RESUMO
The radiation exposure of the hands of nuclear medicine laboratory technicians is largely due to the dispensing of radiopharmaceuticals into syringes. To reduce this exposure, a multiradionuclide automatic dispensing system (ADS) for syringes of radiopharmaceuticals was introduced. The aim of this study was to determine the effect of this ADS on hand dose compared with manual dispensing. Methods: The total hand dose per month for all personnel (12 technicians) was measured with ring dosimeters at the base of the index finger for 13 mo: 7 mo with manual syringe dispensing (radiopharmaceuticals containing 99mTc,18F, 177Lu, 68Ga, 90Y, and 223Ra) and 6 mo with ADS (automatic: radiopharmaceuticals containing 18F and 177Lu; manual: radiopharmaceuticals containing 99mTc, 68Ga, 90Y, and 223Ra). Results: The mean total hand dose per month was reduced from 52.8 ± 10.2 mSv with manual dispensing to 21.9 ± 2.7 mSv with ADS (P < 0.001), which is an absolute decrease of 59%. Meanwhile, the total handled activity increased from 369 to 505 GBq (P < 0.001). 18F-containing radiopharmaceuticals were the most commonly dispensed, at 182 GBq per month. The increase in total handled activity was largely due to an increase in 177Lu (from 25 to 123 GBq), partially because of the introduction of [177Lu]Lu-PSMA-I&T. When correcting for this increase in handled activity, the hand dose was reduced by 69%. Conclusion: The introduction of a multiradionuclide syringe ADS decreased the hand dose to personnel by 69% when corrected for the increase in handled activity. Expanding the number of radiopharmaceuticals being dispensed by the system could potentially further decrease personnel hand dose.
RESUMO
BACKGROUND: [177Lu]Lu-PSMA is used for the treatment of metastatic castration-resistant prostate cancer. For in-house productions, quality control methods are essential for ensuring product quality, and thus patient safety. During HPLC method development for quality control of [177Lu]Lu-PSMA-I&T, we noticed an unpredictable variability in peak area and height with replicate measurements. After a run, irremovable radioactivity was measured over the whole the length of the HPLC column, with slightly higher activity at the beginning and end of the column. The uniform distribution suggests that [177Lu]Lu-PSMA-I&T interacts with the column. As a result of the interaction, incomplete and variable recovery of injected activity was observed leading to the variability in peak area and height. Therefore the aim of this study was to (1) investigate the effect of sample composition on the interaction of [177Lu]Lu-PSMA-I&T to the HPLC column (measured as recovery, peak area, and peak height), and (2) to compare this with same concentrations of the well-known [177Lu]Lu-PSMA-617. RESULTS: Sample composition significantly affects recovery of [177Lu]Lu-PSMA-I&T, leading to a change in peak area and height. Recovery was 24% when diluted with 0.1 mM octreotide, 38% with water, and increased to 95% when diluted with 0.7 mM unlabeled PSMA-I&T. Peak area and height decreased to 26% and 17% when diluted in octreotide and to 41% and 29% when diluted in water, compared to a dilution in PSMA-I&T. Further experiments showed that recovery (and consequently peak area and peak height) reached a plateau of > 99% at concentrations of 0.27 mM and higher. [177Lu]Lu-PSMA-617 also interacts with the HPLC column, leading to lower, but less variable, recovery (9%). The low recovery of [177Lu]Lu-PSMA-617 could not be prevented with addition of unlabeled PSMA-617. CONCLUSION: [177Lu]Lu-PSMA-I&T can undergo an irreversible binding with an HPLC column resulting in a decreased recovery. The recovery is can be highly dependent on sample composition. The addition of a surplus of unlabeled PSMA-I&T leads to an accurate analysis of [177Lu]Lu-PSMA-I&T.
