MSc in Radiotherapy
Permanent URI for this collectionhttps://eresearch.qmu.ac.uk/handle/20.500.12289/7217
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Item A systematic Review: Comparing the Effectiveness of Internal and External Markers as Surrogates for Tracking Tumour Motion in Patients Undergoing Stereotactic Ablative Body Radiotherapy for Non Small Cell Lung Cancer(Queen Margaret University, 2016)Aim: The aim of this study is to evaluate if internal or external markers are effective at tracking the tumour when treating NSCLC patients with SABR. Background: Stereotactic ablative radiotherapy (SABR) has improved the survival for medically inoperable patients with non-small cell lung cancer (NSCLC). Respiratory tumour motion is challenging when implementing SABR treatment. This tumour motion can be localised and tracked by either internal or external markers. Method: A systematic review was conducted following PRISMA guidelines, to assess the treatment of NSCLC with SABR utilising either internal or external surrogates to determine which is more efficient at tracking tumour motion. The secondary endpoint was analysing if either surrogate demonstrated less toxicities and an improved rate of local control and overall survival outcomes. Eligible studies of SABR using surrogates to localise the tumour were retrieved through extensive searches of the Medline, CINAHL Plus, PubMed, Cochrane Library and Science Direct databases from 2008 to May 2016. Result: The search returned 120 articles; 17 met the inclusion criteria. No one paper had the ability to answer both primary and secondary outcomes. Four articles were included for analysis of the primary outcomes and 13 articles for secondary outcomes. From these articles data was extracted and analysed. Conclusion: The primary conclusion from the systematic review suggests internal markers are more effective at tumour tracking. The correlation between tumour and external marker did not demonstrate accurate results. Furthermore, due to technological advances, radiotherapy systems are incorporating both surrogates to track the tumour, hence the reason only a select few papers are included in the primary outcomes. Toxicity outcomes show that external markers are more beneficial as they incur less side effects. In contrast, local control and overall survival have better outcomes when using internal markers.Item A Comparison of Two Imaging Protocols for Patient's Receiving a Radical Course of Radiotherapy to the Brain.(Queen Margaret University, 2016)Background Accurate patient positioning is vital in radiotherapy to deliver precise targets to defined areas. Image guided radiotherapy (IGRT) can help to increase this accuracy. In a large regional radiotherapy department patients receiving a course of radical radiotherapy to the brain undergo daily image guidance prior to delivery of treatment. A 3-mm tolerance of movement is in place for these patients. This service evaluation examined whether it is essential to perform this type of imaging on a daily basis or whether a less frequent imaging protocol would be more clinically relevant. Method This retrospective small scale service evaluation was based on quantitative research. A quasi-experimental design was used. IGRT data was collected from 25 patients who had previously undergone daily image radiotherapy to the brain. Retrospectively couch movements in anterior/posterior, left /right and superior/inferior directions for all the patients for a total of 704 fractions. Data was divided into two groups. Group 1 (daily image group), this group consisted of data from all 25 patients for each daily image recorded throughout their treatment. Group 2 (weekly image group) consisted of data from all patients on the first three days then once weekly. Results A one-sided one-sample t-test was performed to confirm that the mean movement was less than 3-mm. The p-value was p=0.000, the null hypothesis was rejected. Hence μ (the true mean of the movement data) is less than 3-mm. A two sample unpaired t-test (two sided) was carried out to show that the mean movement for the daily group data was not significantly different to the mean movement for the weekly data group. The p-value was above 0.05, the null hypothesis was not rejected. Hence μ_D (the true mean of the daily data) is equal to μ_W (the true mean of the weekly data). Conclusion There was no statistical difference when both imaging schedules were compared. Therefore weekly image guidance would be a more suitable type of imaging schedule. Weekly imaging would also reduce radiographer workload and any potential contaminant dose to the patient.Item A service evaluation on the influence of daily micro-enemas on interfraction prostate motion and acute bowel side effects in patients receiving external beam radiotherapy to the prostate(Queen Margaret University, 2016)Purpose: To evaluate the effect that daily micro-enemas had on interfraction prostate motion and acute bowel side effects during external beam radiotherapy (EBRT) to the prostate. Methods: 30 patients were recruited into two groups. 15 patients had used daily micro-enemas and 15 had not. Interfraction prostate motion was determined as the prostate shift relative to bony anatomy on each patient's daily cone beam computed tomography (CBCT) scans. These shifts were analysed for each of the patient's 37 treatments, therefore a total of 1100 fractions were included in total, with three sets of shifts being analysed for each fraction. These shifts were representative of the left/right (X), superior/inferior (Y) and anterior/posterior (Z) movements. Patients' side effects were observed by analysing changes to weekly bowel Radiation Therapy Oncology Group (RTOG) assessment scores to determine if a difference was observed between the two groups. Each patient had a baseline bowel RTOG assessment, followed by seven weekly RTOG scores. Therefore, each patient had eight scores making a total of 240 scores included in the service evaluation. Results: Interfraction prostate motion was significantly reduced in the enema group in the left/right (X) and anterior/posterior (Z) directions (p<0.05). In the superior/inferior (Y) direction the non-enema group had significantly smaller moves than the enema group (p<0.05). Bowel side effects were found to be significantly lower in the enema group when compared to the non-enema group (p<0.05). Conclusion: This service evaluation concluded that the use of daily micro-enemas was an effective way to reduce interfraction prostate motion and side effects in these groups of patients. A further prospective randomised study is advocated to validate these results before implementing a change in clinical protocols.Item A Comparison of Two Set-up Techniques for Tangential Breast Radiotherapy Treatments Using Portal Imaging and In-vivo Transit Dosimetry Data(Queen Margaret University, 2016)Background Accurate patient positioning for tangential breast treatments is crucial as this can influence the dose the patient receives. Two different set-up techniques have been examined for tangential breast radiotherapy treatments to determine which results in more accurate patient positioning and ultimately gives a better dose distribution across the target volume. Method This single centre service evaluation used a quasi-experimental design consisting of two technique groups; '5mm deviation' and the 'set to medial point' group. Each group contained 30 patients. Patients were found using relevant filters in Aria Report Manager and a method of stratified random sampling was used to find tangential treatments between 6-10MV. Image match analysis was carried out and any discrepancy in magnitude and direction between the Digitally Reconstructed Radiograph (DRR) and the integrated image noted and the corresponding transit dosimetry results were recorded from the DosimetryCheck program (Math Resolutions, LLC, Columbia, MD). Results The image match results for the 'set to medial point' technique showed 40% had a match discrepancy of 1mm compared to 3.3% in the '5mm deviation' group, only 3.3% of the matches in the 'set to medial point' group were above the 5mm accepted tolerance for analysing images offline compared to 23.3% in the '5mm deviation' group. The transit results for the '5mm deviation' group showed that two patients were outside the accepted +/- 10% tolerance and an additional five readings were over +/- 9%. In the 'set to medial point' group no in-vivo readings were outside +/- 10% and only 9.9% had readings above +/- 5%. A Spearman's Rho test showed a statistically significant, weak, positive monotonic correlation for the image match and transit results for the '5mm deviation' technique (rs,=0.358, n=30, p=0.052), in contrast to a non-significant, very weak correlation in the 'set to medial point' group (rs,=-0.041 n=30, p=0.830). Conclusions These findings illustrate that the 'set to medial point' technique provides a more stable patient set-up and also an improved dose distribution in comparison to the '5mm deviation' technique. Additionally, the DosimetryCheck program has proven its usefulness as a tool capable of identifying an unacceptable dose distribution when the patient's alignment differs significantly from the planned position.