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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

A comparative analysis of the 3-field radiation treatment technique versus the 4-field radiation treatment technique in the treatment of patients presenting with either stage B or stage C prostate cancer

Moodley, Loganee January 2001 (has links)
Dissertation submitted in full compliance with the requirements for the Master's Degree in Technology: Radiography, Natal Technikon, 2001. / Radical radiotherapy is quite commonly used to treat localised prostate cancer. Acute and chronic toxicity to the bladder and rectum are dependant upon field arrangement, dose delivered to these organs and the volume of these organs that is within the target volume. A prospective study was conducted in order to determine whether the 3-field or the 4-field radiation treatment technique yields less severe bladder and rectal toxicity. METHODS AND MATERIALS Sixty patients with histologically confirmed stage B or C (Jewitt's staging system) prostate cancer, with or without radical prostatectomy were recruited from two private oncology institutions, 30 of whom were in group 1 (3-field technique) and 30 in group 2 (4-field technique). Pre-treatment and post-treatment prostatic specific antigen (PSA) levels were recorded in order to compare the effect of radiation on PSA. Both groups were treated in 2.00gy fractions per day to a dose of 60.00gy before the field arrangements were changed. This study therefore assessed the patients / M

Chromosomal radiosensitivity in South African breast cancer patients before and after radiotherapy

Muller, Xanthene 19 March 2013 (has links)
Introduction: Radiosensitivity (RS) of South African women with breast cancer was investigated as it has been studied in European women, but to date this has not been studied in South African women. The micronucleus assay was used to determine the amount of DNA damage on lymphocytes of breast cancer patients. Materials and Methods: The first component to this study involved the collection of blood samples from breast cancer patients and healthy individuals. For the second component, blood samples from breast cancer patients were collected before and after the completion of radiotherapy (RT). A centromeric micronucleus assay using the Fluorescent in situ Hybridisation (FISH) pancentromeric probe was used to investigate the origin of the micronuclei (MN) and to distinguish between radiation-induced [centromere negative (CM-)] and spontaneous [centromere positive (CM+)] MN. Results: Micronucleus frequencies were slightly higher in breast cancer patients than those observed in lymphocytes of healthy donors. This was noted for the different radiation doses and indicated a trend towards an enhanced chromosomal radiosensitivity in this cancer population. Results were compared before and after radiotherapy. The micronucleus scores for the 0 Gy (sham irradiated samples) were significantly higher (p < 0.05) post radiotherapy. This is an expected result as ionising radiation causes more damage. However, blood samples from post-therapy patients, were shown to have fewer MN after subsequent in vitro 2 Gy and 4 Gy irradiation respectively. When assessing the centromeric micronucleus assay results, a significantly (p < 0.05) higher number of CM- MN was observed than CM+ MN after RT, thereby indicating that ionising radiation causes more breaks in the chromosomes (clastogenic damage). Discussion and Conclusion: This study demonstrates that a group of South African breast cancer patients have slightly higher micronucleus frequencies compared to a population of healthy women, indicating a trend towards a higher sensitivity to radiation.

Potential prognostic factors for cervical cancer patients undergoing radiotherapy at Charlotte Maxeke Johannesburg Academic Hospital: a retrospective analysis

Pule, Maleshwane Lettie 11 September 2014 (has links)
Introduction: Although cervical cancer can be prevented through known interventions it still remains a major cause of mortality in developing countries. Currently in South Africa there is little literature on cervical cancer radiotherapy treatment and its prognostic factors. Knowledge of prognostic factors helps in understanding the determinants of a disease better and optimize treatment strategies. The aim of this study was to determine overall survival rate and to investigate potential prognostic factors for cervical cancer in patients who underwent radiotherapy during the period of 1 January 2004 to 31 December 2006 at the Division of Radiation Oncology, Charlotte Maxeke Johannesburg Academic Hospital. Methods: This was a retrospective cohort study of 900 patients who were treated with radiotherapy between 1 January 2004 and 31 December 2006. Patient and treatment related data was obtained from the hospital treatment records. Follow-up was then censored as of 31st of December 2008. Subjects of this study had either mono-therapy or a combination of therapies: external beam radiotherapy, brachytherapy and chemotherapy. A Cox regression model was fitted to determine the prognostic and predictive factors of cervical cancer. Kaplan Meier methods were used to establish the effect of different socio-demographic and clinic-pathological factors on overall survival. The overall two year survival was also determined. Results: At 2 years post-treatment for each individual patient, 26 out of 900 patients had died, 281 were still alive and 593 lost to follow up leaving 307 patients available for analysis. The overall 2 year mortality rate was 45 per 1000 person years and highest in the period of 0-6 months. In the final model, completion of brachytherapy remained a significant predictor of survival (HR=0.04, 95% CI: 0.01-0.11, p<0.001) after adjusting for all other factors. Furthermore, HIV status was the only significant prognostic factor (HR=3.23, 95% CI: 1.04- 10, p=0.042). Patients who had brachytherapy treatment prescribed and completed the prescription were 96% less likely to die compared to those who didn’t complete it at any point in time, after adjusting for age and HIV status. Patients who were HIV positive were approximately three times more likely to die as compared to HIV negative patients at any point in time after adjusting for age and completed brachytherapy. The overall 2-year survival rate was 92% for this group of patients. Conclusion: Completion of the brachytherapy prescription was a significant predictor of treatment outcome, while the patient’s HIV status was also a significant prognostic factor for treatment. Patients who were HIV positive were three-times more likely to die compared to HIV negative patients. The overall 2-year survival rate was 92%, however, these results need to be interpreted with caution due to the large loss to follow-up in this patient population. Prospective clinical trials are recommended in the future to confirm the validity of the findings of this work in a representative patient population. In addition this work puts forward some suggestions to optimize treatment of cervical cancer patients in typical university teaching public health centres in South Africa.

