Medical Diagnosis With Radioactive Materials

Press, Volume C, Issue 29557, 5 July 1961, Page 23

Medical Diagnosis With Radioactive Materials

Medical diagnosis by radaoective materials has been rwtine foe several years at (Jhnstchurch hcapi'als but new applicadons are constantly being devetoped. Wile many of these ideas originate overseas and are check-tested in C-nnstchcrch, efty hospital laboratories ateo make extensive use of the technique m their research projects. The radioactive diagnostic ma erials used tn Chrisloburch public hospitals are issued From the isotope laboratory at the Christchurch Hospital, which is in the charge of the board’s physicist. Mr J. J. Tait The materials are mostly chemical compounds of tvpes occurring naturally in * the human body, with one of the elements of the compound present in a radioactive form. When the material is injected Into or swa&owed bv a patient, its path inside his body can be followed by tracing the disintegration of the radioactive element. In ’his way, abnormalities in the body metabolism can often be detected. The materials come from the Br itish Atomic Energy Authority's laboratories at Amersham. They are always flown out from Britain, since most of them decay verv rapidly and their useful life is seriously shortened bv any delay. In the Christchurch isotope laboratory they are kept in a special store surrounded by a thick blanket of lead and concrete to prevent radiation from harming the staff. Common ■‘Label" The mots. commonly-used radloao ive “Label” is iodine--131, which is mainly for checking the activity of the thvroid gland. Every week about eight to 10 patients are given compounds contatoiing this isotope of iodine for diagnostic purposea. In addition, an average of tour to five patients are treated with the isotope, wtoieh destroys harmful growths by giving off radiation on decay. The other main radioactive elements used for diagnosis are pbosphiorus-32. gold-196, and cobalt-00. Needles of ytrium-90 and naturallyoccurring rad on-222 are also used for treatment. A new application of radiodine, developed overseas. is in fat-absorption measurements. This has just been tested by the labora-

tory. The hospital haematology department has used cobalt--60 tor vitamin 812 investigations. iron-53 for studies of iron utilisation and the red cell uptake of iron, and chromium-51 to measure redcell survival time. Recently iodine - labelled polyvinyl perolidine enabled the staff of the full-time medical unit to diagnose a rare disorder affecting the level of albumin in the body. Also at the full-time unit, insulin containing the same

element was effective in accounting tor an unusual diabetic condition. New Equipment Nearly all these studies require a quick and easy method of measuring the radiation given off by the labelled materials on their way through the body. Instruments for this are commercially available, but are large and awkward when measurements; have to be made on bed-patients, and Mr Tait and his staff are developing a transistorised probe .which works on a lowvoltage supply. The low voltage is especially important in operating-theatre work, since a spark such as may easily be produced by high-voltage equipment is liable to explode some of the gases used in anaesthesia. The laboratory is also working on a machine for scanning a patient’s body for radioactivity. Once again, commercial equipment is on the market, but it is too large for the space available, and does not exactly meet the hospital's needs in other ways.