considerations defining the performance of x-ray detectors for radiography will be reviewed. Some of the more promising existing and experimental detector technologies which may be suitable for digital radiography will be considered. Devices that can be employed in full-area detectors and also those more appropriate for scanning x-ray systems will be discussed. These include various approaches based on phosphor x-ray converters, where light quanta are produced as an intermediate stage, as well as direct x-ray-to-charge conversion materials such as zinc cadmium telluride, amorphous selenium and crystalline silicon.

The Treatment of Unrelated Disorders in Patients with Chronic Medical Diseases

Abstract: Background Patients can have several illnesses concurrently, yet some of these diseases may be neglected if one problem consumes attention. We conducted a population-based analysis in Ontario, Canada — where universal health insurance is provided — to determine whether unrelated disorders are less likely to be treated in patients with chronic diseases. Methods We studied the 1,344,145 residents of Ontario in 1995 who were 65 or older and eligible to receive prescription medications free of charge as part of the Ontario Drug Benefit program. Patients with diabetes mellitus were identified by prescriptions for insulin, pulmonary emphysema by prescriptions for ipratropium bromide, and psychotic syndromes by prescriptions for haloperidol. For each chronic disease, we selected an unrelated treatment: estrogen-replacement therapy for patients with diabetes mellitus, lipid-lowering medications for those with pulmonary emphysema, and medical treatment of arthritis for those with psychotic syndromes. Results The 3...