If you build it, will they come? Is test site availability a root cause of geographic disparities in COVID-19 testing?

OBJECTIVES: The purpose of this study was to examine the relationship between test site availability and testing rate within the context of social determinants of health. STUDY DESIGN: A retrospective ecological investigation was conducted using statewide COVID-19 testing data between March 2020 and December 2021. METHODS: Ordinary least squares and geographically weighted regression were used to estimate state and ZIP code level associations between testing rate and testing sites per capita, adjusting for neighbourhood-level confounders. RESULTS: The findings indicate that site availability is positively associated with the ZIP code level testing rate and that this association is amplified in communities of greater economic deprivation. In addition, economic deprivation is a key factor for consideration when examining ethnic differences in testing in medically underserved states. CONCLUSION: The study findings could be used to guide the delivery of testing facilities in resource-constrained states.

Design and initial performance of PlanTIS: a high-resolution positron emission tomograph for plants.

Positron emitters such as (11)C, (13)N and (18)F and their labelled compounds are widely used in clinical diagnosis and animal studies, but can also be used to study metabolic and physiological functions in plants dynamically and in vivo. A very particular tracer molecule is (11)CO(2) since it can be applied to a leaf as a gas. We have developed a Plant Tomographic Imaging System (PlanTIS), a high-resolution PET scanner for plant studies. Detectors, front-end electronics and data acquisition architecture of the scanner are based on the ClearPET system. The detectors consist of LSO and LuYAP crystals in phoswich configuration which are coupled to position-sensitive photomultiplier tubes. Signals are continuously sampled by free running ADCs, and data are stored in a list mode format. The detectors are arranged in a horizontal plane to allow the plants to be measured in the natural upright position. Two groups of four detector modules stand face-to-face and rotate around the field-of-view. This special system geometry requires dedicated image reconstruction and normalization procedures. We present the initial performance of the detector system and first phantom and plant measurements.