Nyongesa, Catherine 25 October 2006 (has links)
0300009Y Masters Dissertation (Faculty of Health Sciences) / A phase I dose escalation study of Cisplatin chemotherapy in patients with carcinoma of the cervix receiving pelvic radiotherapy PATIENTS WITH CARCINOMA OF THE CERVIX RECEIVING PELVIC RADIOTHERAPY.

Radiotherapy for the treatment of pain in malignant pleural mesothelioma

MacLeod, Nicholas James Lewis January 2016 (has links)
Aims: The primary aim of this thesis was to explore the role of palliative radiotherapy in the treatment of pain in malignant pleural mesothelioma (MPM). The effect of radiotherapy on other symptoms was also examined. Biomarkers which might predict response to radiotherapy (Quantitative Sensory Testing – QST) were explored and objective evidence of response was sought via interpretation of Computed Tomography (CT) scans. The thesis also examined the role of Positron Emission Tomography (PET)-CT in radiotherapy planning and characterising pain in MPM. Methods: A narrative review of the challenges of pain management in MPM and a systematic review of the evidence supporting the use of palliative radiotherapy for pain control in MPM, were undertaken. In addition, a multi-centre, single arm phase II trial was conducted which examined the role of radiotherapy in pain control in MPM. This trial also assessed the role of PET-CT in radiotherapy planning and allowed for a characterisation of MPM-related pain. These components form the basis of this thesis. Results: Palliative radiotherapy at a dose of 20 Gy in five daily fractions using 6 Megavoltage (MV) photons improves pain in a significant proportion of patients with MPM. It does not have a beneficial effect on other symptoms or on quality of life. QST does not appear to be a useful clinical biomarker indicating likelihood of response to radiotherapy. Objective evidence of response via CT is low. Incorporation of PET-CT in the radiotherapy planning process alters the anatomical location of the target volume in patients with MPM. There is also an association between the Standard Uptake Value (SUV) uptake and pain, with the areas with highest SUV uptake being associated with the areas of pain. PET-CT results in upstaging of a significant proportion of patients. Pain is often severe and debilitating for patients with MPM and it has often a combination of neuropathic and nociceptive mechanisms. The presence of a neuropathic component to the pain is not associated with an increased likelihood of response to radiotherapy. Conclusions: Radiotherapy is effective at relieving pain in a proportion of patients with MPM and should be considered for all patients with MPM-related pain. PET-CT improves multiple parameters in the radiotherapy planning process compared with CT alone. QST parameters have not been shown to predict those patients who are likely to respond to radiotherapy.

Physical aspects of selective internal radiation therapy for hepatic cancer.

January 1996 (has links)
by Ho King Wah Stephen. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 251-304). / Title Page --- p.1 / Table of Contents --- p.2 / Summary --- p.3 / Glossary of abbreviations used in the thesis --- p.10 / List of Figures --- p.12 / List of Tables --- p.20 / Acknowledgments --- p.24 / Chapter Chapter 1 --- Hepatic Cancer - Review of the Medical Literature --- p.25 / Chapter Chapter 2 --- Selective Internal Radiation Therapy - Review of the Medical Literature --- p.47 / Chapter Chapter 3 --- The Background In Physics --- p.76 / Chapter Chapter 4 --- Hypothesis and Testing the Hypothesis --- p.88 / Chapter Chapter 5 --- Parameters Required in the Partition Model --- p.98 / Chapter Chapter 6 --- Prediction of Radiation Dose and Verification of the Partition Model --- p.143 / Chapter Chapter 7 --- Clinical Evaluation of the Partition Model --- p.181 / Chapter Chapter 8 --- Conclusions and Future Development --- p.248 / References --- p.251

Physical and biological parameters affecting the reaction of human tissues and tumours to ionizing radiation: a statistical and experimental study of the development of methods for determining therapeutic ratios, optimal dosage factors, and a theoretical prognosis in clinical radiation therapy

09 February 2015 (has links)
No description available.

A novel deformable phantom for 4D radiotherapy verification /

Margeanu, Monica. January 2007 (has links)
No description available.

