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Biomedical subjects

S E Griffiths

Publications and source records attributed to S E Griffiths.

15 recordsLinked to original sources
PubMed1996

In the middle of the night.

Early morning emergency calls are varied and challenging. They raise issues about clinical care, payment of country doctors, interaction with the healthcare team and the philosophy of care.

Emergencies↗
PubMed1991

Quality control of radiotherapy during pelvic irradiation.

For 20 patients undergoing pelvic irradiation, various set-up methods were compared for accuracy of field placement. The overall incidence of errors on 294 fields checked was lower (p less than 0.001) than that in a previous study. A standard deviation of 1.5 mm for lateral placement accuracy was obtained.

Carcinoma↗
PubMed1987

Quality control in radiotherapy: the reduction of field placement errors.

A 'blind' study using treatment verification films has been performed on two series of patients to assess the accuracy of placement of complex infradiaphragmatic fields planned to include para-aortic nodes. Sequential verification films (VF) for each field on all patients studied were compared to determine variations in field position relative to the anatomy, especially lymph nodes, and the simulator plan. Nodes included in the plan but partially or completely missed by one or more treatments were identified, as were the error types involved. In series I, 21% of 157 VF showed a nodal miss, and after changes in practice designed to minimize the error types responsible for those, the figure was reduced in series II to 5.5% of 194 VF. In series II a 50% reduction in magnitude of the average systematic lateral shift and rotation of posterior fields is attributed mainly to the discontinuation of the practice of treating posterior fields through the couch. Apart from a prescribed width of less than 9 cm, three quantitative key factors were derived: greater than 6 mm lateral shift, greater than 7 mm field narrowing, 2 degree or more rotation of fields. The correction of these errors if identified on verification films, should eliminate the subsequent occurrence of node misses. The value of routine clinical treatment verification films at the start of treatment to identify and correct systematic errors is emphasized, as is the importance of precise and standardized technical practice.

Humans↗
PubMed1986

The daily reproducibility of large, complex-shaped radiotherapy fields to the thorax and neck.

A series of patients treated with complex fields to the thorax and neck utilising individually tailored shielding blocks made from low-melting-point alloy (LMPA), were investigated using treatment verification film to identify field placement errors. A total of 19 patients yielded 171 machine verification films, which were analysed. It was found that on 21% of occasions the intended treatment volume was partially shielded, by more than 1 cm, by the lead blocks prescribed to protect the lungs. On half of these occasions (11% of the total), the areas erroneously shielded contained known disease. Suggestions are made for minimising such errors in the future.

Head and Neck Neoplasms↗
PubMed1985

The impact of treatment errors on post-operative radiotherapy for testicular tumours.

Twenty-four patients receiving post-operative radiotherapy for testicular tumours have been studied to assess the impact of treatment errors. Regular treatment verification radiographs were performed and compared with simulator planning radiographs. It was demonstrated that lymph nodes in the area most at risk, i.e., para-aortic nodes at L1 to L3 on the ipsilateral side, were inadequately irradiated on 10% of treatments, and that at least one lymph node miss was recorded in 12 of the 24 patients. These results are considered to be a minimum estimate. Mostly para-aortic fields 8.0 cm wide were used, but it was shown that the number of lymph-node misses could have been substantially reduced by using fields 9.0 cm wide, whilst the consequent increase in irradiated kidney volume was considered acceptable.

Dysgerminoma↗
PubMedDate not supplied

The dopamine D2 receptor C32806T polymorphism (DRD2 Taq1A RFLP) exhibits no association with smoking behaviour in a healthy UK population.

A single nucleotide polymorphism (SNP) in the Taq1A site near the DRD2 gene has been associated in several studies with smoking behaviour. We genotyped 732 current smokers (241 low, one to nine cigarettes a day, 250 mid, 10-19 cigarettes, 241 high, 20+cigarettes) and 243 never-smokers at this site (C32806T), to test for effects on smoking initiation and amount of tobacco consumed. No significant association between minor allele frequency and smoking status was detected. Multiple regression analysis including DRD2 genotype, sex, age and alcohol consumption as predictors showed that level of cigarette consumption was associated with sex (p=0.003) and age (p=0.002) but not with alcohol consumption (p=0.25) or DRD2 genotype (p=0.76).

Adult↗
PubMedDate not supplied

The reproducibility of large lead protected radiotherapy fields to the abdomen and pelvis.

A series of patients treated with large, lead protected, abdomino-pelvic fields have been investigated, to identify field placement errors. Two hundred and forty-three machine verification films were performed on a total of 33 patients, and the films analysed. Important errors were detected resulting from field rotation, lateral shift and field width variations. Suggestions are made as to how these errors may be minimised in the future.

Abdomen↗