Radiation detectors for error free radiation therapy
Professor Anatoly Rozenfeld and his team at the Centre for Medical Radiation Physics, University of Wollongong, have been looking at new ways to improve quality assurance for radiotherapy.
In recent years, there have been exciting developments in
radiation treatment.
New technologies have been developed that can deliver higher
doses of radiation to a more defined area, and with great accuracy.
Treatments such as Intensity Modulated Radiation Therapy (IMRT),
Stereotactic Radiosurgery (SRS), Image Guided Radiotherapy (IGRT);
and more recently, Volumetric Modulated Arc Therapy (VMAT), the
Gamma Knife and Tomotherapy have all led to improved outcomes for
patients.
However, with each new advance radiation therapy becomes more
complex, which means clinicians need to be certain about their
treatment plan for each patient.
Professor Anatoly Rozenfeld and his team at the Centre for
Medical Radiation Physics, University of Wollongong, have been
looking at news ways to improve quality assurance for
radiotherapy.
As he explains it: "The complexity of real-time radiotherapy,
including the reduced time to detect errors (sub-second) and
increased reliance on automated rather than human decision making,
has made quality assurance of new treatment methods essential to
avoid treatment errors."
The complexity of real-time radiotherapy
has made quality assurance of new treatment methods essential to
avoid treatment errors.
That's why for the past three years his internationally renowned
team has been developing an innovative radiation semiconductor
detector system, known as the Dose Magnifying Glass (DMG), which
provides feedback to clinicians during and after test treatments to
help validate the patient treatment plan.
The DMG uses a novel silicon strip detector embedded in a
special plastic insertion, which allows for real-time mapping of
dosage in a phantom and improves spatial resolution, compared with
existing commercially available real-time quality assurance tools
from 5-10mm to 0.2mm.
"Silicon sensors offer reproducibility, due to well-developed
microelectronic technology and unbeatable spatial resolution, which
can't be achieved by other commercially available real-time
detectors," Professor Rozenfeld said.
"They also have the ability to include multichannel readout
electronics in a single chip."
Professor Rozenfeld said the benefits of the DMG can be seen in
the use of them for quality assurance in Stereotactic Radiosurgery
(SRS).
With this form of treatment, 'phantom studies' (using a dummy or
model to approximate the effect of radiation on human tissue) are
required for each patient prior to treatment to develop an
appropriate patient treatment plan.
The issue with current quality assurance practices for SRS is
that it is based on film dosimetry, which doesn't provide real-time
response and demands longer time for verification of treatment.
"DMG overcomes this issue by providing dose verification during
and immediately after plan delivery in a phantom model, which gives
real-time validation of the plan prior to patient treatment.
"In fact, comparison of film dosimetry and DMG has shown
agreement within 2 per cent for very complex SRS plans."
...an outstanding development, that will
make the treatment of cancer faster and more precise.
With these encouraging results, Professor Rozenfeld, with his
colleagues in Australia and overseas, is also testing DMG on other
new radiotherapy techniques.
"Feasibility studies of the first version of DMG in IMRT, SRS
and Tomotherapy were published in three recent publications of the
Medical Physics Journal as an outstanding development,
that will make the treatment of cancer faster and more precise.
"The fact is DMG technology and its modifications have opened
new horizons for quality assurance in contemporary radiation
therapy.
"New generations of these devices can be scaled up; making them
more suitable for many routine quality assurance applications in
IMRT and VMAT."
Professor Rozenfeld says he and his team are now looking at the
application of this technology for quality assurance on MRI LINAC,
which is a new challenge in itself.
"We are working in collaboration with Liverpool hospital where
the MRI LINAC is expected by the end of 2013," he said. "A new
generation of the DMG will be incorporated into quality assurance
of the next stage in radiation therapy."
| Dose Magnifying Glass (DMG) CMRP
research team and DMG featuring 128 channels DMG |
From the left to the right: Sam Khana(SG
CCC), A/Prof Martin Carolan (ICCC), Jeannie Wong, PhD
student, Prof Anatoly Rozenfeld, Dr Michael Lerch, Prof Peter
Metcalfe, and Dr Marco Petasecca (CMRP).
|
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