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15 September 2022 | Story André Damons | Photo André Damons
Dr Osayande Evbuomwan, Prof Willy Vangu and Dr Gerrit Engelbrecht
Dr Osayande Evbuomwan, nuclear medicine specialist and Senior Lecturer, left, and Dr Gerrit Engelbrecht, Clinical Head of the Department of Nuclear Medicine at the UFS, right, with Prof Willy Vangu, Chief Specialist and Head of Nuclear Medicine at the University of the Witwatersrand, after his lecture.

There is no doubt that an institution like the University of the Free State (UFS), with its calibre and pedigree, needs a PET/CT machine (medical-imaging device that simultaneously and clearly reveals both anatomical details and metabolic processes within the body), particular in oncology, in improving the management of patients. 

This is according to Prof Willy Vangu, Chief Specialist and Head of Nuclear Medicine at the University of the Witwatersrand, who was a guest lecturer on 8 September 2022 at the Department of Nuclear Medicine at the UFS.

Positron emission tomography (PET) is a type of nuclear medicine imaging modality that measures the metabolic activity of the cells of body tissues. PET imaging is useful in the evaluation of patients with neurological, cardiac, infection, inflammation, and most importantly oncological conditions. Through its ability to detect metabolic changes very early, it can detect disease conditions that might not be easily detected on other forms of anatomical imaging.

Role of PET/CT in different clinical scenarios

In his lecture, Prof Vangu talked about the role of PET/CT in different clinical scenarios. By giving practical examples, he explained the role of PET/CT in different aspects of clinical medicine, including brain imaging for dementia, movement disorder and cerebrovascular reserve. 

“Looking at dementia, we will focus on one of diseases that is today becoming a major source of health concern, Alzheimer's disease. The latest Alzheimer's report that was published in 2018 stated that there are 50 million individuals currently suffering from Alzheimer's. They forecast that in 30 years we are going to have more than 150 million people suffering from this disease. PET/CT imaging can identify very early the typical patterns associated with all the different types of dementias, including Alzheimer's disease…”

For cardiac application, Prof Vangu said there are so many indications for PET/CT in cardiac imaging. One of the most important is the assessment of myocardial viability, in patients who have suffered from cardiomyopathy due to ischemic heart disease. PET/CT offers a noninvasive method of identifying viable myocardium that would benefit from revascularisation, with a very high diagnostic accuracy. 

Prof Vangu, who is also the head of nuclear medicine at the Charlotte Maxeke Johannesburg Academic and Chris Hani Baragwanath hospitals as well as head of the department for radiation sciences at the University of the Witwatersrand, said PET has been around for many years and is not something new. However, in clinical practice, PET imaging became significant with a breakthrough that occurred with the production of the glucose analogue tracer, 18F-fluorodeoxyglucose (FDG). This tracer in PET/CT imaging has revolutionised the management of cancer patients for the oncologist. It offers the ability of more accurate cancer staging, assessment of treatment response, assessment of disease recurrence and in some situations, surveillance. It has the ability to predict early which cancer patients will benefit from a particular drug, thereby giving the oncologist an idea on either to de-escalate treatment or change to a second line regimen very early on in the management. 

PET-CT scan imaging machine

An internet example of an image taken by a PET/CT machine. Photo for illustration: A PET/CT Imaging machine.


PET/CT came onto the market only in the year 2001, when it was launched for the first time by David Townsend (a physicist) and Ronald Nutt (electrical engineer). As at today, almost every institution in the country has at least one PET/CT machine.


“Looking at clinical applications, which is really the crux of the lecture today, there are so many clinical applications to talk about. You need a full week of a PET/CT symposium to go through all of them (and) maybe that might not even be enough. We can at least from this talk have an idea on how PET/CT can be applied in clinical medicine,” said Prof Vangu.

No other road for the university but to get a PET/CT machine

He also showed the impact and results that PET/CT imaging had in the management of infection and inflammation including TB. He said the role of PET/CT in TB is for monitoring of treatment, identification of extrapulmonary TB and prognosis. 

In concluding his lecture, he said there is no other road for the university but to get a PET/CT machine. “There is no argument about it. The institution needs it to improve the management of patients, especially the oncology and cardiology patients. Confidently making the decision on which patients to treat, how to treat them, identifying and evaluating their true response to therapy requires a PET/CT machine.

“I am happy to hear that the policy- and decisions-makers in the province and the university are looking forward to having a PET/CT machine,” he said later. 

Dr Osayande Evbuomwan, nuclear medicine specialist and Senior Lecturer, and Dr Gerrit Engelbrecht, Clinical Head of the Department of Nuclear Medicine at the UFS, are both looking forward of having a PET/CT in the department because in addition to its use in clinical setting, it has a huge role to play in research and training postgraduate students, as PET/CT imaging makes up a huge chunk of the postgraduate training curriculum

News Archive

Well-established root system important for sustainable production in semi-arid grasslands
2015-02-24

Plot layout where production and root studies were done
Photo: Supplied

The importance of a well-established root system for sustainable production in the semi-arid grasslands cannot be over-emphasised.

A study of Prof Hennie Snyman from the Department of Animal and Wildlife and Grassland Sciences at the University of the Free State is of the few studies in which soil-water instead of rainfall has been used to estimate above- and below-ground production of semi-arid grasslands. “In the past, plant ecological studies have concentrated largely on above-ground parts of the grassland ecosystem with less emphasis on root growth. This study is, therefore, one of the few done on root dynamics in drier areas,” said Prof Snyman.

The longevity of grass seeds in the soil seed bank is another aspect that is being investigated at present. This information could provide guidelines in grassland restoration.

“Understanding changes in the hydrological characteristics of grassland ecosystems with degradation is essential when making grassland management decisions in arid and semi-arid areas to ensure sustainable animal production. The impact of grassland degradation on productivity, root production, root/shoot ratios, and water-use efficiency has been quantified for the semi-arid grasslands over the last 35 years. Because of the great impact of sustainable management guidelines on land users, this study will be continuing for many years,” said Prof Snyman.

Water-use efficiency (WUE) is defined as the quantity of above- and/or below-ground plant produced over a given period of time per unit of water evapotranspired. Sampling is done from grassland artificially maintained in three different grassland conditions: good, moderate, and poor.

As much as 86, 89 and 94% of the roots for grasslands in good, moderate and poor conditions respectively occur at a depth of less than 300 mm. Root mass is strongly seasonal with the most active growth taking place during March and April. Root mass appears to be greater than above-ground production for these semi-arid areas, with an increase in roots in relation to above-ground production with grassland degradation. The mean monthly root/shoot ratios for grasslands in good, moderate, and poor conditions are 1.16, 1.11, and 1.37 respectively. Grassland degradation lowered above- and below-ground plant production significantly as well as water-use efficiency. The mean WUE (root production included) was 4.79, 3.54 and 2.47 kg ha -1 mm -1 for grasslands in good, moderate, and poor conditions respectively.

These water-use efficiency observations are among the few that also include root production in their calculations.

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