MSc in Radiotherapy and Oncology
Permanent URI for this collectionhttps://eresearch.qmu.ac.uk/handle/20.500.12289/7225
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Item To investigate role of stereotactic radiosurgery as a first and primary treatment in the management of Arteriovenous Malformations in an Adult Population.(2018)Stereotactic radiosurgery (SRS) is widely used as treatment option for brain arteriovenous malformations (BAVM), however the extent of it’s role remains undefined. Research to date is gathered collectively from groups which consider SRS, embolisation and microsurgery as a single interventional technique or from reports in which SRS is provided as a secondary treatment. The evidence for SRS is representative of an accumulation of techniques and thus inconclusive for the individual contribution of SRS. The aim of the systematic review was to establish the role of SRS as a primary treatment in the obliteration of AVMs. An extensive literature search was conducted on Embase, CINAHL and Pudmed databases. This was followed by a rigid, pre-defined screening of the collected literature. For all included studies SRS was provided as a first and primary treatment for multiple grade BAVMs in an adult population. Statistical analysis was completed using Comprehensive meta-analysis software and was also accompanied by tabular summary and narrative analysis. 11 Studies were included in the final analysis. Despite an I² statistic of 71.87 for heterogeneity results indicated a trend supporting the role of SRS as a treatment, particularly for the obliteration of smaller BAVMs. Due to a small sample size in result analysis it was advised to interpret results with caution. Considering the non-invasive approach of SRS it may also hold a major advantage in treatment of large, deep BAVMs (IRSA 2009). The review identified the need to establish correct dose contributions for various BAVM sizes and grades. It also revealed that consistent reporting is strongly advised particularly for considerations such as age and pre-treatment embolisation. Future research is vital and necessary to establish the therapeutic advantage SRS may play in AVM obliteration and to compare its efficacy against alternative treatment modalities such as embolisation or microsurgery.Item A COMPARISON OF SOFT TISSUE AND BONE TO VERIFY TREATMENT POSITION FOR LUNG CANCER PATIENTS RECEIVING RADICAL RADIOTHERAPY.(2018)Introduction Two-dimensional (2D) kilovoltage (kV) imaging is currently used in the department for positioning lung cancer patients prior to non-stereotactic ablative radiotherapy (SABR). With enhanced visualisation of soft tissue using three-dimensional cone-beam computed tomography (CBCT), its use in non-SABR lung radiotherapy is highly recommended. Prior to its introduction in the department, matching to bone, carina and tumour was assessed retrospectively in CBCTs collected as part of a service evaluation and compared to the current 2D kV protocol of matching to bones. This determined which anatomical landmark provided the optimum treatment accuracy. The feasibility of introducing CBCT imaging as routine protocol was also assessed. Method In this quantitative study, five radiographers conducted automatic and manual matches to bone, carina and tumour in 88 CBCTs of 20 patients. For each of the 2600 match positions, couch shifts were recorded in the anterior/posterior, left/right and superior/inferior directions. Tumour coverage was graded at each match position according to target volume margins. The level of agreement between automatic and manual matches and the percentage of couch errors out with clinical tolerance (5mm) were calculated for each matching method. The feasibility of CBCT imaging was assessed by examining inter-observer reliability, reporting difficulties in the matching process and comparing the time taken to match to CBCTs compared with 2D kV imaging. Results Paired t-tests demonstrated a highly significant difference in the couch position when tumour was matched to instead of bone (P<0.001). Tumour matching detected the highest proportion of set-up errors out width tolerance (26.1%), followed by carina (19.05%) and bone (18.41%). Bland-Altman analysis demonstrated tumour matching had the lowest levels of automatic and manual matching agreement. Using the intraclass correlation coefficient (ICC), all matching methods demonstrated either good or excellent inter-observer reliability (ICC 0.871-0.957). Problematic matches were reported in 20% of matches and timings were comparable (four minutes) with 2D kV imaging. Conclusion This study supports the introduction of CBCT imaging and matching directly to tumour as routine protocol for all non-SABR lung cancer patients. Visual inspection of the tumour is highly recommended after automatic matching to ensure target coverage, with the use of the carina as a guide when problematic matching occurs.Item CAN IN-VIVO DOSIMETRY ENHANCE CURRENT PRACTICE IN VMAT HEAD AND NECK TREATMENT? A retrospective service evaluation assessing the use of in-vivo dosimetry as a tool to assist in the implementation of an interventional rescan.