| Abstract | In the field of nuclear medicine the value of the pulse-height spectrometer is now well recognized. Given an alert and informed operator, it can reduce the obscuring effects of background; it can at least partially suppress unwanted scattered radiation; it can provide better stability (other things being equal) than is available in a "threshold" counter; it can check the radiochemical purity of a questionable drug; and often it can measure separately two radioactive components in the same sample. The persistent demand for still lower radiation doses to the patients, and the development of new, low-energy emitters, have created new difficulties for the counting equipment, and skillful operation is more important than ever. Good counting efficiency is hard to obtain, and the factors that determine it should be well understood if weak samples are to be counted. The selection of the spectrometer's energy band depends on resolution, as well as on other things. The counting of large, weak samples, and of whole patients, brings up a number of difficult problems, and calls for an all-out attack on background. |
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