The first two electron linear accelerators in South AFrica

The electron linear accelerator is considered by many leading radiotherapy centres throughout the world as the most suitable equipment for the treatment of cancer. There are good reasons for this opinion, and some physical aspects are summarised here.S. Afr. Med. J., 48, 1004 (1974)

Calibration and Measurement of Potassium-40 with a Whole-Body Counter

Total potassium content in the human body may be obtained by measuring naturally occurring radioactive potassium-40, in a whole-body counter. The basic problem in calibrating the whole-body counter is discussed, as well as a phantom that is used to solve this problem. The normal potassium levels for men and for women were determined. Two additional parameters - lean body mass and total body water - derived from the potassium content, were also calculated

Digitale Dataverwerking Gedurende Radio-isotoopflikkergrafie

The features of an on-line image data processing system for nuclear medicine are described. The uses of the system for the processing and evaluation of images, lung function determinations and cardiac studies are mentioned

Dosimetrie van Heelliggaamsbestraling met Elektrone vir die Behandeling van Mycosis Fungoides

A six-field method for whole-body radiation with 3,4 MeV electrons obtained from a Mevatron 8 linear accelerator, is described. The physical properties of the electrons are given, and a method is described whereby the wholebody isodose distributions can be predicted during wholebody irradiation

Acquisition and Processing of Cerebral Blood Flow Data with a M;ultichannel Analyser and Microcomputer

The method of the determination of cerebral blood flow in dogs with radio-isotopes to evaluate ethrane as a new anaesthetic agent is described, as well as the use of a multichannel analyser and the programmes developed for the analysis of data in a conversational mode. Preliminary results of the use of the computer programme are presented

Effect of a ripple current on the efficiency of a PEM electrolyser

The aim of this study was to determine how the efficiency of a proton exchange membrane (PEM) electrolyser is affected by an electric ripple current and the different characteristics of the ripple current (frequency, amplitude and waveform). This paper presents the experimental method and measured results, used to analyse the effect of ripple currents at various frequencies, ripple factors and waveforms on the hydrogen production, power consumption and efficiency of a PEM electrolyser. An active laboratory-size PEM electrolysis system was used to investigate the impact of various ripple currents on the efficiency of the system. The results revealed that the average power consumption increases as the ripple factor increases and decreases as the frequency of the ripple increases, while the waveform of the applied current has no effect. Furthermore, the average hydrogen flow rate is unaffected by the ripple factor, frequency or waveform of the applied ripple current

Physical Aspects of 99mTc, 87mSr and 18F for Bone Scintigraphy

The physical properties of 99mTc, 87mSr and 18F as bone scanning agents for a scintillation camera fitted with a medium energy diverging collimator, were determined. This was done by incorporating the plane source sensitivity, the modulation transfer function and the figure of merit. From the results it is clear that 99mTc is superior to 87mSr and 18F