(Queen Margaret University, 2017)Background Patient positioning during a course of external beam radiotherapy (EBRT) can be verified and corrected on a daily basis using image guided radiotherapy (IGRT) which can account for patient misalignment but not for dose discrepancies due to anatomical changes. The use of adaptive radiotherapy (ART) where the plan is adapted to the anatomical changes during the course of treatment due to these changes could be enhanced by utilising computed tomography (CT) geometrical data and dosimetric data. This retrospective service evaluation aims to address this by assessing the use of in-vivo dosimetry as a tool to implement ART. Methods The methodological approach to this small scale service evaluation was quantitative. Random sampling technique was applied as the subjects were chosen from a population who received treatment to head and neck using VMAT technique. Retrospective in-vivo dosimetry analysis was carried out on patients who underwent an interventional re-scan during treatment to their head and neck. Deformable image registration was applied to the weekly cone beam computed tomography (CBCT's) in order to assess the dose to the 'actual' patient anatomy. The dose was calculated as a percentage dose difference (%DD) between planned and actual anatomy for comparative purposes in this study to assess the evaluation outcome. Results The %DD between the planned anatomies as measured by the in-vivo software versus the dose calculated using the treatment planning system at all reference points for each of the eight patients were calculated. The resultant means of patients 1-5 (rescanned and not re-planned) versus patients 6-8 (re-planned) were analysed for significant difference at all reference points. The resultant p-value at reference points C1 and C3 was 0.08 and 0.07 respectively. C5 position compared similarly to the isocentre position with a value of 0.25 whereas C7 was poorest with a value of 0.62, due to the poor accuracy of DC at this point. Conclusion Statistical results proved a weak relationship between the %DD of the deformed (changed) and planned (presumed unchanged) anatomies meaning ART could not be implemented based on these results. Whether in-vivo dosimetry can be used to aid the decision to implement a rescan was proved to be ineffective. There was no significant difference detected between the rescanned and not re-planned patients and the re-planned patient.Item TURNING THE CORNER: A MIXED METHODS INVESTIGATION INTO THE RADIOTHERAPY INFORMATION NEEDS OF GPS(Queen Margaret University, 2017)Background: NHS cancer strategy emphasises delivery of integrated care across primary and secondary environments. However, previous studies highlight a radiotherapy knowledge gap amongst GPs. Aims: To identify the radiotherapy information needs of GPs and explore how these needs can best be met by a large regional cancer centre. Methods: A 10-item questionnaire developed by the researcher was distributed via email to all 123 practice managers in a single health board. A subsequent email to practice managers was used to recruit volunteers for semi-structured interviews to add depth and detail to questionnaire findings. Results: 93 valid questionnaires were received in the four week data collection period. Although 95% had cared for a patient undergoing radiotherapy, only 4% agreed that radiotherapy information was easy to access. Confidence in indications for emergency radiotherapy (65%) and indications for palliative radiotherapy (64%) were highest, while confidence in how radiotherapy interacts with other treatments (2%) and in managing acute side effects beyond skin reactions (14%) were lowest. 70% of GPs reported having radiotherapy education, and this was correlated with confidence in explaining radiotherapy (p= 0.013), discussing long-term side effects (p= 0.036) and indications for palliative radiotherapy (p=0.02). GPs emphasised a preference for easily accessible electronic information, and suggested the addition of radiotherapy information to an existing platform. However, they also emphasised a perceived division between specialist and primary care. Conclusion: The integrated care outlined in NHS cancer strategy is challenged in practice by lack of knowledge and an underlying perception among GPs of fragmentation of care. This affects patients and should be addressed as a matter of priority both with straightforward electronic information provision and more complex strategic interventions.Item A Comparison of thermoplastic and 3D printed beam directional shells on viability for external beam radiotherapy and user experience(Queen Margaret University, 2017)Background: The precision of a patient's set-up for the accurate delivery of radiotherapy is paramount. For patients receiving radiotherapy for head and neck cancer it is particularly critical due to the need to prescribe the maximum therapeutic dose to the tumour while sparing normal tissue in very close proximity. Through advances in new technology three-dimensional printing gives the potential for creating an anatomically precise beam directional shell (BDS) directly from a three-dimensional computer model of the patient. Purpose: The aim of this study is to determine the viability of using three-dimensionally printed BDSs by comparing them to the currently used thermoplastic BDSs. Materials and methods: A direct comparison of three-dimensional and thermoplastic BDSs will be assessed. Seventeen healthy volunteers had both BDSs created and a retrospective isocentre positioned on the masks to be used as a baseline for set up. The retrospective isocentre mark allowed left-right, superior-inferior, anterior-posterior alignment and rotation to be assessed over four sessions. After each session of wearing the BDS, the volunteers immediately completed a State Trait Anxiety Inventory (STAI) Part 1 to assess their emotional experience of that particular BDS. Results and conclusion: The data was assessed for normality and homogeneity. If the data was considered normally distributed and homogeneous then a two-way repeated measures Analysis of Variance was performed. If it was not normally distributed then a non-parametric Friedman and Man Whitney U test was used. It was found that there was no significant difference in the external reproducibility of the 3D printed compared to the thermoplastic BDS for the Vertical, Longitudinal and Lateral couch parameters. There was however a statistically significant difference for the Rotational variable. The results obtained from the STAI Part 1 suggested that the thermoplastic BDS produced significantly higher scores in anxiety and distress compared to the 3D printed BDS. The results obtained give encouraging evidence to indicate that 3D printed BDSs could be a viable immobilisation device used for patients requiring EBRT to the head and neck region.