NUKLEONIKA 2012, 57(4):607-613

 


BIOKINETICS AND RADIATION DOSIMETRY FOR [4-14C] CHOLESTEROL IN HUMANS



Larissa A. Marcato, Margarida M. Hamada, Carlos H. de Mesquita

Brazilian National Nuclear Energy Commission (CNEN/SP),
Institute for Nuclear and Energy Research (IPEN), Radiation Technology Center (CTR),
2242 Prof. Lineu Prestes Ave., – Cidade Universitαria, 05508-000, Sao Paulo – SP, Brazil

This study proposes a biokinetic model for using in the assessment of the internal dose received by human subjects administered intravenously or orally with [4-14C]-cholesterol. The proposed model includes three systemic pools representing the short-term (T1/2 = 1 d), intermediate-term (T1/2 = 16 d) and long-term (T1/2 = 78 d) physiological exchanges and two excretion pathways: urine and feces. To validate the model, the predicted excretion and absorption of cholesterol was compared with that described in the literature. The radiometric doses were calculated in function of the phantom body mass (M) applying MIRD (medical internal radiation dose) protocol with ANACOMP software. The effective dose coefficients for oral administration were: 2.93 Χ 10–10 Sv.Bq–1 (73.3 kg); 3.84 Χ 10–10 Sv.Bq–1 (56.8 kg); 6.74 Χ 10–10 Sv.Bq–1 (33.2 kg) and 7.72 Χ 10–10 Sv.Bq–1 (19.8 kg). To determinate the dose for intermediate body mass M the polynomial interpolation can be used: Sv.Bq–1 (kg) = 6 Χ 10–15M3 – 8 Χ 10–13M2 + 2 Χ 10–11M + 6 Χ 10–10 (R2 =~ 1). In the same way, for intravenous administration were: 3.72 Χ 10–10 Sv.Bq–1 (73.3 kg); 4.87 Χ 10–10 Sv.Bq–1 (56.8 kg); 8.49 Χ 10–10 Sv.Bq–1 (33.2 kg); 1.26 Χ 10–9 Sv.Bq–1 (19.8 kg). Similarly, for any M body mass: Sv.Bq–1 (kg) = –4 Χ 10–15M3 + 9 Χ 10–13M2 – 7 Χ 10–11M + 2 Χ 10–9 can be used.

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