Perspective on Cancer Control: Whither the Tobacco Endgame for Canada?

Aims: In 2014, in response to evidence that Canada’s tobacco use would lead, inexorably, to substantial morbidity and mortality for the foreseeable future, a group of experts convened to consider the development of a “Tobacco Endgame” for Canada. The “Tobacco Endgame” defines a time frame in which to eliminate structural, political, and social dynamics that sustain tobacco use, leading to improved population health. Strategies: A series of Background Papers describing possible measures that could contribute to the creation of a comprehensive endgame strategy for Canada was prepared in advance of the National Tobacco Endgame Summit hosted at Queen’s University in 2016. At the summit, agreement was reached to work together to achieve <5% tobacco use by 2035 (<5 by ’35). A report of the proceedings was shared widely. Achievements: Progress since 2016 has been mixed. The Summit report was followed by a national forum convened by Health Canada in March 2017, and in 2018, the Canadian Government adopted “<5 × ’35” tobacco use target in a renewed Canadian tobacco reduction strategy. Tobacco use has declined in the last 5 years, but at a rate slower than that which will be needed to achieve the <5 by ’35 goal. There remain > 5 million smokers in Canada, signaling that smoking-related diseases will continue to be an enormous health burden. Furthermore, the landscape of new products (e-cigarettes and cannabis) has created additional risks and opportunities. Future directions: A bold, reinvigorated tobacco control strategy is needed that significantly advances ongoing policy developments, including full implementation of the key demand-reduction policies of the WHO Framework Convention on Tobacco Control. Formidable, new disruptive policies and regulations will be needed to achieve Canada’s Endgame goal.     

Analysis of localized quadratic encoding and reconstruction

Localized quadratic (LQ) encoding is a method of collecting multislice MRI data sets with greatly overlapping excited slices in such a way that the slice overlap can be deconvolved. This results in reconstructed data with resolution equal to the center-to-center slice spacing, regardless of the amount of excited slice overlap. LQ encoding is analyzed using the modulation transfer function of the encoding and reconstruction process. This allows analysis of many aspects of the technique in a well established theoretical framework. Many different characteristics of the method are explored, including excited slice profiles, required RF magnitudes and specific absorption rate, signal to noise ratio, signal dynamic range, reconstruction artifacts, sensitivity to motion, saturation and inflow effects, modulation transfer function shifting, and off-resonance artifacts. It is suggested that this technique is best suited for applications currently using multiple thin-slab three-dimensional encoding.     

Isolated brachial artery aneurysm: a rare presentation of paediatric Behçet’s disease

Behçet’s disease is a rare disease characterised by recurrent oral ulcers, with systemic manifestations including genital ulcers, ocular disease, skin lesions, gastrointestinal disease, neurologic disease, vascular disease and arthritis. Most clinical manifestations of Behçet’s disease are believed to be due to vasculitis. The heterogeneous clinical spectrum is influenced by sex, ethnicity and country of residence. Vascular manifestation in the form of isolated large brachial artery aneurysm is rare in children. Treatment involves aneurysmorrhaphy to avoid rupture or ischaemic sequelae in addition to lifelong medical management to control vasculitis.     

Accuracy assessment of three‐dimensional surface reconstructions of teeth from Cone Beam Computed Tomography scans

Summary The use of three‐dimensional (3D) models of the dentition obtained from cone beam computed tomography (CBCT) is becoming increasingly more popular in dentistry. A recent trend is to replace the traditional dental casts with digital CBCT models for diagnosis, treatment planning and simulation. The accuracy of these models was previously assessed through comparing linear physical and radiographical measurements. However, this assessment technique is both observer and landmark dependent. The accuracy of 3D CBCT teeth reconstructions is yet to be reliably measured. To assess the accuracy of 3D CBCT reconstructions of the teeth using a semi‐automated and observer‐independent method and to assess the influence of field of view (FoV) selection on reconstruction accuracy. Fully dentate upper and lower dry human jaws, placed in a plastic box and immersed in water, were scanned using CBCT with small, medium and large FoV. The teeth were then scanned separately using MicroCT. Cone beam computed tomography and MicroCT 3D teeth models were compared, and mean surface difference was calculated per tooth for each FoV. Mean and (maximum) differences between MicroCT and CBCT were 120 ± 40 (max. 679) μm, 157 ± 39 (max. 824) μ and 207 ± 80 (max. 862) μm for the small, medium and large FoV, respectively. Cone beam computed tomography models were larger than MicroCT because of larger voxel size. Our results indicate that CBCT may provide accurate 3D reconstructions of the teeth that can be useful for some clinical applications.