The Use of Isotopes in Haematology [antikvár]

INTRODUCTION It is just over 35 years ago that Hevesy's classical experiments introduced the use of radioactive isotopes into biological research. Radioactive 'labelling' has opened a great vista of new fields; problems before unassailable were solved with this new approach. Today, it is difficult to find an issue of a journal of the biological sciences which would not contain a publication using radioactive 'tracer' material. From the research field, the application of radioactive labelling has passed speedily into clinical use. Apart from clinical research problems the labelling methods have offered significant advances in the diagnosis of diseases. Nowadays, very justifiably, most major hospitals have their isotope laboratories, some centralized, some spread over various departments. Simple as the principle of radioactive labelling is, in practice, every isotope work requires a team of skilled specialists. This aspect is, in fact, one of the gratifying characteristics of isotope work. A combination of various disciplines (physicists, chemists, biologists, clinicians) is not only refreshingly cross fertilizing by their different approaches to problems, but is capable of attacking problems otherwise beyond the reach of any one of these disciplines. While this aspect of isotope work makes it very attractive in studying divers clinical problems, it must be remembered that application of radioactivity involves a certain dose of ionizing radiation to parts or to the whole of the body. In most instances the radiation doses involved are relatively small, but in any routine method involving an appreciable proportion of human population the advantages of a method involving radiation and the disadvan- tages of a dose of radiation have to be weighed carefully. This is not always as easy as it is in the case of diagnostic radiology. The radiation doses delivered with the present accepted clinical diagnostic applications of radioactive isotopes are much smaller than the smallest radiation doses which can produce measurable somatic effects in experimental animals. More caution is needed, however, in considering a possible genetic injury (persons in the reproductive age group), although again the effects of usual isotope procedures at present are too small to be measurable. Indiscriminate use of radio- active materials is therefore to be avoided, but where there is reason to hope to gain useful information, their use is perfectly justifiable. ix