A simple method for producing and purifying Sc-44 from a liquid target using low energy medical cyclotrons
Bibliographic record
Abstract
1096 Objectives Sc-44 is an attractive radioisotope to radiolabel various radiopharmaceuticals due to its 3.97 hr half-life and short positron range. We developed a simple method for the production of Sc-44 using a liquid target [1] on a 13 MeV medical cyclotron, in contrast to using a solid metal target. Methods A concentrated solution of Ca(NO3)2 (1.56 g/ml) was prepared and loaded into a standard water target followed by irradiation with 2 μA of 13 MeV protons for one hour. Sc-44g was produced via the Ca-44(p,n) reaction. After irradiation, the solution was withdrawn from the target, adjusted to pH 7 with 1 M NH4OH, and passed through a 0.22 μm Millex-GV filter [2]. Upon elution of Sc from the filter with 1.6 ml of 70-90°C 0.1 M HCl, the content of the eluent was assessed by gamma spectroscopy and subjected to proof of concept radiolabeling experiments with commercially available chelates. Results Sc-43, Sc-44g, Sc-44m and Sc-48 were identified after irradiation of non-enriched Ca (2.1% Ca-44), with the desired product Sc-44g being the prevalent species at end of bombardment. 101±4 μCi was purified from the irradiated target solution affording a mixture of Sc isotopes that were well separated from the bulk solution of unconverted Ca salts. Preliminary coordination experiments with well-established chelates suggest that the radiochemistry behaves as anticipated [3]. Conclusions We have utilized a liquid target system to produce research quantities of Sc-44g from non-enriched Ca on a small medical cyclotron. This approach is a viable route to obtain sufficient quantities for pre-clinical testing. A rapid filtration-based purification method and subsequent coordination was also demonstrated. Future studies with enriched Ca-44 are expected to improve production yields while reducing the amount of radioactive Sc impurities. By using enriched Ca-44 (95%) and increasing beam current to 5 μA, clinically useful quantities of Sc-44 (11 mCi) could be produced. Research Support The authors wish to thank the Canadian Institute for Health Research - Collaborative Health Research Project (CIHR-CHRP) for funding.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
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".