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Biomedical subjects

K E Halnan

Publications and source records attributed to K E Halnan.

At least 19 recordsLinked to original sources
PubMed1992

The Hong Kong Academy of Medicine.

The Hong Kong Academy of Medicine is being founded this year. This brief article gives something of the background, structure and function of the Academy.

Academies and Institutes↗
PubMed1985

Radio-iodine treatment of hyperthyroidism--a more liberal policy?

The main and most valid evidence we have is that on direct follow-up of treated patients. This has been well done in thousands of patients in two countries with very good medical care and over long periods--10 to 15 years or more. On the other hand there is no doubt about radiation carcinogenesis, and thyroid cancer has been caused in children by low-dose x-ray therapy. The possibility of other cancer and of leukaemogenesis is also real. The evidence for this is reviewed and risk estimates given. Experimental work and radiation biology is reviewed and it is suggested that the risk of thyroid cancer from the usual radio-iodine doses given for treatment is low because of cell killing or sterilization, and animal evidence is discussed that supports this. The final position appears to be that no risk has yet been demonstrated in man and evidence in general suggests that if there is indeed a cancer risk it will be less than about 0.1%. It is suggested that this is not dissimilar to surgical risks, except that these are more immediate as compared with the long latent period for development of radiation-induced cancer. Genetic risks are also discussed and again have not been demonstrated in man from this treatment and should in any case be low. The risk to children is also considered; there is no direct evidence of risk but only small numbers have been treated--nevertheless the hypothetical risk may be counterbalanced by the benefits. Administration of radio-iodine therapy to pregnant or lactating women must be scrupulously avoided; both cause significant risks. Finally, if a more liberal policy be accepted it is worth while giving optimum treatment, and evidence is given suggesting low-dose treatment similar in effect to surgical thyroidectomy and followed temporarily if need be by anti-thyroid drug treatment.

Abnormalities, Radiation-Induced↗
PubMed1985

Blood flow and oxygen utilisation in the contralateral cerebral cortex of patients with untreated intracranial tumours as studied by positron emission tomography, with observations on the effect of decompressive surgery.

Using positron emission tomography, regional cerebral blood flow and oxygen utilisation were measured in the contralateral cortex of 14 patients with a variety of intracranial tumours. A comparison was made with cortical values derived from 14 normal controls. Compared with normal subjects, patients with brain tumours had a significant reduction in oxygen utilisation and blood flow in their contralateral cortex. Decompression resulting from craniotomy and biopsy, led to a partial reversal of this cerebral hypofunction.

Adult↗
PubMed1978

Hyperbaric oxygen and radiotherapy: a Medical Research Council trial in carcinoma of the cervix.

In a randomized controlled clinical trial of hyperbaric oxygen in the radiotherapy of advanced carcinoma of the uterine cervix a total of 320 cases were contributed by four radiotherapy centres in the United Kingdom. The use of hyperbaric oxygen resulted in improved local control and survival. The benefit was greatest in patients under the age of 55 who presented with stage III disease. There was a slight increase in radiation morbidity but it seemed that the benefit of hyperbaric oxygen outweighed this increase in morbidity and that there was a true improvement in the therapeutic ratio.

Adult↗
PubMed1976

A comparison of physical and cytogenetic estimates of radiation dose in patients treated with iodine-131 for thyroid carcinoma.

Physical and cytogenetic estimates of the whole-body radiation doses have been compared in 11 patients receiving large doses of iodine-131 for the treatment of thyroid carcinoma. The physical estimate was based on the measurement of thyroid uptake, of the plasma activity variation, and of urinary activity. The cytogenetic estimate was obtained from the analysis of chromosome aberrations in peripheral blood lymphocytes. Good agreement between the estimates was observed in patients whose thyroid glands had previously been ablated by radioiodine. In patients who had varying degrees of thyroid function, there were considerable differences between the estimates with the cytogenetic value always being higher. It is suggested that these differences might be due in part to non-uniform irradiation of lymphocytes by local sources of activity in the thyroid and in the liver.

Body Burden↗