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Applications of optically-based
techniques in surgery and medicine continues to increase
rapidly. This is mainly due to the fact that such techniques
hold a series of inherent advantageous properties compared
to more conventional medical techniques. For instance, by
applying optical techniques, treatments and diagnostic procedures
can be done non-invasively, which reduces the inconvenience
for the patients as well as the risk of spreading infectious
diseases. Furthermore, optically-based medical equipment
is on average relatively inexpensive and can also be made
transportable, allowing for outpatient treatment and early
diagnostics at first level patient care. This is of course
of substantial importance with regards to South African
conditions, e.g. deployment of medical diagnostic and therapeutic
equipment in remote and rural areas.
Examples of optically based medical applications
are:
- Phototherapy (i.e. photodynamic cancer therapy (PDT)
and low-level laser therapy (LLLT).
- Laser surgery (in ophthalmology, dermatology, oncology,
cardiology)
- Optical biopsy (i.e. cancer diagnostics, tissue glucose
measurements, and hemodynamic monitoring)
- Optical tomography (i.e. optical coherence-, photo-acoustic-,
fluorescence-, and time-resolved transmittance tomography)
The biophotonics group at the CSIR National
Laser Centre is involved in projects on both PDT and LLLT.
To facilitate these and future projects the group is in
the process of completing a generic in-house platform for
pre-clinical testing of novel optically based medical applications.
As illustrated in the figure below, this so-called Biomedical
Optics Test Bed (BioBed) platform consists of four core
technologies:
Tissue spectroscopy: Fundamental
optical characterisation of biological media, i.e. determination
of absorption and scattering properties of human tissue,
and body fluids.
Photon migration modelling and analysis: Mathematical
modelling and computer simulations of light propagation
in human tissue as well as multivariate data analysis.
Tissue-simulating phantoms: Manufacture and assembly
of liquid and molded solid phantoms for reference and control
as well as artificial (living) human tissue equivalents
for preclinical testing.
Multimodal optical tomography: Non-invasive (and
non-ionising) imaging/morphological analysis of human tissue
in order to monitor and quantify the structural effects
of optically based therapeutic modalities applied, and to
aid in the development of novel medical diagnostic techniques.
To implement the BioBed platform at the CSIR, a biological
cell culture laboratory has been established and closely
integrated with adjacent optical laboratories. This enables
the biophotonics research group to manufacture synthetic
three-dimensional (3D) tissue models from human cell samples,
which can be induced with various forms of lesions, e.g.
cancer. Consequently, these 3D tissue models constitute
a very convenient, cost-effective, and realistic - but risk-free
- environment for preclinical testing and optimisation of
novel medical laser applications. To monitor and quantify
the effects of various optically-based medical therapeutic
modalities, a so-called optical coherence tomography
(OCT) system has also been acquired. This OCT system allows
scientists to perform non-invasive in vivo cross-sectional
real-time imaging of living tissue. In the case of skin
tissue (as shown in the figure), the OCT system will provide
images with a resolution of ~ 10 µm down to a depth
of ~ 3 mm.
The BioBed R&D platform at the CSIR National
Laser Centre
As implied above, the field of biomedical
optics is highly multidisciplinary. Therefore, to succeed,
collaboration between various disciplines, for example physics,
medicine, biology, and engineering is crucial. Accordingly,
one of the key drivers for establishing the BioBed platform
was to facilitate such multidisciplinary biomedical optics
collaboration in South Africa. A number of such projects
have already been launched.
Researchers
Jan S Dam: biophotonics research group leader
Aletta Karsten: modeling of laser tissue interaction for therapeutic applications as well as optical coherence tomography
Patience Mthunzi: pursuing a PhD degree at the Optical Trapping Group at the University of St. Andrews, UK.
Ann Singh: biophotonics, specifically those areas which can yield an improvement in the quality of life, both environmental and human.
Ivy Ndhundhuma: developing a 3D-skin tissue model to be used as an important tool in the ongoing laser-tissue interaction studies of the group.
Interested companies, research institutions
or students with ideas on other new potential collaboration
projects are encouraged to contact research group leader,
Dr Jan Dam for further
discussions and exploration.
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