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Biomedical subjects

E M Dean

Publications and source records attributed to E M Dean.

5 recordsLinked to original sources
PubMed1992

Output factors for blocked fields.

This study investigates the output from blocked treatment fields with 6 MV and 18 MV photons. Square fields, defined by collimators, were blocked down to smaller symmetrical square, rectangular and asymmetrical rectangular fields using blocks on a tray beneath the collimators. Up to 7.5% difference was found between the output measured for the blocked field and the output calculated using a collimator output factor for the surface field size. A method is described by which output factors for the blocked fields can be measured and used in practice. Three methods of approximating these output factors are also presented.

Humans↗
PubMed1989

Results of treatment of carcinoma of the uterine cervix using the Newcastle afterloading technique.

Eighty-seven patients with carcinoma of the uterine cervix were seen between 1 August 1977 and 31 December 1985. Seventy-one patients were treated radically. A combination of intracavitary radiotherapy, using the Newcastle manual afterloading technique, and external-beam radiotherapy was used. The actuarial 4-year survival for all Stage 1 cervical carcinomas was 84.9%. For Stage 2 cancers the actuarial local control rate was 71.1% and the survival 49.2% and for Stage 3 cancers the 4-year actuarial local control rate was 24.3% and the survival 14.8%. Complications of treatment were confined to the bowel and bladder and occurred in 11.5% of cases. The results of treatment of Stage 1 cancer suggest that the intracavitary technique gives a satisfactory distribution of radiation. The results of treatment of more advanced cases are disappointing and suggest that improvements are possible for some patients (i.e. wedge malalignment patients). There is sufficient flexibility in the technique for it to be applied satisfactorily for most anatomical situations.

Adenocarcinoma↗
PubMed1988

Gynaecological treatments using the Selectron remote afterloading system.

The Manchester method of gynaecological treatment using radium 226, ovoids and a flexible intrauterine tube has been used in many centres. In Newcastle, the Manchester technique was used until 1971, when a manually afterloaded system (MAS) using caesium 137 and two source trains was introduced. In 1985, the MAS was replaced by the Selectron remote afterloading system (RAS), which also uses caesium-137 sources. The dosimetry of this remote system has been designed to produce the same shape of isodose distributions as the MAS, but shorter treatment times. The applicator design and the dosimetry of the system used in Newcastle are discussed. Dose rates achieved by the RAS are more than double those currently produced by the MAS, and a reduction in prescribed dose of 10-20% is being made. The percentage of ward staff receiving monthly doses of more than 0.2 mSv has fallen from 78% to 18% since the introduction of the remote afterloading system. The almost-cylindrical isodose distributions facilitate matching of external beam treatments using a central lead wedge to the intracavitary treatments, and work is in progress to develop this technique.

Brachytherapy↗
PubMedDate not supplied

Stability of the human body investigated by sway magnetometry.

A new technique using a pre-calibrated magnetometer has been used to investigate the stability of the human body. Transducer coils were attached to a belt which was worn by the subject. Sway was measured over 30 s periods with eyes open and eyes closed. For 10 normal subjects, the mean sway speed was 3.6 +/- 0.9 mm/s with eyes open, and 5.3 +/- 1.5 mm/s with eyes closed. The mean ratio for eyes open to eyes closed was 0.68 +/- 0.10. The test was simple to perform and gave reproducible results.

Adult↗