Radiotherapy for bone metastases and neuropathic bone pain

Roos, D. E. January 2005 (has links)
I have a background of active research in Radiation Oncology since passing the final examination of the Royal Australian and New Zealand College of Radiologists ( RANZCR ) at the first attempt in 1992. My first two papers were published the following year [ 1,2 - see curriculum vitae ], and there are currently 49 publications ( 26 first authorships ). My primary research interest has involved the use of radiotherapy ( RT ) for palliation of painful bone metastases. This interest originated from a year at Mt Vernon Hospital, UK, as the inaugural RANZCR Windeyer Fellow in Clinical Oncology ( 1993 ). I worked with Dr Peter Hoskin, a leading figure in the British Bone Pain Trial Working Party responsible for three randomised fractionation trials on this subject. These and many other previous and subsequent studies have demonstrated ( counter - intuitively ) that low dose single fraction RT is as effective as higher dose fractionated schedules in relieving bone pain, with intention - to - treat overall response rates ( RRs ) of about 60 %. However, the studies provided virtually no data on the efficacy of RT specifically for bone pain with a neuropathic component ( NBP ), a scenario occurring in perhaps as many as 20 % of patients with bone metastases during the course of their disease. On returning to Australia as a consultant radiation oncologist at the Royal Adelaide Hospital in 1994, I joined the Trans - Tasman Radiation Oncology Group ( TROG ), the major radiotherapy clinical trials group in Australasia. During the following year, I developed a protocol for a randomised controlled trial comparing one with five fractions of RT for NBP ( TROG 96.05 ). The first patient was registered in February 1996, and a total of 15 centres in Australia ( 11 ), New Zealand ( 3 ) and UK ( 1 ) took part. A National Health and Medical Research Council Project Grant of $ 172,000 was awarded for the study ( 1998-2000 ). Preliminary findings ( blinded to trial arm ) were published in 2000 [ 23 ], and extensive quality assurance activities for the trial were summarised in two further publications [ 21,38 ]. The accrual target was met in December 2002 ( n = 272 ) and the final analysis was reported as an oral presentation at the 12th European Cancer Congress, Copenhagen, September 2003. The essential findings were that NBP responds similarly to localised pain ( overall intention - to - treat RR 57 % ) with no statistically significant difference in RR or time to treatment failure between randomisation arms [ 43 ]. A subsequent cost analysis quantified the relative cost to the Australian healthcare system for the two fractionation schedules [ 47 ]. During the conduct of the trial, I undertook and published a survey confirming the reluctance of Australasian radiation oncologists to use single fractions for painful bone metastases despite the emerging randomised trial results [ 24 ]. I also contributed to the international debate on this controversial subject as co - author with three high profile researchers in a Letter - to - the - Editor [ 20 ], and was a member of an International Consensus Panel on palliative radiotherapy endpoints for future bone metastases trials [ Chow E et al. Radiother Oncol 2002 ; 64 : 275 - 80 ]. I presented invited lectures entitled : Fractionation regimens for metastatic bone pain ( RANZCR Scientific Meeting, Brisbane, 1998 ) ; Neuropathic pain and bone metastases ( Royal College of Radiologists Second Consensus Workshop in Palliative Radiotherapy and Symptom Control, London, 2000 ) [ 27 ] ; Radiotherapy for neuropathic bone pain : TROG 96.05 update ( International Congress of Radiation Oncology, Melbourne, 2001 ) [ 30 ]. My recognised expertise in this field also led to invitations to write an Editorial on the published overviews of bone pain studies [ 40 ], and a book chapter on bone metastases from lung cancer [ 49 ]. My active role in bone pain research continues. The abovementioned International Consensus Panel collaboration led to the development of the first randomised trial on re - treatment of bone metastases with RT. This National Cancer Institute of Canada sponsored international Intergroup trial ( NCIC SC.20 / TROG 03.08 ) has an accrual target of 650 patients and was activated in January 2004. I am the Australasian Co - Chair, securing $ 40,000 funding for local capitation from Cancer Council Australia in February 2004. I believe this body of work constitutes a significant contribution to the literature on RT for bone metastases, and NBP in particular. My research on the latter constitutes the first prospective data ever obtained on RT for this clinical problem, enabling informed selection of single or multiple fraction treatment schedules. / Thesis (M.D.)--Department of Medicine, 2005.

Optimization of Dose Schedules in Radiotherapy

Miasnikof, Pierre 18 March 2013 (has links)
Purpose: Fractionation in radiotherapy is the scheduled break up of a total treatment dose into individual doses. The goal of this thesis is to seek a mathematically optimal dose schedule, in the context of a biological tissue dose-response model, the linear-quadratic function. Methods: We examined the mathematical properties of the fractionation problem in the context of an arbitrary number of sensitive-structure constraints and determined the properties of the optima. We also implemented a numerical search technique to solve the problem. Results: On the theoretical side, we confirmed and extended the results in the literature. We showed the optima always occur at the intersection of two or more constraints or at the equal dose per fraction point (or at any arbitrary feasible point on the boundary, which includes the two points just mentioned). On the numerical side, we successfully implemented a simulated annealing algorithm to our problem.

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