Quality control radioisotope methods

Some of the intended categories of use of radioisotopic reference material have been reviewed recently by Fajgelj et al. (1999). They include assignment of property values, establishing the traceability of a measurement result, determining the uncertainty of a measurement result, calibration of an apparatus, assessment of a measurement method, use for recovery studies and use for quality control purposes. It should be noted however that, in general, natural matrix reference materials are not recommended for calibration purposes. This should preferably be done with pure chemical forms of the element labelled with the isotope of interest. Calibrated isotopic sources of this kind are available from a number of commercial suppliers and are not the subject of this review. 

FDNB on the skin. The other methods are on the other hand relatively simple and rapid, their assay procedures taking 1,5 - 2 h to complete. The succinic anhydride method does however have the problem of requiring radioisotope facilities, which could limit its use in the typical quality control laboratory. 

Zambia, Thailand and USA (Florida) were analyzed by using the X-ray fluorescence method for elemental composition. These rock phosphates have also been evaluated for their agronomic effectiveness by means of radioisotope techniques (Zapata and Axmann, 1991). The samples were prepared as pellets and analyzed using the emission transmission method for trace elements (Markowicz and Haselberger, 1992). All samples were excited using an Mo tube with an Mo secondary target. For quality control of concentration data analysis of standard reference material CRM 032 (phosphate rock) produced by CEC, Brussels, has been used. Satisfactory agreement between certified and measured values was obtained. 

For developing these comparative laboratory methods, the lead molecule selected by the participants in the present CRP was [DOTA°,Tyr ]-octreotate (DOTATATE) and the mostly widely used radioisotope was Lu. Consequently, one of the achievements of the CRP was the development of Lu-DOTATATE as a viable product for therapy. This chapter describes the considerations that led to the development of Lu-DOTATATE and provides the details of its preparation and quality control. This protocol could be adapted for preparation and quality control of the product for clinical use. 

Quality control laboratories should be separated from production areas. Areas where biological, microbiological, or radioisotope test methods are employed should be separated from each other. 

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