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Development Of A Multi-Detector Quality Assurance Instrument For Intensity Modulated Radiotherapy, Claudiu Sebastian Porumb

University of Wollongong Thesis Collection 1954-2016

The advancement of delivery techniques in external beam radiotherapy and ever-increasing complexity of delivery modalities requires that quality assurance systems keep pace with smaller radiation fields, larger dose gradients and dynamic dose profiles. This work describes the development of a novel pre-treatment and in-vivo quality assurance devices for use in external beam radiotherapy, including small-beam stereotactic radiotherapy.

Dosimetry In Synchrotron Microbeam Radiation Therapy, Pauline Fournier

University of Wollongong Thesis Collection 1954-2016

Microbeam Radiation Therapy (MRT) is a novel radiation therapy modality currently developed at several synchrotron sources around the world. The MRT technique is based on the use of plane parallel arrays of microbeams produced by a multislit collimator (MSC). The major benefit of MRT lies in the dose volume effect: a higher radiation tolerance of the normal tissue when using micrometer scale beam size. Moreover, pre-clinical studies highlighted the detrimental effect of MRT on the tumor tissue and demonstrated the presence of a differential effect between normal and tumor tissue. One of the possible application of MRT is the treatment …

Data Acquisition Systems Design For Quality Assurance In Advanced Radiation Dosimetry, Iolanda Fuduli

University of Wollongong Thesis Collection 1954-2016

During the past years, radiotherapy has become a widely used technique for treatment of tumors on different areas of the human body. The evolution of the technology has led to the necessity to assure the safety of the patient at any time during any kind of treatment. A wide range of instrumentation has been developed to perform a state of art dosimetry for the Quality Assurance (QA) of the irradiating beam. Tumors can be treated using different methodologies, depending on their position and dimension. The radiation techniques have been classified in three major groups: Microbeam Radiation Therapy (MRT), Brachytherapy and …

Dose Verification For Ophthalmic Plaque Brachytherapy Quality Assurance, Michael R. Weaver

University of Wollongong Thesis Collection 1954-2016

Intraocular melanoma is a rare form of cancer with a high mortality rate and limited effective treatment options. It causes death in 45% of patients within 15 years, typically within 6 - 9 months of the first signs of metastatic spread. Plaque brachytherapy is one of the most common treatments, and has proven to be quite successful at local tumour control. It involves temporarily stitching a small, radionuclide-bearing device, called an eye plaque, on the surface of the eye above the tumour.

The accuracy of treatment planning and dose verification procedures remains suboptimal, due to the very high gradient of …

Radiation-Induced Cancer Risk Derived From Dosimetry Of Image Guided Breast Radiation Therapy, Alexandra Quinn

University of Wollongong Thesis Collection 1954-2016

Image guidance is an integral component of modern radiation therapy, enabling the visualisation and verification of the tumour volume and organ motion prior to and during treatment delivery. This thesis represents a body of work examining the additional radiation dose and associated risk of image guidance during breast radiation therapy.

There are three main areas within the thesis. The first was the dosimetric assessment of breast radiation therapy treatment techniques and associated imaging. Radiation dose was measured within an anthropomorphic phantom with thermoluminescent dosimeters and metal-­‐oxide-­‐semiconductor-­‐field effect-­‐transistor dosimeters (skin only). Tissue dose values were obtained from the average of dosimetric …

An Investigation Into The Use Of The Moskin Detector For Beam Profile And Output Measurements In Stereotactic And Small Field Dosimetry, Dalia Hadaya

University of Wollongong Thesis Collection 1954-2016

Stereotactic radiation therapy or radiosurgery involves the delivery of a radiation dose, using small radiation beams to treat tumours or lesions, typically within the brain. To derive accurate beam models for stereotactic treatment planning, high spatial and dosimetric accuracy is required. The stereotactic beams are required to be characterised with regards to dosimetry. The MOSkin detector developed by the Centre of Medical Physics at the University of Wollongong was investigated to determine if it could be used for dose characterisation of stereotactic small field radiation beams.

