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Biomedical subjects

Richard Wakeford

Publications and source records attributed to Richard Wakeford.

18 recordsLinked to original sources
PubMed2004

The cancer epidemiology of radiation.

Ionizing radiation has been the subject of intense epidemiological investigation. Studies have demonstrated that exposure to moderate-to-high levels can cause most forms of cancer, leukaemia and cancers of the breast, lung and thyroid being particularly sensitive to induction by radiation, especially at young ages at exposure. Predominant among these studies is the Life Span Study of the cohort of survivors of the atomic bombings of Japan in 1945, but substantial evidence is derived from groups exposed for medical reasons, occupationally or environmentally. Notable among these other groups are underground hard rock miners who inhaled radioactive radon gas and its decay products, large numbers of patients irradiated therapeutically and workers who received high doses in the nuclear weapons programme of the former USSR. The degree of carcinogenic risk arising from low levels of exposure is more contentious, but the available evidence points to an increased risk that is approximately proportional to the dose received. Epidemiological investigations of nonionizing radiation have established ultraviolet radiation as a cause of skin cancer. However, the evidence for a carcinogenic effect of other forms of nonionizing radiation, such as those associated with mobile telephones or electricity transmission lines, is not convincing, although the possibility of a link between childhood leukaemia and extremely low-frequency electromagnetic fields cannot be dismissed entirely.

Child↗
PubMed2003

Achieving acceptable reliability in oral examinations: an analysis of the Royal College of General Practitioners membership examination's oral component.

BACKGROUND: The membership examination of the Royal College of General Practitioners (RCGP) uses structured oral examinations to assess candidates' decision making skills and professional values. AIM: To estimate three indices of reliability for these oral examinations. METHODS: In summer 1998, a revised system was introduced for the oral examinations. Candidates took two 20-minute (five topic) oral examinations with two examiner pairs. Areas for oral topics had been identified. Examiners set their own topics in three competency areas (communication, professional values and personal development) and four contexts (patient, teamwork, personal, society). They worked in two pairs (a quartet) to preplan questions on 10 topics. The results were analysed in detail. Generalisability theory was used to estimate three indices of reliability: (A) intercase (B) pass/fail decision and (C) standard error of measurement (SEM). For each index, a benchmark requirement was preset at (A) 0.8 (B) 0.9 and (C) 0.5. RESULTS: There were 896 candidates in total. Of these, 87 candidates (9.7%) failed. Total score variance was attributed to: 41% candidates, 32% oral content, 27% examiners and general error. Reliability coefficients were: (A) intercase 0.65; (B) pass/fail 0.85. The SEM was 0.52 (i.e. precise enough to distinguish within one unit on the rating scale). Extending testing time to four 20-minute oral examinations, each with two examiners, or five orals, each with one examiner, would improve intercase and pass/fail reliabilities to 0.78 and 0.94, respectively. CONCLUSION: Structured oral examinations can achieve reliabilities appropriate to high stakes examinations if sufficient resources are available.

Clinical Competence↗
PubMed2002

Childhood cancer after low-level intrauterine exposure to radiation.

Case-control studies of childhood cancer and foetal exposure to diagnostic x-rays suggest that doses as small as 10 mSv increase the risk of cancer to a detectable extent. A comparison of the risk coefficient derived from the largest such study with that obtained from the Japanese atomic bomb survivors irradiated in utero (average dose, approximately 300 mGy) shows that, once all sources of uncertainty are taken into account, these risk estimates are not incompatible. The absence of a discernible variation in the risk per unit dose over this dose range is consistent with a linear dose-response. However, uncertainties are such that definitive conclusions on the shape of the dose-response at low doses cannot be drawn from this epidemiological evidence alone. Nonetheless, the evidence does suggest that the risk is not zero at doses of the order of 10 mSv.

Case-Control Studies↗