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Intensity modulated radiotherapy (IMRT) can potentially increase the dose delivered to liver tumours while sparing normal tissues from dose. More complex IMRT, with more modulation of the radiation beam is more susceptible to geometric and dosimetric uncertainties than simpler radiotherapy plans. Simple breath-hold liver IMRT using few radiation beam segments (<30) was investigated in 27 patients to determine the quality of treatment in terms of tumour dose coverage and normal tissue sparing as compared to index IMRT using >30 segments. In all 27 plans number of segments was reduced to <30 without compromising tumour coverage or normal tissue dose constraints, at the expense of dose conformity. Delivered tumour and normal tissue dose did not differ statistically between IMRT plans when accounting for treatment residual geometric error. This research supports considering the use of simple IMRT for treatment of liver cancer, except when loss of dose conformation is undesirable (i.e. very high doses).

For over a century, physicians have prescribed x-ray radiation to destroy or impede the growth of cancerous tumours. Modern radiation therapy machines shape the radiation beam to balance the competing goals of maximizing irradiation of cancerous tissue and minimizing irradiation of healthy tissue, an objective complicated by tumour motion during the treatment and errors positioning the patient to align the tumour with the radiation beam. Recent medical imaging advances have motivated interest in using feedback during radiation therapy to track the tumour in real time and mitigate these complications. This thesis investigates how real-time feedback control can be used to track the tumour and focus the radiation beam tightly around the tumour. Improving on these results, a feedback control system is proposed for intensity modulated radiation therapy which allows a non-uniform radiation dose to be applied to the tumour. Motivated by the results of the proposed control systems, this thesis also examines two theoretical control problems: estimating the output of an unknown system when a sensor delay prevents its direct measurement, and designing a controller to provide an arbitrarily fast nonovershooting step response.

In radiation treatment, a sufficiently high radiation dose must be delivered to the tissue volumes containing the tumor cells while the lowest possible dose should be deposited in surrounding healthy tissue. We developed an original approach that is fast and easy to implement for the early assessment of the efficiency of radiation sensitizers and protectors. In addition, we characterized a new femtosecond laser pulse irradiation technique. We are able to deposit a considerable dose with a very high dose rate inside a well-controlled macroscopic volume without deposition of energy in front or behind the target volume. The radioprotective efficiency was measured by irradiation of the Fricke solution incorporating a compound under study and measuring the corresponding production of ferric ions G (Fe3+ ). The production of ferric ions is most sensitive to the radical species produced in the radiolysis of water. We studied experimentally and simulated with a full Monte-Carlo computer code the radiation-induced chemistry of Fricke/cystamine solutions. Results clearly indicate that the protective effect of cystamine originates from its radical-capturing ability, which allows this compound to compete with the ferrous ions for the various fre radicals - especially · OH radicals and H· atoms - formed during irradiation of the surrounding water. The sensitizing capacity of radiation sensitizers was measured by irradiation of a polyacrylamide gel (PAG) dosimeter incorporating a compound under study and measuring the corresponding increase in the gradient between spin-spin relaxation rate (R2 ) and absorbed dose. We measured an irradiation energy-dependent increase in R 2 -dose sensitivity for halogenated compounds or a decrease for radioprotectors. Finally, we studied a novel laser irradiation method called "filamentation". We showed that this phenomenon results in an unprecedented deposition of energy and the dose rate thus achieved exceeds by orders of magnitude values previously reported for the most intense clinical radiotherapy systems. Moreover, the length of the dose-fre entrance region was adjusted by selecting the duration of femtosecond laser pulses. In addition, we provided evidence that the biological damage caused by this irradiation was similar to other ionizing radiation sources. [symboles non conformes]

M.Tech. / In spite of the improvement in the delivery of anti-cancer treatments over the past decade, side effects from these treatments remain inevitable. A common, distressing side effect that all cancer patients experience is fatigue. However, cancer related fatigue (CRF) remains one that is under-reported and under-treated. CRF is a topic that has received very limited attention in the South African context. Regardless of the amount of literature available on CRF, many questions continue to go unanswered. CRF has been identified as a side effect that is associated with physical, mental and psychological elements. Consequently, it has the ability to cause a delay in treatment schedules, impinge on daily functioning and impact negatively on the quality of life (QoL) in the cancer patient. Effective management strategies for patients during and after radiation treatment are thus essential to improve QoL. The aim of the study was to investigate the general pattern of fatigue experienced by patients diagnosed with various types of cancers during a radical course of radiotherapy. For the purpose of this study fatigue was defined according to the National Comprehensive Cancer Network (NCCN) Practice Guidelines in Oncology (www.nccn.org): “a distressing persistent subjective sense of tiredness or exhaustion related to cancer or cancer treatment that is not proportional to recent activity and interferes with usual functioning” A cross-sectional, theory-generating study was conducted to explore and describe the prevalence of fatigue, factors that could influence fatigue scores, strategies being used to alleviate this side effect and the impact of fatigue on QoL. One hundred and eighty patients were asked to complete a self-developed questionnaire in three oncology centres in Gauteng, South Africa. The NCCN Clinical Practice Guidelines in Oncology were used as a framework to direct the study. The results of the study illustrate that fatigue scores increased as radiotherapy progressed. However, not all the variables explored in the study significantly impacted on fatigue scores. The study revealed, though, that all cancer patients do experience CRF irrespective of the diagnosis. Management of the causes of CRF is thus essential to improve QoL for cancer patients.

