METHODS: In this study, prior to synthesis, quality control analysis method for 18F-Fluorocholine was developed and validated, by adapting the equipment set-up used in 18F-Fluorodeoxyglucose (18FFDG) routine production. Quality control on the 18F-Fluorocholine was performed by means of pH, radionuclidic identity, radio-high performance liquid chromatography equipped with ultraviolet, radio- thin layer chromatography, gas chromatography and filter integrity test.
RESULTS: Post-synthesis; the pH of 18F-Fluorocholine was 6.42 ± 0.04, with half-life of 109.5 minutes (n = 12). The radiochemical purity was consistently higher than 99%, both in radio-high performance liquid chromatography equipped with ultraviolet (r-HPLC; SCX column, 0.25 M NaH2PO4: acetonitrile) and radio-thin layer chromatography method (r-TLC). The calculated relative retention time (RRT) in r-HPLC was 1.02, whereas the retention factor (Rf) in r-TLC was 0.64. Potential impurities from 18F-Fluorocholine synthesis such as ethanol, acetonitrile, dimethylethanolamine and dibromomethane were determined in gas chromatography. Using our parameters, (capillary column: DB-200, 30 m x 0.53 mm x 1 um) and oven temperature of 35°C (isothermal), all compounds were well resolved and eluted within 3 minutes. Level of ethanol and acetonitrile in 18F-Fluorocholine were detected below threshold limit; less than 5 mg/ml and 0.41 mg/ml respectively. Meanwhile, dimethylethanolamine and dibromomethane were undetectable.
CONCLUSION: A convenient, efficient and reliable quality control analysis work-up procedure for 18FFluorocholine has been established and validated to comply all the release criteria. The convenient method of quality control analysis may provide a guideline to local GMP radiopharmaceutical laboratories to start producing 18F-Fluorocholine as a tracer for prostate cancer imaging.
AIM: This study seeks to evaluate the effective radiation doses associated with common diagnostic and treatment procedures, as well as propose diagnostic reference levels (DRLs), within two nuclear medicine centers in Madinah, Saudi Arabia.
METHODOLOGY: Data from 445 patients were gathered from two nuclear medicine centers in the Madinah region of Saudi Arabia. The data were categorized based on the type of nuclear medicine (NM) procedure, the chemical composition of the administered radiopharmaceutical, as well as patient age and weight. Effective radiation doses for prevalent NM procedures were computed, and suggested DRLs were formulated.
RESULTS: Effective radiation doses were analyzed for 16 adult and 2 pediatric NM procedures (divided into 8 groups). The effective radiation doses for adult diagnostic nuclear medicine procedures range from 0.05 mSv (Nanocoloid) to 29 mSv (67Ga-citrate). For pediatric procedures, the doses range from 0.80 mSv (5-year-old undergoing renal DTPA) to 1.6 mSv (1-year-old undergoing renal DMSA). Furthermore, DRL values were determined for both adult and pediatric NM procedures. The study's findings demonstrated a high degree of concordance between effective radiation doses and DRL values, aligning well with previously published research.
CONCLUSION: While the effective radiation doses outlined in this study were generally within acceptable limits and consistent with prior research findings, optimizing radiation doses remains imperative, particularly for pediatric NM procedures.
OBJECTIVE: In this presented work, an analytical method by gas chromatography coupled with flame ionization detection (GC-FID) has been developed to determine organic solvents in radiopharmaceutical samples. The effect of injection holding time, temperature variation in the injection port, and the column temperature on the analysis time and resolution (R ≥ 1.5) of ethanol and acetonitrile was studied extensively.
METHODS: The experimental conditions were optimized with the aid of further statistical analysis; thence, the proposed method was validated following the International Council for Harmonisation (ICH) Q2 (R1) guideline.
RESULTS: The proposed analytical method surpassed the acceptance criteria including the linearity > 0.990 (correlation coefficient of R2), precision < 2%, LOD, and LOQ, accuracy > 90% for all solvents. The separation between ethanol and acetonitrile was acceptable with a resolution R > 1.5. Further statistical analysis of Oneway ANOVA revealed that the increment in injection holding time and variation of temperature at the injection port did not significantly affect the analysis time. Nevertheless, the variation in injection port temperature substantially influenced the resolution of ethanol and acetonitrile peaks (p < 0.05).
CONCLUSION: The proposed analytical method has been successfully implemented to determine the organic solvent in the [18F]fluoro-ethyl-tyrosine ([18F]FET), [18F]fluoromisonidazole ([18F]FMISO), and [18F]fluorothymidine ([18F]FLT).
OBJECTIVE: To evaluate the initial staging discrepancy between conventional contrasted computed tomography (CT) and 18F-fluorodeoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) and its impact on management plans for head and neck malignancies.
DESIGN AND SETTING: Prospective cross-sectional study in two tertiary-level hospitals.
METHODS: This study included 30 patients with primary head and neck malignant tumors who underwent contrasted computed tomography and whole-body 18F-FDG PET/CT assessments. The staging and treatment plans were compared with the incremental information obtained after 18F-FDG PET/CT.
RESULTS: 18F-FDG PET/CT was found to raise the stage in 33.3% of the cases and the treatment intent was altered in 43.3% of them, while there was no management change in the remaining 56.7%. 18F-FDG PET/CT had higher sensitivity (96% versus 89.2%) and accuracy (93% versus 86.7%) than conventional contrast-enhanced computed tomography.
CONCLUSION: Our study demonstrated that 18F-FDG PET/CT had higher sensitivity and accuracy for detecting head and neck malignancy, in comparison with conventional contrast-enhanced computed tomography. 18F-FDG PET/CT improved the initial staging and substantially impacted the management strategy for head and neck malignancies.