Standardization Of 125I Research Articles

The standardization methods of radioactive sources (125I, 131I, 99mTc, and 18F) for calibrating nuclear medicine equipment in Indonesia

The standardization of radioactive sources (125I, 131I, 99mTc and 18F) to calibrate the nuclear medicine equipment had been carried out in PTKMR-BATAN. This is necessary because the radioactive sources used in the field of nuclear medicine has a very short half-life in other that to obtain a quality measurement results require special treatment. Besides that, the use of nuclear medicine techniques in Indonesia develop rapidly. All the radioactive sources were prepared by gravimetric methods. Standardization of 125I has been carried out by photon- photon coincidence methods, while the others have been carried out by gamma spectrometry methods. The standar sources are used to calibrate a Capintec CRC-7BT radionuclide calibrator. The results shows that calibration factor for Capintec CRC-7BT dose calibrator is 1,03; 1,02; 1,06; and 1,04 for 125I, 131I, 99mTc and 18F respectively, by about 5 to 6% of the expanded uncertainties.

Standardization of125I by the sum-peak method and the results of a bilateral comparison between ENEA (Italy) and INP (Albania)

An intercomparison on absolute activity measurements of125I sources by the sumpeak method was carried out in 1993 between the Primary Standard Laboratories for Ionizing Radiations of Italy (ENEA) and Albania (INP). The sources were prepared by ENEA starting from a125I solution. The sources were measured at ENEA and successively at INP. The results were in good agreement, the deviation of the INP results from the ENEA results being about −0.5% with an overall uncertainty of both results about 0.3% (1σ). This paper describes the instrumentation and the experimental procedures used in this comparison by the two Institutes.

The standardization of 125I: a comparison of three methods

Three methods of standardizing 125I have been compared: (1) sum-peak coincidence counting with a Ge detector, (2) X-ray-X-ray coincidence counting, and (3) 4πe-X coincidence counting with efficiency extrapolation. The object of the study was to look for any evidence at the 0.1% level of systematic differences in the derived activity concentration. Enough data were accumulated to reduce the statistical uncertainties for methods (2) and (3) to 0.05%. It is concluded that systematic differences, if any, between the results of the methods are ≤ 0.2%.

Standardization of 125I by photon-photon coincidence counting and efficiency extrapolation

The standardization of 125I by photon-photon coincidence counting and the determination of the activity by a linear efficiency extrapolation is described. The variation of the efficiencies is realized by symmetrically changing the distance between the source and two movable photon detectors with thin NaI(Tl) crystals. Experimental results, data evaluation and the accuracy of the method are discussed.

Qualitative and quantitative measurements of radioiodines

Some methods for measurements of radioiodines are discussed. Three isotopes of iodine are presented in detail;125I,129I and131I. Limited discussions of123I and126I are also given. Measurements of these isotopes are examined for both the NaI(TI) and liquid scintillation systems. The properties of the decay schemes are utilized to explain the mode of measurements of the isotopes in these two types of detectors. Methods of standardization of the radioiodines are discussed. Special emphasis is given to the direct standardization of125I as compared to so called “Mock125I” standards.

Qualitative and quantitative measurements of radioiodines

Some methods for measurements of radioiodines are discussed. Three isotopes of iodine are presented in detail;125I,129I and131I. Limited discussions of123I and126I are also given. Measurements of these isotopes are examined for both the NaI(TI) and liquid scintillation systems. The properties of the decay schemes are utilized to explain the mode of measurements of the isotopes in these two types of detectors. Methods of standardization of the radioiodines are discussed. Special emphasis is given to the direct standardization of125I as compared to so called “Mock125I” standards.