Evaluating the impact of service delivery initiatives on patients’ waiting times in diagnostic radiology: a mixed methods study

This thesis describes the impact of service delivery initiatives (SDIs) on patients’ waiting times within radiology departments. A systematic review of the literature (71 studies included) found the following broad type of SIDs: extended scope practice, quality management, productivity-enhancing technologies, outsourcing, pay-for-performance and multiple interventions. Ninety-six percent of the studies used either the pre- and post-intervention without control or the post-intervention only designs; but these designs are fundamentally weak and prone to bias. Furthermore, this thesis also described a case-study for the evaluation of the impact on patients’ waiting times of a 320-slice computed tomography (CT) scanner, speech recognition reporting and extended-working-hours within the Birmingham Heartlands Hospital (Heart of England NHS Foundation Trust), Birmingham. The evaluation combined the interrupted time series (ITS) design and qualitative interviews with healthcare professionals in a mixed methods approach. The mixed methods approach leverages the strengths of the quantitative and qualitative methods, so that the triangulation of the findings of one research method might be strengthened when supported by the findings of the other research method. The thesis used a distinctive implementation of ITS segmented regression which accounts for the changing trends of patients waiting times – an approach referred to as ITS ‘segmented spline’ regression

Estimates of Paediatric Doses for Common Radiographic Procedures in some Nigerian Hospitals

Purpose: To determine and establish doses in paediatric radiography for hospitals which have no previous data. Materials and Methods: X-ray examination data were collected and used as input in a dose calculation software (DOSECAL, from St. Georges’ Hospital, London) to obtain absorbed doses to the skin (entrance surface dose, ESD) as well as organ and effective doses. The study covered five common radiological examinations. Results: Entrance surface and effective doses were found to be generally higher in agreement with an earlier study using thermoluminescent dosimetry, while organ doses were lower than the values for similar age groups in the literature. Causes of these high doses are attributed to the type, age and conditions of radiographic equipment, radiographic exposure factors (low kVp - which also accounts for low organ doses, and high mAs in some cases), film processing conditions and lack of quality assurance programmes. Suggestions and recommendations are outlined for dose reduction to within recommended international limits. Conclusion: Doses obtained in this study will serve as a basis for comparison of future studies in the area

Phylogenetic ctDNA analysis depicts early-stage lung cancer evolution.

The early detection of relapse following primary surgery for non-small-cell lung cancer and the characterization of emerging subclones, which seed metastatic sites, might offer new therapeutic approaches for limiting tumour recurrence. The ability to track the evolutionary dynamics of early-stage lung cancer non-invasively in circulating tumour DNA (ctDNA) has not yet been demonstrated. Here we use a tumour-specific phylogenetic approach to profile the ctDNA of the first 100 TRACERx (Tracking Non-Small-Cell Lung Cancer Evolution Through Therapy (Rx)) study participants, including one patient who was also recruited to the PEACE (Posthumous Evaluation of Advanced Cancer Environment) post-mortem study. We identify independent predictors of ctDNA release and analyse the tumour-volume detection limit. Through blinded profiling of postoperative plasma, we observe evidence of adjuvant chemotherapy resistance and identify patients who are very likely to experience recurrence of their lung cancer. Finally, we show that phylogenetic ctDNA profiling tracks the subclonal nature of lung cancer relapse and metastasis, providing a new approach for ctDNA-driven therapeutic studies

Representative sequencing: Unbiased sampling of solid tumor tissue

International audienceAlthough thousands of solid tumors have been sequenced to date, a fundamental under-sampling bias isinherent in current methodologies. This is caused by a tissue sample input of fixed dimensions (e.g., 6 mmbiopsy), which becomes grossly under-powered as tumor volume scales. Here, we demonstrate representative sequencing (Rep-Seq) as a new method to achieve unbiased tumor tissue sampling. Rep-Seq uses fixed residual tumor material, which is homogenized and subjected to next-generation sequencing. Analysis of intratumor tumor mutation burden (TMB) variability shows a high level of misclassification using current single-biopsy methods, with 20% of lung and 52% of bladder tumors having at least one biopsy with high TMB butlow clonal TMB overall. Misclassification rates by contrast are reduced to 2% (lung) and 4% (bladder) when a more representative sampling methodology is used. Rep-Seq offers an improved sampling protocol for tumor profiling, with significant potential for improved clinical utility and more accurate deconvolution of clonal structure