Aims Conventional methodology using destructive sampling, which is laborious and has poor spatial and temporal resolution, has limited our understanding of soil-plant interactions. New non-invasive tomographic techniques have the potential to significantly improve our knowledge. In this study we demonstrated the simultaneous use of PET (positron emission tomography) and CT (X-ray computed tomography) to (a) non-destructively image a whole plant growing in sand, and (b) to link the observed morphology with recently assimilated C. The PET scanner was used to detect and visualize the location of the short-lived radioisotope 11 C (with a half-life of 20.4 min) taken up by the plant through 11 C-labelled CO 2 . This provided information on carbon translocation and the metabolism of photo-assimilates in the plant as well as root structure. The CT scanners yielded data on soil and root structure. Methods A medical PET/CT scanner was used to scan a fodder radish plant growing in a pot with test soil composed of homogenous sand. We constructed an air-plant-soil controller system (APS) to control the environmental conditions, such as CO 2 , temperature and light during the experiment. The plant was allowed to assimilate 11 CO 2 for 90 min before PET scanning was initiated. We carried out PET scanning for 60 min. Subsequently, the aerial parts of the plant was cut off and the pot was rescanned using a micro-CT scanner to obtain more detailed information on structure of the root system and the growth medium structure. Results The acquired PET and CT images gave images clearly visualizing the architecture and morphology of root and soil. Using a CT scanner, we were able to detect the main taproot located at 0 to 30 mm depth. With the PET scanner, we were able to measure a signal down to 82 mm below the surface of the sand. We found the highest concentration of 11 C at the position of the main root. The PET images, at different time intervals, showed the translocation and metabolisation of photo-assimilates from top to root. Using the micro-CT scanner (voxel size of 90 μm), we were able to detect roots down to 100 mm depth. These findings correlated the PET signals measured down to 82 mm depth.

Purpose: Copper is essential for enzymatic processes throughout the body. [ 64 Cu]copper (64 Cu) positron emission tomography (PET) has been investigated as a diagnostic tool for certain malignancies, but has not yet been used to study copper homeostasis in humans. In this study, we determined the hepatic removal kinetics, biodistribution and radiation dosimetry of 64 Cu in healthy humans by both intravenous and oral administration. Methods: Six healthy participants underwent PET/CT studies with intravenous or oral administration of 64 Cu. A 90 min dynamic PET/CT scan of the liver was followed by three whole-body PET/CT scans at 1.5, 6, and 20 h after tracer administration. PET data were used for estimation of hepatic kinetics, biodistribution, effective doses, and absorbed doses for critical organs. Results: After intravenous administration, 64 Cu uptake was highest in the liver, intestinal walls and pancreas; the gender-averaged effective dose was 62 ± 5 μSv/ MBq (mean ± SD). After oral administration, 64 Cu was almost exclusively taken up by the liver while leaving a significant amount of radiotracer in the gastrointestinal lumen, resulting in an effective dose of 113 ± 1 μSv/MBq. Excretion of 64 Cu in urine and faeces after intravenous administration was negligible. Hepatic removal kinetics showed that the clearance of 64 Cu from blood was 0.10 ± 0.02 mL blood/min/mL liver tissue, and the rate constant for excretion into bile or blood was 0.003 ± 0.002 min − 1. Conclusion: 64 Cu biodistribution and radiation dosimetry are influenced by the manner of tracer administration with high uptake by the liver, intestinal walls, and pancreas after intravenous administration, while after oral administration, 64 Cu is rapidly absorbed from the gastrointestinal tract and deposited primarily in the liver. Administration of 50 MBq 64 Cu yielded images of high quality for both administration forms with radiation doses of approximately 3.1 and 5.7 mSv, respectively, allowing for sequential studies in humans.

The article deals with the structure and presumed functions of the escal photophore found in the bulbous tip of the cephalic fin ray or illicium, situated on the upper part of the head in metamorphosed females in most species of deep‐sea anglerfishes (ceratioids). The escal photophore consists of the light gland proper and certain accessory structures. An accessory structure common to all species is a lightproof cup enclosing the light gland and provided with a distal opening, while the escae in a number of ceratioids in addition posses reflecting structures, tubular modifications of which form light guides in some species. The light gland proper is a roughly oval or spherical body, typically consisting of radiating branched glandular tubules arranged around a central escal cavity which communicates with the exterior via the vestibule, a usually slit‐like epithelium‐lined space lying above the distal part of the light gland. All lumina within the light gland contain bioluminescent symbiotic bacteria. The esca is generally thought to function as a lure, prey being attracted by the light emitted from the photophore and movements of the illicium. A possible additional function may be the ejection of a luminous material to confuse predators.

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Background and Aims Wilson’s disease (WD) is a genetic disease with systemic accumulation of copper that leads to symptoms from the liver and brain. However, the underlying defects in copper transport kinetics are only partly understood. We sought to quantify hepatic copper turnover in patients with WD compared with heterozygote and control subjects using PET with copper‐64 (64Cu) as a tracer. Furthermore, we assessed the diagnostic potential of the method. Approach and Results Nine patients with WD, 5 healthy heterozygote subjects, and 8 healthy controls were injected with an i.v. bolus of 64Cu followed by a 90‐min dynamic PET scan of the liver and static whole‐body PET/CT scans after 1.5, 6, and 20 h. Blood 64Cu concentrations were measured in parallel. Hepatic copper retention and redistribution were evaluated by standardized uptake values (SUVs). At 90 min, hepatic SUVs were similar in the three groups. In contrast, at 20 h postinjection, the SUV in WD patients (mean ± SEM, 31 ± 4) was higher than in heterozygotes (24 ± 3) and controls (21 ± 4; p < 0.001). An SUV‐ratio of hepatic 64Cu concentration at 20 and 1.5 h completely discriminated between WD patients and control groups (p < 0.0001; ANOVA). By Patlak analysis of the initial 90 min of the PET scan, the steady‐state hepatic clearance of 64Cu was estimated to be slightly lower in patients with WD than in controls (p = 0.04). Conclusions 64Cu PET imaging enables visualization and quantification of the hepatic copper retention characteristic for WD patients. This method represents a valuable tool for future studies of WD pathophysiology, and may assist the development of therapies, and accurate diagnosis.