This imaging study measured how well handheld surgical probes detect gamma signal from the radioactive isotope indium-111 and fluorescence from a near-infrared dye through layers of pig tissue and gelatin. Gamma signal from indium-111 was detected through much thicker tissue than fluorescence. The work concerns a medical radiotracer and has no bearing on dietary indium.
Key numbers
- At least 5% of maximum gamma signal from indium-111 was detected through up to 5 cm of tissue or gelatin, versus up to 0.5 cm for fluorescence, depending on overlying tissue (Abstract).
- Tracer-bearing tumors: gamma signal detected through at least 5 cm of air, 4.3 ± 0.29 cm of liver, 3.0 ± 0.5 cm of fat, 3.2 ± 0.29 cm of muscle and 3.5 cm of lung (Results, p. S13705-5).
- This paper reports no numerical findings relevant to indium exposure.
Methods (brief)
Neuroblastoma xenografts in nude mice were labeled with an indium-111 and IRDye800CW dual tracer, resected, and placed under porcine tissue or gelatin in 3D-printed molds; a gamma probe and a fluorescence camera measured signal versus thickness.
Evidence fitness
Off-topic for dietary exposure. It concerns the detection of a medical radioisotope through tissue and does not support dietary exposure, food occurrence or toxicity claims for indium.
Limitations
Phantom and animal tissue model; radioactive dose to patients is not addressed. Several authors report a patent application on a dual-labeled tracer.
Related evidence
Update history
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