ABSTRACT
INTRODUCTION: The aim of our work is to quantify the radiation damage in lymphocytes after labelling with [18F]FDG. Comparison with gold standard [99mTc]HMPAO labelling is established. An approach to cellular dosimetry is proposed. METHODS: Mixed leukocytes were separated from fresh venous blood and labelled with [18F]FDG and [99mTc]HMPAO following published guidelines. Cytokinesis-block micronucleus (CBMN) assay was performed for both sets of experiments. Tests for quality control of labelling described in guidelines were followed. Cellular dosimetry was calculated according to MIRD. RESULTS: MN scored after labelling with 37 MBq of [18F]FDG were 956 ± 172 and 347 ± 26 for [99mTc]HMPAO (p < 0.05). Absorbed dose in cell nucleus was of 0.23 Gy for [18F]FDG and 0.08 Gy for [99mTc]HMPAO labelling. The CBMN assay after labelling with ~290 MBq of [18F]FDG showed radiation induced inhibition of proliferation capacity of the lymphocytes, confirmed by proliferation study. CONCLUSIONS: [18F]FDG labelling of mixed leukocytes causes severe radiation damage to the cell, higher than with [99mTc]HMPAO in accordance with the absorbed dose. Labelling of mixed leukocytes for clinical purpose induces high cytotoxicity reflected in the loss of proliferation capacity in lymphocytes this statement allows us to consider a low oncogenic risk however the association between MN formation in the PBL and subsequent risk of cancer is not well established. ADVANCES IN KNOWLEDGE: This is the first work about radiation damage with [18F]FDG labelled cells. We focused on [18F]FDG labelling of leukocytes due to the growing number of research and review articles about this technique. IMPLICATIONS FOR PATIENT CARE: The possibility of an increased risk of lymphoid malignancies associated with the administration of radiolabelled lymphocytes is a very controversial subject. Studies on radiation damage on new labelling procedures as the one exposed in this work must be considered.
Subject(s)
Chromosome Aberrations/radiation effects , Fluorodeoxyglucose F18 , Leukocytes/diagnostic imaging , Leukocytes/radiation effects , Micronucleus Tests/methods , Positron-Emission Tomography/methods , Adult , Aged , Biological Assay/methods , Cells, Cultured , Dose-Response Relationship, Radiation , Female , Humans , Isotope Labeling/methods , Leukocytes/physiology , Male , Middle Aged , Radiation Dosage , Radiometry/methods , RadiopharmaceuticalsABSTRACT
To avoid adverse effects during the administration of [(123)I] meta-iodobenzylguanidine (MIBG), infusion of the drug that has been previously diluted is proposed. Stability of [(123)I] MIBG in sodium chloride solutions is studied, looking for incompatibilities in the formulation. Stability was tested on the basis of the percentage of free [(123)I] iodide on solid-phase extraction. No increase in percentages of free [(123)I] iodide was found in diluted and undiluted samples over time (P>0.05). Intravenous saline infusion of [(123)I] MIBG could be a useful tool for controlling the administration rate, minimizing the side effects and lowering the exposure of the staff to ionizing radiation.
Subject(s)
3-Iodobenzylguanidine/chemistry , Sodium Chloride/chemistry , Drug Stability , Infusions, Intravenous , Radiochemistry , Sodium Chloride/administration & dosageABSTRACT
99mTc-d,l-hexamethylpropylene amine oxime ((99m) Tc-d,l-HMPAO) is a widely used radiopharmaceutical that suffers from an inherent instability with a shelf life of 30 min that constrains its availability for clinical use. A protocol for improving the stability of the kit with minimal modification of manufacturer's instructions and no chemicals addition to the commercial formulation is proposed. The protocol is based on the displacement of the oxygen present in the preparation, preventing free radicals build up and free pertechnetate formation. Although the degradation of (99m) Tc-d,l-HMPAO cannot be explained solely by the radiolytic production of free radicals, it appears to be an important factor in the shelf stability of the complex.
