CHOLINE C-11
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CHOLINE C-11 (CHOLINE C-11).
Choline C-11 is a radioactive diagnostic agent; after intravenous administration, it is taken up by cells and phosphorylated by choline kinase. It accumulates in tissues with high choline metabolism, such as tumors (e.g., prostate cancer), allowing positron emission tomography (PET) imaging. The mechanism for tumor uptake is related to increased cell membrane synthesis and choline kinase activity.
| Metabolism | Choline C-11 is rapidly metabolized in the body; it undergoes oxidation to betaine and further metabolism via the choline oxidation pathway. The primary enzymes involved are choline dehydrogenase and betaine aldehyde dehydrogenase. The radioactive carbon-11 decays by positron emission with a half-life of approximately 20.4 minutes. |
| Excretion | Primarily renal excretion; approximately 70-80% of administered radioactivity is eliminated in urine within 2 hours, with less than 5% fecal elimination. |
| Half-life | The terminal elimination half-life of [11C]choline in plasma is approximately 5-10 minutes. This short half-life is consistent with its use as a PET imaging agent, allowing same-day imaging without significant residual radiation exposure. |
| Protein binding | Approximately 5-10% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | The volume of distribution at steady state for [11C]choline is approximately 0.5 L/kg, indicating distribution primarily in total body water with some tissue binding. |
| Bioavailability | Intravenous administration: 100%. |
| Onset of Action | Not applicable (diagnostic agent). For PET imaging: uptake in target tissues begins immediately after intravenous injection, with peak tumor uptake typically occurring within 5-10 minutes. |
| Duration of Action | Not applicable (diagnostic agent). For PET imaging: optimal imaging window is between 5 and 20 minutes post-injection; radioactivity declines rapidly thereafter due to short physical half-life of carbon-11 (20.4 minutes). |
Intravenous: 370-740 MBq (10-20 mCi) as a single injection for PET imaging. Dose depends on patient weight, camera sensitivity, and imaging protocol.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment guidelines; renal excretion is minimal (<5% unchanged). Use standard dose unless severe impairment (eGFR <30 mL/min) may delay clearance; consider extended imaging. |
| Liver impairment | No specific dose adjustment; metabolism is hepatic but clearance is not significantly altered in mild-moderate impairment (Child-Pugh A/B). In severe (Child-Pugh C), use standard dose with caution due to potential altered distribution. |
| Pediatric use | Weight-based: 5.18 MBq/kg (0.14 mCi/kg) IV, minimum 37 MBq (1 mCi), maximum 370 MBq (10 mCi). Adjust per institutional protocols for pediatric PET imaging. |
| Geriatric use | No specific dose adjustment; use standard adult dose with consideration of age-related physiological changes (e.g., reduced renal function may minimally affect clearance). Monitor for injection site reactions. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CHOLINE C-11 (CHOLINE C-11).
| Breastfeeding | No human data on excretion in breast milk. M/P ratio unknown. Given radioactivity, discontinue breastfeeding for at least 12 hours after administration (half-life ~20 minutes). |
| Teratogenic Risk | Choline C-11 is a radioactive diagnostic agent. No human data on teratogenicity; animal reproduction studies not conducted. All trimesters: potential fetal harm from radiation exposure (risk depends on dose and gestational age). Use only if benefit justifies risk. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
Absolute: Hypersensitivity to choline or any component of the formulation. Relative: Pregnancy (risk of fetal radiation exposure), breastfeeding (discontinue nursing temporarily after administration).
| Precautions | Radiation exposure: The use of Choline C-11 increases the risk of radiation exposure, especially in patients with renal impairment. Allergic reactions: Hypersensitivity reactions, including anaphylaxis, have been reported. Imaging interpretation: False-positive and false-negative results may occur; clinical correlation is necessary. Drug interactions: None known. |
| Food/Dietary | No specific food interactions. Patients should avoid eating for 4-6 hours before the scan to reduce physiologic bowel uptake that may interfere with prostate imaging. |
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| Monitor maternal vital signs during injection. No specific fetal monitoring required; minimize radiation exposure to conceptus. |
| Fertility Effects | No data on fertility effects in humans. Radiation exposure may theoretically affect gonadal function; consider risk-benefit. |
| Clinical Pearls | Choline C-11 is a PET imaging agent used primarily for prostate cancer recurrence detection. Uptake is increased in malignant cells due to upregulated choline kinase. False positives can occur in benign prostatic hyperplasia and inflammation. Scan interpretation requires correlation with PSA levels and prior imaging. Optimal imaging time is 5-10 minutes post-injection due to rapid tracer clearance. |
| Patient Advice | This is a diagnostic imaging agent, not a treatment. · You will receive an intravenous injection of a small amount of radioactive material. · The scan takes about 30-60 minutes; remain still during imaging. · Drink water before the scan to ensure adequate hydration for radiation clearance. · Inform your doctor if you are pregnant, breastfeeding, or have any prostate conditions besides cancer. |