Medical Imaging Research unit
Current projects
Low
dose digital X-rays for primary health care
Over
the past decade, De Beers has developed an internationally patented digital
X-ray technology which uses an extremely low dose (less than 20% of conventional
X-rays), yet provides extremely high resolution images. The prototype system,
called LODOX, has recently been installed at Groote Schuur Hospital.
There are two primary
purposes to this project:
- to develop the algorithms
to generate computer tomographic images based on a limited number of angles;
and
- to utilise LODOX as
a population screening instrument for diagnosing tuberculosis and other
diseases visible in the chest.
The project is being run
by a joint venture consortium called African Medical Imaging (Pty) Ltd in
which the three shareholders are UCT, De Beers and the National Accelerator
Centre.
An
interactive image-guided surgical navigator
In order
to remove deep-lying tumours from the brain with minimal damage to surrounding
tissues, it is essential to locate intra-operatively the position of the tip
of the neurosurgeon's probe relative to the position of the lesion, as determined
pre-operatively using an imaging modality such as computed tomography (CT)
or magnetic resonance imaging (MRI).
A prototype surgical navigator
has been developed that determines the position of the tip of the surgical
probe during surgery by measuring remotely the positions of precisely calibrated
markers arranged on the probe. The position of the tip is displayed on the
nearest CT or MRI slice.
This project aims to develop
the prototype navigator into a commercially viable system.
Telemedicine
for rural hospitals and clinics
The relatively
well-developed information and communications technology (ICT) infrastructure
of South Africa, combined with sparse medical services in rural communities,
makes our country an ideal venue for implementing and evaluating telemedicine.
This project has three
phases:
- to assess the needs
of outlying communities and their potential to benefit from telemedicine
links with the MRC/UCT Medical Imaging Research Unit;
- to develop and refine
a local multipurpose telemedicine link using off-the-shelf software components
on a standard hardware platform; and
- to perform an audit
of the achievements of the project, with special focus on cost-effectiveness.
Functional
brain imaging using high-resolution EEG
High
resolution electroencephalography (HR-EEG) provides a powerful tool that overcomes
the poor temporal resolution of traditional functional brain imaging methods
(e.g. positron emission tomography and magnetic resonance imaging).
Using an HR-EEG system
with 128 channels, we plan:
- to investigate the
patterns of functional coupling within the neocortex during the performance
of motor acts; and
- to evaluate the use
of non-invasive HR-EEG imaging to locate the sites of epileptogenic tissue
in epileptic patients.
In project one we are
interested in the role of the brain in fatigue during exercise, while in project
two we will compare HR-EEG and intra-operative subdural recording.
Understanding
the connection between electromagnetic fields and cancer
In recent
years there have been several reports based on epidemiological and experimental
animal studies that suggest a possible carcinogenic effect of extremely low
frequency electromagnetic fields emitted from power lines, computers, televisions,
microwave ovens and cellular telephones.
On the other hand, some
studies suggest a possible anti-carcinogenic effect of constant magnetic fields.
We intend to try and confirm
these reports and to explain the basic mechanisms involved in the biological
effects of these two types of fields. In all cases, we believe changes in
the cell membrane will occur (e.g. substitution of antigens and alterations
in adhesive properties). We will use different medical imaging approaches
to study the cell morphology and ionic concentration, including electron microscopy
and computerised fluorescence microscopy.
Video-based
measurement of neuromuscular function
One of
the ways to characterise neuromuscular function is through video-based measurement
of a person's movement. Four subject groups are being evaluated:
- normal children, aged
12 to 48 months, who are acquiring locomotor skills;
- children with cerebral
palsy who are undergoing various forms of treatment (e.g. muscle strengthening
or neurosurgery);
- athletes who have
suffered a partial or complete tear of their anterior cruciate ligament
in the knee; and
- normal subjects who
are studied while exercising to fatigue.
This project has an important
link with a research group at University College Dublin in Ireland that is
financed by the Wellcome Trust.
Accurate
positioning of patients for proton therapy
The medical
user group at the National Accelerator Centre currently treats patients with
brain tumours using high energy protons. Uising the Bragg effect, these protons
are localised very successfully on the target lesion provided the patient
can be accurately positioned.
This project has two main
thrusts:
- to improve the current
method of measuring the 3D position of the tumour relative to the external
coordinate system; and
- to incorporate an
industrial robot arm for positioning the patient in the proton beam so that
lesions in the rest of the body can also be treated.
A
new screening method for fetal alcohol syndrome
Fetal
alcohol syndrome (FAS), which occurs as a consequence of excessive maternal
alcohol ingestion during pregnancy, is the most common cause of preventable
mental retardation worldwide.
Previous studies have
shown that in the disadvantaged communities of the Western Cape the prevalence
of FAS exceeds by 35 times that of First World Nations.
The diagnosis of FAS requires
intensive specialist participation, making it a costly procedure.
Using a stereo-videometric
approach, this study aims to provide a cost-effective and easily employed
tool for the rapid evaluation of populations at risk for FAS, thus allowing
the need for, and effects of, preventative measures in communities to be rapidly
assessed. |
