Microfluidic beta and conversion electron radiation detector for preclinical pharmacokinetic studies with PET and SPECT radiotracers
Bibliographic record
Abstract
The characterization of new radiotracer pharmacokinetics in small animals is very challenging because of the small volume of blood available. For this purpose, a microfluidic blood counter prototype made of a microchannel on silicon containing PIN photodiodes was proposed to improve beta detection efficiency in a small volume by eliminating all unnecessary interfaces between blood and detector. In this work, a new optimized configuration with improved geometrical detection efficiency and new dedicated electronics have been investigated for the detection of positron-emitting radiotracers, and also for99mTc based radiotracers, detected via their low-energy (2cross section and 31.5 mm in length was microfabricated over a die containing an array of 2 × 2 mm2PIN photodiodes leaving only a 5-μm epoxy floor layer between the blood and the photodiode sensitive surface. CV-IV measurements were made at each fabrication steps to detect any detrimental effects of the microchannel on the diodes electrical characteristics. The microfluidic chip was wire bonded to a gold plated custom made PCB and connected to a custom-made signal processing board for pulse shaping and amplification. Absolute sensitivity was determined for the most popular PET and SPECT radioisotopes and ranged from 35 to 41% for PET tracers (18F,11C) and more than 4% for99mTc. Energy spectra recorded for different isotopes and calibrated with133Ba and241Am solid sources showed typical beta distribution spectra for PET isotopes and a characteristic peak corresponding to conversion electrons for99mTc. Input functions were successfully simulated with18F and99mTc, confirming that the setup is suitable for pharmacokinetic modeling of PET and SPECT radiotracers in animal experiments. The fabrication process uses standard materials and procedures and would allow the addition of microfluidic functionalities on-chip to enable full characterization of new radiotracers.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".