Photon-counting detectors are promising candidates for use in the next generation of x-ray computed tomography (CT) scanners. Among the foreseen benefits are higher spatial resolution, better trade-off between noise and dose and energy discriminating capabilities. Silicon is an attractive detector material because of its low cost, mature manufacturing process and high hole mobility. However, it is sometimes overlooked for CT applications because of its low absorption efficiency and high fraction of Compton scatter. The purpose of this work is to demonstrate that silicon is a feasible material for CT detectors by showing energy-resolved CT images acquired with an 80 kVp x-ray tube spectrum using a photon-counting silicon-strip detector with eight energy thresholds developed in our group. We use a single detector module, consisting of a linear array of 50 0.5×0.4 mm detector elements, to image a phantom in a table-top lab setup. The phantom consists of a plastic cylinder with circular inserts containing water, fat and aqueous solutions of calcium, iodine and gadolinium, in different concentrations. By using basis material decomposition we obtain water, calcium, iodine and gadolinium basis images and demonstrate that these basis images can be used to separate the different materials in the inserts. We also show results showing that the detector has potential for quantitative measurements of substance concentrations.

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Background: The aim of this study was to compare the risks of new-onset prostate cancer between metformin and sulfonylurea users with type 2 diabetes mellitus (T2DM). Methods: This population-based retrospective cohort study included male patients with T2DM presenting to public hospitals/clinics in Hong Kong between January 1, 2000, and December 31, 2009. We only included patients prescribed either, but not both, metformin or sulfonylurea. All patients were followed up until December 31, 2019. The primary outcome was new-onset prostate cancer and the secondary outcome was all-cause mortality. One-to-one propensity score matching was performed between metformin and sulfonylurea users based on demographics, comorbidities, antidiabetic and cardiovascular medications, fasting blood glucose level, and hemoglobin A1c level. Subgroup analyses based on age and use of androgen deprivation therapy were performed. Results: The final study cohort consisted of 25,695 metformin users (mean [SD] age, 65.2 [11.8] years) and 25,695 matched sulfonylurea users (mean [SD] age, 65.3 [11.8] years) with a median follow-up duration of 119.6 months (interquartile range, 91.7–139.6 months) after 1:1 propensity score matching of 66,411 patients. Metformin users had lower risks of new-onset prostate cancer (hazard ratio, 0.80; 95% CI, 0.69–0.93; P=.0031) and all-cause mortality (hazard ratio, 0.89; 95% CI, 0.86–0.92; P<.0001) than sulfonylurea users. Metformin use was more protective against prostate cancer but less protective against all-cause mortality in patients aged <65 years (P for trend <.0001 for both) compared with patients aged ≥65 years. Metformin users had lower risk of all-cause mortality than sulfonylurea users, regardless of the use of androgen deprivation therapy (P for trend <.0001) among patients who developed prostate cancer. Conclusions: Metformin use was associated with significantly lower risks of new-onset prostate cancer and all-cause mortality than sulfonylurea use in male patients with T2DM.

Background The effects of sodium-glucose cotransporter 2 inhibitors (SGLT2I) vs dipeptidyl peptidase-4 inhibitors (DPP4I) on the risk of new-onset gout remains unknown. This study aims to compare the effects of SGLT2I against DPP4I on gout risks. Methods This was a retrospective population-based cohort study of patients with type-2 diabetes mellitus treated with SGLT2I or DPP4I between January 1st, 2015 and December 31st, 2020 in Hong Kong. The study outcomes are new-onset gout and all-cause mortality. Propensity score matching (1:1 ratio) between SGLT2I and DPP4I was performed. Univariable and multivariable Cox regression analysis models were conducted. Competing risks models and multiple approaches based on the propensity score were applied. Results This study included 43201 patients (median age: 63.23 years old [Interquantile range, IQR]: 55.21–71.95, 53.74% males; SGLTI group: n = 16144; DPP4I group: n = 27057) with a median follow-up of 5.59 years (IQR: 5.27–5.81 years) since initial drug exposure. The incidence rate of developing gout (Incidence rate [IR]: 2.5; 95% CI: 2.2–2.9) among SGLT2I users was significantly lower than DPP4I users (IR: 5.2; 95% CI: 4.8–5.8). SGLT2 was associated with 51% lower risks of gout (HR: 0.49; 95% CI: 0.42–0.58; P-value &lt; 0.0001) and 51% lower risks of all-cause mortality (HR: 0.49; 95% CI: 0.42–0.58; P-value &lt; 0.0001) after adjusting for significant demographics, past comorbidities, medications, and laboratory results. The results remained consistent on competing risk and other propensity score approaches. Conclusions SGLT2I use was associated with lower risks of new gout diagnosis compared with DPP4I use.