D. Litt et Phil. / It is well known that high levels of anxiety and/or depression often accompany the diagnosis and treatment of cancer. Literature from various sources, but in particular from the fairly new field of research, Psychoneuroimmunology, also provides ample evidence that excessive anxiety and/or depression can be immunosuppressive. It makes sense, therefore, that any intervention restoring balance to the immuno-regulatory system, thereby allowing the body’s innate healing processes to focus on eliminating cancer, is highly desirable. In line with current thinking based on the mind-body connection as well as cognitive behavioural techniques utilised in many therapeutic settings, various psychological interventions have been found to help the patient gain a better sense of control over distressing symptoms and side-effects of cancer. Some of these include: basic cognitive restructuring, hypnotherapy, relaxation-meditation techniques, art and music therapy, and guided imagery. Substantial international research illustrates the beneficial effect that relaxation and/or guided imagery provides in such diverse settings including work, sport and health. In this regard, it was decided to run a pilot study to ascertain whether a customised tape recording with a relaxation and guided imagery dialogue aimed at helping patients manage and cope with negative symptoms of cancer, could significantly reduce anxiety levels in patients with cancer receiving radiotherapy. To operationalise the above, 30 men and women, aged between 20 and 80, with Stages 1, 2 or 3 breast, prostrate, gynaecological cancers, and head and neck cancers, who were about to commence radical (minimum 25 fractions) radiotherapy, were randomly selected to an experimental and a control group. A consecutive sample, pre-test post-test experimental design was applied to this study in which the experimental and control groups were subjected to pre- and post radiotherapy Hospital Anxiety & Depression (HAD) Scale, Institute for Personality Assessment and Training (IPAT) Anxiety Scale and blood pressure measurements during their 1st, 3rd, 6th week cycle of treatments, as well as a final measurement 12 weeks after commencement of therapy. The main hypothesis of this pilot study was that there would be statistically significant decreases in levels of anxiety as a result of the intervention of guided imagery tape recording in patients with non-metastatic cancer undergoing curative radiotherapy. For the intervention, each experimental participant was taught a relaxation technique and then following an interview a customised guided imagery dialogue developed for the participant’s sole use. The participant was requested to listen to this tape at least once a day. The control group had the same pre- and post tests as the experimental group, but did not receive any intervention. Statistical analysis of the data revealed that the experimental group showed a tendency towards decreased blood pressure and anxiety over the course of radiotherapy. The most significant change, however, was noted in terms of diastolic blood pressure, suggesting that the intervention corresponded to a physiological decrease in anxiety. There was not a statistically significant difference in terms of the measured psychological variables. A general conclusion to this pilot study suggests that whilst guided imagery may contribute to a lowering of anxiety, additional cognitive intervention would probably affect a more substantial and sustained change in the patient. Although this pilot study revealed some methodological weaknesses the results are sufficiently encouraging to warrant further in-depth research regarding the use of guided imagery as a cost-effective, easy method for individuals to learn and utilise as part of their integrative cancer treatment programme.

Student Number : 0003555T - MSc (Eng) dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / Successful radiotherapy treatments with high-energy proton beams require the accurate positioning of patients. This paper investigates computational methods for achieving accurate treatment setups in proton therapy based on the geometrical differences between a double exposed portal radiograph (PR) and a reference image obtained from the treatment planning process. The first step in these methods involves aligning the boundary of the radiation field in the PR with a reference boundary defined by the treatment plan. We propose using the generalised Hough transform (GHT), followed by an optimisation routine to align the field boundaries. It is found that this method worked successfully on ten tested examples, and aligns up to 82% of reference boundary points onto the field boundary. The next step requires quantising the patients anatomical shifts relative to the field boundary. Using simulated images, a number of intensity-based similarity measures and optimisation routines are tested on a 3D/2D registration. It is found that the simulated annealing algorithm minimising the correlation coefficient provided the most accurate solution in the least number of function evaluations.

M.Med., Faculty of Health Sciences, University of the Witwatersrand, 2009 / Objectives Cancer of the cervix is one of the commonest cancers in South African females. Up to 30% of patients are HIV positive. The addition of chemotherapy to radiotherapy has been shown to significantly improve local control and survival and concurrent chemoradiation is the standard treatment for locally advanced cancer of the cervix. There is very limited literature available concerning the tolerance and efficacy of this treatment in HIV positive patients. This study aims to assess the acute toxicity of combined modality treatment in these patients. This study is part of a multicenter International Atomic Energy Agency sponsored study. Materials and methods Patients with FIGO stage IB2 to IIIB (without hydronephrosis) cervical cancer and who are HIV positive, were randomized to receive radiotherapy alone or chemo-radiation. All patients received 46 Gy in 23 fractions external beam radiation and high-dose-ratei brachytherapy 8 Gy x 3 fractions. Chemotherapy consisted of bolus Cisplatin 30mg/m2 weekly given concurrently with the radiotherapy. Acute treatment toxicity was documented weekly during treatment. Results 64 patients were recruited to the study. 31 patients were randomized to the chemoradiation arm and 33 patients to the radiation alone arm. Of the 64 patients recruited to the study, 6 in the chemoradiation arm and 5 in the radiation only arm did not receive any treatment and were therefore not evaluated. Stage IIB was the most common stage. The mean CD4 count was 410 in the chemoradiation arm vs. 358.4 in the radiation only arm at randomization. Only 6 patients were on antiretroviral therapy at start of treatment, 3 in each arm. The number of chemotherapy cycles received by patients in the chemoradiation arm ranged between 0 and 5 cycles. A total of 96 chemotherapy cycles were administered, with a median of 4 cycles per patient. Overall, at least 76% of patients received at least 4 cycles of chemotherapy. The full five intended courses of cisplatin were administered in 10 (40%) patients. Chemotherapy was not administered most commonly due to toxicity (renal, leucopaenia), other reasons being logistical and non compliance. The principle major adverse effects observed were leucopaenia and cutaneous reactions.