دورية أكاديمية
In-target production of [11C]CH4 from a nitrogen/hydrogen gas target as a function of beam current, irradiation time, and target temperature
| العنوان: | In-target production of [11C]CH4 from a nitrogen/hydrogen gas target as a function of beam current, irradiation time, and target temperature |
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| المؤلفون: | Semi Helin, Johan Rajander, Jussi Aromaa, Eveliina Arponen, Jatta S. Helin, Olof Solin |
| المصدر: | EJNMMI Radiopharmacy and Chemistry, Vol 9, Iss 1, Pp 1-19 (2024) |
| بيانات النشر: | SpringerOpen, 2024. |
| سنة النشر: | 2024 |
| المجموعة: | LCC:Medical physics. Medical radiology. Nuclear medicine LCC:Therapeutics. Pharmacology |
| مصطلحات موضوعية: | Carbon-11, [11C]methane, Targetry, PET, Haber–Bosch, Medical physics. Medical radiology. Nuclear medicine, R895-920, Therapeutics. Pharmacology, RM1-950 |
| الوصف: | Abstract Background Production of [11C]CH4 from gas targets is notorious for weak performance with respect to yield, especially when using high beam currents. Post-target conversion of [11C]CO2 to [11C]CH4 is a widely used roundabout method in 11C-radiochemistry, but the added complexity increase the challenge to control carrier carbon. Thus in-target-produced [11C]CH4 is superior with respect to molar activity. We studied the in-target production of [11C]CO2 and [11C]CH4 from nitrogen gas targets as a function of beam current, irradiation time, and target temperature. Results [11C]CO2 production was practically unchanged across the range of varied parameters, but the [11C]CH4 yield, presented in terms of saturation yield YSAT(11CH4), had a negative correlation with beam current and a positive correlation with target chamber temperature. A formulated model equation indicates behavior where the [11C]CH4 formation follows a parabolic graph as a function of beam current. The negative square term, i.e., the yield loss, is postulated to arise from Haber–Bosch-like NH3 formation: N2 + 3H2 → 2NH3. The studied conditions suggest that the NH3 (liq.) would be condensed on the target chamber walls, thus depleting the hydrogen reserve needed for the conversion of nascent 11C to [11C]CH4. Conclusions [11C]CH4 production can be improved by increasing the target chamber temperature, which is presented in a mathematical formula. Our observations have implications for targetry design (geometry, gas volume and composition, pressure) and irradiation conditions, providing specific knowledge to enhance [11C]CH4 production at high beam currents. Increased [11C]CH4 radioactivity is an obvious benefit in radiosynthesis in terms of product yield and molar radioactivity. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 2365-421X |
| Relation: | https://doaj.org/toc/2365-421X |
| DOI: | 10.1186/s41181-024-00255-1 |
| URL الوصول: | https://doaj.org/article/c3a3170e088d48a3ad8469f5dd8d312d |
| رقم الأكسشن: | edsdoj.3a3170e088d48a3ad8469f5dd8d312d |
| قاعدة البيانات: | Directory of Open Access Journals |
Find this article in full text from Springer Verlag. 
Full Text Finder | تدمد: | 2365421X |
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| DOI: | 10.1186/s41181-024-00255-1 |