TY - JOUR T1 - Patient Dosimetry of Intravenously Administered <sup>99m</sup>Tc-Annexin V JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 382 LP - 387 VL - 42 IS - 2 AU - Gerrit J. Kemerink AU - Ing Han Liem AU - Leo Hofstra AU - Hendrikus H. Boersma AU - Wil C.A.M. Buijs AU - Chris P.M. Reutelingsperger AU - Guido A.K. Heidendal Y1 - 2001/02/01 UR - http://jnm.snmjournals.org/content/42/2/382.abstract N2 - Annexin V labeled with 99mTc is evaluated as a potential in vivo marker for tissue with increased apoptosis. Promising results in patients have been obtained with 99mTc-(n-1-imino-4-mercaptobutyl)-annexin V (99mTc-i-AnxV). Because information on biodistribution and radiation burden is desired for the application of any radiopharmaceutical, a dosimetric study of 99mTc-i-AnxV was undertaken. Methods: Eight persons with normal kidney and liver functions were included in this study: six patients with myocardial infarction, one with Crohn’s disease, and one healthy volunteer. Approximately 600 MBq 99mTc-i-AnxV were injected intravenously immediately before a dynamic study with a dual-head gamma camera in conjugate view mode. In the next 24 h, two to four whole-body scans were acquired. Patient thickness was determined from a transmission scan with a 57Co flood source. Organ uptake was estimated after correction for background, attenuation, and scatter, using a depth-independent buildup factor and an organ-size–dependent attenuation correction. Residence times were calculated from the dynamic and whole-body studies and used as input for the MIRDOSE 3.1 program to obtain organ-absorbed doses and effective dose. Results: Activity strongly accumulated in the kidneys (21% ± 6% of the injected dose at 4 h postinjection) and the liver (12.8% ± 2.2%). Uptake in the target tissues (myocardium or colon) was limited and negligible from a dosimetric point of view. The biologic half-life of activity registered over the total body was 62 ± 13 h. Of the excreted activity, ∼75% went to the urine and 25% to the feces. The absorbed dose for the more strongly exposed organs was (in μGy/MBq): kidneys, 93 ± 24; spleen, 22 ± 6; liver, 17 ± 2; testes, 15 ± 3; thyroid, 10 ± 6; urinary bladder wall, 7.5 ± 2.6; and red bone marrow, 5.5 ± 0.8. The effective dose was 9.7 ± 1.0 μSv/MBq, corresponding to a total effective dose of 5.8 ± 0.6 mSv for a nominally injected activity of 600 MBq. Conclusion: 99mTc-i-AnxV strongly accumulates in the kidneys and to a lesser degree in the liver. The associated effective dose per MBq is in the midrange of values found for routine 99mTc-labeled compounds. From a dosimetric point of view 99mTc-i-AnxV is therefore well suited for the study of apoptosis in patients. ER -