The Use Of Electronic Portal Imaging Devices For The Dosimetric Verification Of Complex Radiotherapy Treatments
Funder
National Health and Medical Research Council
Funding Amount
$260,949.00
Summary
The prognosis for someone diagnosed with cancer is much better than commonly believed. If detected early, malignant tumours are generally well localised. During these early stages of tumour growth high doses of radiation therapy can with a high probability, eradicate a cancer but come with the cost of causing unacceptable damage to normal tissue. A specific goal of improving the technology of radiation therapy is to reduce the probability of damage to normal tissue. Achieving this goal may allow ....The prognosis for someone diagnosed with cancer is much better than commonly believed. If detected early, malignant tumours are generally well localised. During these early stages of tumour growth high doses of radiation therapy can with a high probability, eradicate a cancer but come with the cost of causing unacceptable damage to normal tissue. A specific goal of improving the technology of radiation therapy is to reduce the probability of damage to normal tissue. Achieving this goal may allow delivery of higher doses with an associated increase in the chance of controlling the tumour. One of the challenges in radiation therapy is that tumours do not come in shapes that are easy to treat. Tumours extend into cavities and push aside healthy organs growing into complex 3D shapes. The careful shaping of the radiation beams to deliver dose distributions that match the 3D shape of the target is known as 3D conformal radiotherapy (3DCRT). Intensity Modulated Radiotherapy (IMRT) is an advanced form of 3DCRT that allows the delivered dose to be closely tailored to the shape of complex tumour volumes while sparing neighbouring healthy tissues. One of the consequences of increasing the conformality of radiation therapy is an increased sensitivity to errors in the preparation and execution of the treatment. If the maximum gain in the treatment outcome using 3DCRT and IMRT techniques is to be achieved then it is crucial that the correct volume is treated to the correct dose on each day of the treatment. This requires new improved methods and techniques for verifying the daily delivery of the treatment. In this project we aim to develop the use of online digital imaging devices for measuring the delivered dose during treatment. This will increase the confidence with which these new conformal radiotherapy techniques can be delivered allowing their true potential for improving patient treatment outcomes to be realised.Read moreRead less
The Effects Of Inherent Inaccuracies In DXA In Vivo BMD Measurements On Osteopenic/Osteoporotic Diagnostics/Prognositics
Funder
National Health and Medical Research Council
Funding Amount
$411,980.00
Summary
Osteoporosis (porous bone) and consequent associated bone fractures of mainly post-menopausal women and the elderly of both genders constitutes a significant, widespread and rapidly growing public health problem. It is already a major health-cost burden in Australia and worldwide and is set to increase dramatically over the next few decades as the proportion of the population at or above the osteoporosis-prone age increases sharply. Current diagnostic evaluations of osteoporosis, bone mineral st ....Osteoporosis (porous bone) and consequent associated bone fractures of mainly post-menopausal women and the elderly of both genders constitutes a significant, widespread and rapidly growing public health problem. It is already a major health-cost burden in Australia and worldwide and is set to increase dramatically over the next few decades as the proportion of the population at or above the osteoporosis-prone age increases sharply. Current diagnostic evaluations of osteoporosis, bone mineral status of the skeleton, mechanical integrity of bone, and bone fracture risk are mainly based on X-ray absorption measurements of a given individual's bone mineral density (BMD) using Dual-energy X-ray Absorptiometric (DXA) bone densitometer instrumentation. New drugs to retard, ameliorate, or reverse the low bone mineral density condition of osteoporosis are now becoming available, but cannot be prescribed unless sufficiently low BMD is demonstrated for a given patient. The efficacy of these drugs is usually held to be greatest at the earliest stage of osteoporosis (osteopenia) and their effectiveness evaluated on the basis of DXA-measured bone mineral density. The Chief Investigator of this project has already shown by published quantitative analysis and simulation studies that such BMD measurements are inherently inaccurate; that errors of 20% and greater can readily pertain, particularly for those patients at the early stages of osteoporosis and those at or above the osteoporosis-prone age -- the very individuals for whom bone mineral density values are often of paramount interest and concern. These systematic DXA inaccuracies can be large enough to either mask the presence of osteoporosis or lead to false diagnoses and patient monitoring results. The present project, for the first time anywhere, is desiged to quantitatively establish the extent of these inaccuracies using actual DXA densitometers utilizing sophisitcated and precise methods.Read moreRead less