Radiotherapy treatments need adequate quality control (QC) to ensure a correct delivery of the prescribed dose to the target area. One of the most extended safety nets for treatments in... Show moreRadiotherapy treatments need adequate quality control (QC) to ensure a correct delivery of the prescribed dose to the target area. One of the most extended safety nets for treatments in conventional radiotherapy machines is in-vivo EPID dosimetry, which uses the dose acquired by an Electronic Portal Imaging Device (EPID) during treatment to accurately reconstruct the dose as it was delivered to the patient.We developed a method to validate radiotherapy treatments delivered on a novel system: the Unity MR-Linac. This machine, which combines a radiation source (linac) and an imaging device (MRI), will help to irradiate tumors more accurately by means of a new range of techniques only available thanks to the image guidance of the MRI during irradiation. The verification of such treatments can be performed by using images of the delivered beam captured by an EPID situated opposite to the radiation source, behind the cryostat of the MRI scanner. This project focuses on the adaptation of an already existing algorithm used with conventional linacs to the new physics and design characteristics of the Unity MR-linac. The main challenge for this adaptation is the presence of the MRI scanner between the patient and the EPID, acting as a secondary source of scatter and as an attenuation medium for the beam. Show less
Colorectal cancer is one of the most common cancers worldwide. Although there have been several improvements in screening, staging, and treatment in the past decades, survival differences remain.... Show moreColorectal cancer is one of the most common cancers worldwide. Although there have been several improvements in screening, staging, and treatment in the past decades, survival differences remain. For example among certain subgroups of patients, such as elderly patients and patients with comorbidities. Besides, inequalities in the quality of care between European countries remain. Quality control on surgery, radiotherapy, and pathology have been introduced in trials, followed by incorporation in the general care. Another option to incorporate improved quality of care is via an audit structure in which hospitals and clinicians can improve their results by learning from their own outcome statistics and those from colleagues treating a similar patient group. Although all these audit structures have achieved excellent results within countries, differences in outcome between European countries remain. A next step will b e to combine these national audits. The combined audit structure will provide a network in which __best practices__ can be compared and identified, including for certain subgroups, which has been initiated as European Registration of Cancer Care (EURECCA). To achieve optimal care for all patients, multidisciplinary care is the only way. By comparing multidisciplinary audit structures across countries, optimal treatment strategies within subgroups can be identified Show less
This thesis focuses on quality assurance of rectal cancer treatment, in particular of the surgical treatment. Both oncological short-term and long-term outcome parameters are studied, but also... Show moreThis thesis focuses on quality assurance of rectal cancer treatment, in particular of the surgical treatment. Both oncological short-term and long-term outcome parameters are studied, but also other end-points which are important for quality assurance are investigated, such as anastomotic leakage and stoma reversal. The introduction of total mesorectal excision (TME) surgery resulted in an improved survival of patients with rectal cancer. However, survival of the elderly patients and patients treated with an abdominoperineal resection improved less. For frail elderly patients, postoperative mortality is an important competitive risk factor and other treatment schedules might be more appropriate. The abdominoperineal resection itself was associated with a nonradical resection, decreased local control and decreased survival compared to patients treated with a low anterior resection. To improve these results, in selected cases preoperative treatment should consist of chemoradiotherapy and/or a widened resection. Anastomotic leakage is a feared complication after colorectal surgery. After surviving this complication, the overall survival rate in the long-term is still reduced. However, oncological outcome was not significantly affected. The presence of a stoma resulted in a lower symptomatic leakage rate. 20% of stomas was never reversed. Standardised postoperative surveillance resulted in an earlier confirmation of the diagnosis anastomotic leakage. Show less