The MOSkin was compared to the IBA Stereotactic field diode (SFD), a PTW 31014 …

Characterisation Of Bulk Silicon Diodes For The Magic Plate 512 Dosimeter Array, Daniel Robinson

University of Wollongong Thesis Collection 1954-2016

The aim of this study is the characterisation of an innovative silicon 2D array Detector named Magic Plate 512 for dosimetry in four-dimensional small field external beam radiotherapy. The need for such a device arises from the inability of current commercial dosimetric devices to account for thoracic movement during 4- dimensional radiation therapy (4DRT). 4DRT represents the next step from intensity modulated radiation therapy (IMRT), where organ movements during treatment are no longer neglected as the treatment beam will actively follow a target volume. Dynamic multi-leaf collimators (DMLCs) are one solution to this issue of patient respiration as a DMLC …

Optimising The Packaging Of Semiconductor Detectors To Improve Their Energy Response To Gamma And Neutron Radiation For Radiation Protection: A Geant4 Monte Carlo Study, Mohd Amir Radhi Othman

University of Wollongong Thesis Collection 1954-2016

There are many types of semiconductor detectors used in radiation detection and dosimetry. A common problem of these detectors under a wide energy spectrum is that their response in a radiation field depends on energy. In radiation protection-applications, gamma and neutron are the most common primary radiation. Other forms of radiation, such as hadronic particles, are important in space applications, but are not included in the scope of this study because they deserve a separate examination. This study mainly focuses on the development of semiconductor dosimeters for mixed gamma-neutron, with an improved energy response achieved by an innovative design and …

Output Factors For Small Field Megavoltage Photon Beams, Kirbie Jaye Warrener

University of Wollongong Thesis Collection 1954-2016

Treatment planning systems and beam modelling are built upon and validated by experimentally measured parameters, both in water and in air. Accurate dose measurements are challenging in small radiation fields because there is no commercially available real-time dosimeter that can accurately measure output factors without the use of specific small field correction factors.

This study supplements the measurements made with a range of commercially available dosimeters with those made using a waterequivalent fibre optic dosimeter (FOD), validated with radiochromic film. The results for in-water output factors, Sc,p , and in-air output factors, Sc , were measured for field sizes down …

Mosfet Annealing And Interface Dosimetry In Contemporary Radiation Therapy, Sami Mohammedsaleh Alshaikh

University of Wollongong Thesis Collection 1954-2016

[Background and Purpose] In-vivo, skin, and interface dosimetry in modern radiation therapy is an important issue that demands a reliable radiation dosimeter capable of measuring skin doses. The Metal Oxide Semiconductor Field Effect Transistor “MOSFET” dosimeter became popular as a radiation dosimeter in radiation therapy and one of its recently designed versions for skin dosimetry, called MOSkin, has become very popular. Unfortunately MOSFET has a limited lifespan due to a saturated build up of positive charges in its sensitive dosimetric volume - gate oxide, which is mainly located near the Silicon- Silicon dioxide (Si-SiO₂) interface. …

Gafchromic® Ebt2 Film Dosimetry In An Anthropomorphic Head And Neck Phantom Measuring Intensity Modulated Radiation Therapy (Imrt) Dose Distributions, Megan Horsfield

University of Wollongong Thesis Collection 1954-2016

Cancer is one of the leading causes of death in Australia. Radiation therapy is one of the main options for the treatment of cancer. Intensity modulated radiation therapy (IMRT) is a new implementation of existing radiation therapy techniques which spares critical structures e.g. parotid glands.

The checking of the accuracy of IMRT treatment delivery is important as any errors may result in further complications for the patient. Hence a level III dosimetry survey of departments in Australia is currently underway. This is called the ICARIS (a dosimetric Inter- Comparison of Australian Radiotherapy Systems) project.

This thesis describes precursor equipment testing …

Development Of Data Acquisition System For Multi Channel Dosimetry In The Quality Assurance Of Microbeam Radiation Therapy, Sutinder Kumar Khanna

University of Wollongong Thesis Collection 1954-2016

In this research project a DAQ (Data Acquisition) system was developed for use with a new 128 channel, silicon strip detector (SSD) which was designed at the Centre for Medical Radiation Physics (CMRP) University of Wollongong. Software for the data acquisition has been developed using the graphical programming language LabVIEW to readout and display, in real-time, the calibrated and normalised detector response of all 128 channels. In addition to this, was the development of software features, and related hardware that initiate a treatment beam dump should the measured instantaneous dose rate go above a predetermined threshold in any of the …