Medical Radiology and Radiation Safety. 2014. Vol. 59. No. 3. P. 45-51


A.V. Khmelev1, P.S. Bakay2

Study of the 124I Cyclotron Production Parameters Impact for its Activity and Radionuclide Purity

1. Russian Medical Academy for Postgraduate Education, Moscow, Russia. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. ; 2. N.N. Blokhin Russian Cancer Research Center of RAMS, Moscow, Russia


Purpose: Definition of terms wherein cyclotron-produced 124I applicable for using in PET-diagnostics in oncology.

Material and methods: Numerical simulation of 124I production process in nuclear reactions initiated in the target TeO2 by 10–15 MeV proton beam as well as such reaction products decay was carried out.

Results: It is shown that 124I activity gains the maximal value (86 mCi) at proton energy E = 12 MeV (for “beam current (I) × irradiation time” (t0) parameter equaled 100 m A×hour) and it decreases on ~ 10 % at grow of 123Te impurity concentration in the target from 0.5 up to 10 %. Existence of time span after the end of the target irradiation wherein produced 124I satisfy to radionuclide purity and activity requirements for application in PET-diagnostics was found. Beginning of this time span depends on proton energy and concentration of impurity 123Te (Ki). 124I has become applicable in 2.1–8.3 days from the end of irradiation at energy changing in the range of 10–15 MeV. Beginning of time span grows from 4.7 days up to 5.1 days at Ki increasing from 0.5 up to 10 % at E = 12 MeV and It0 = 100 μAhour. 124I application time grows with increasing of It0. This time also depends on proton energy and it gains the maximal value of 15.2 days at E = 11 MeV and It0 = 100 μAhour.

Conclusion: Radionuclide purity and activity of 124I are determined by parameters of its cyclotron production – beam current, target irradiation time and proton energy as well as 123Te impurity concentration in the target and time from the end of the irradiation. Dependences of the beginning and duration of time span of cyclotron produced 124I for its application in PET-diagnostics from these parameters are established and studied.

Key words: cyclotron, 124I radionuclide, activity, radionuclide purity