TH-E-ValB-04: Dosimetric Impact of Changed FLT Uptake in AML Patients Treated with Chemotherapy

Autor: Robert Jeraj, M Vanderhoek, C Jaskowiak, R Pyzalski
Rok vydání: 2006
Předmět:
Zdroj: Medical Physics. 33:2290-2290
ISSN: 0094-2405
DOI: 10.1118/1.2241944
Popis: Purpose: The PETradiotracer [F‐18]FLT (3′‐deoxy‐3′‐[F‐18]fluorothymidine), used to measure cellularproliferation, has the potential to validate the efficacy of chemotherapy. We investigate the effect of chemotherapy on the biological distribution and radiationdosimetry of FLT in patients with acute myeloid leukemia (AML). Method and Materials:Cellularproliferation was measured in adult AML patients injected with 5 mCi of FLT. Dynamic and whole body PET/CT scans were acquired one day prior to chemotherapy and one week after the completion of chemotherapy using a GE Discovery PET/CT Scanner. Organs were manually contoured in the PETimages at multiple time points and time‐activity curves were generated for each contoured organ.Organ cumulative activities, organradiotracerdoses, and total body dose were determined using the standard adult male model and the RADAR method of dose calculation. Results: The biological distribution of FLT changed as a result of chemotherapy and this redistribution affected individual organ and total body radiationdoses. The toxic effect of the chemotherapeutic drugs on the leukemia cells resulted in a five‐fold reduction of FLT activity in the bone marrow post‐chemotherapy. This reduction in the bone marrow uptake was accompanied by a three‐fold increase in FLT activities and radiationdoses to the liver, kidneys, gallbladder, and adrenals while that of the spleen doubled. The total body radiationdose increased 30% post‐chemotherapy, given identical bladder voiding conditions.Conclusion: Systemic therapies such as chemotherapy can lead to significant changes in the biological distribution and dosimetry of radiotracers used in PETimaging for treatment assessment. Knowledge of these changes could impact the administered radiotracerdose to patients. Care should be taken in determining a suitable radiotracerdose for each specific case in order to avoid unnecessary dose yet maintain appropriate signal‐to‐noise ratios.
Databáze: OpenAIRE
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