Description of complex viewing geometries of fusion tomography diagnostics by ray-tracing

Ray-tracing techniques are applied to bolometry, a diagnostic where the finite collection volume is particularly sensitive to the machine and detector configuration. A technique is presented that can handle arbitrarily complex aperture and collimator geometries, neglecting reflection effects. Sight lines from the ASDEX Upgrade bolometer foils were ray-traced with a path tracing algorithm, where the optical path is represented by a statistical bundle of ray paths connecting the foil surface with the slit geometry. By using the full 3D machine model for the detector box and first wall, effects such as occlusion and vignetting were included in the calculation of the bolometer's étendue. Inversion matrices calculated with the ray-tracing technique were compared with the more conventional single-ray approach and shown to be naturally more constrained, requiring less regularisation. The two models were tested on a sample radiation scenario, and the common single-ray approximation is shown to be insufficient. These results are particularly relevant for the divertor where strong emission gradients may be present. The technique developed generalises well to arbitrarily complex viewing geometries and collimators, opening up a new design space for bolometer configurations that might not normally have been considered.

Correlation of next generation sequencing (NGS) of urine with tumor and plasma in patients with non-muscle invasive bladder cancer (NMIBC)

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Background: The current standard-of-care surveillance protocols for post-treatment NMIBC patients involve invasive procedures that result in poor patient compliance. Detection of recurrent NMIBC tumor DNA in plasma or urine would provide a less invasive alternative, and here we examine the feasibility of this approach by performing targeted NGS on tumor, plasma, and urine samples from NMIBC patients. Methods: 5 patients with untreated NMIBC (histology: Ta(n = 3), T1(n = 2)) have been analyzed to date. Urine and plasma samples were taken just prior to tumor resection. Samples were analyzed using a capture panel that includes common mutations found in > 80% of NMIBC patients. Coverage includes the promoter region of the TERT gene, the entire coding regions of KDM6A and FGFR3, and copy number variation in PD-L1 and JAK2. Results: Mutations were observed in all tumor samples, with the TERT -124C > T promoter mutation found in 4 patients (AF:16-84%) and the TERT -146C > T promoter mutation found in the other (AF:19%). Deleterious mutations were found in KDM6A for 4 patients, and FGFR3 activating mutations were found in 2 patients. Amplification of FGFR3 was seen in one sample. When the 4 matched pairs of urine and tumor samples were examined, all of the called mutations in tumor were also found in urine at similar allele frequencies. This includes the detection of gene copy alterations. No such mutations were observed in plasma samples despite extensive sequencing ( > 2000 unique read coverage). Conclusions: These data show that canonical NMIBC mutations are readily detectable in urine and correlate well with tumor, suggesting that NMIBC tumors shed prolifically into urine, and indicate that further investigation of NGS sequencing of urine as a means of detecting NMIBC recurrence is warranted.

Liquid biopsy in the clinic: A prospective study of plasma circulating tumor DNA (ctDNA) next generation sequencing (NGS) in patients with advanced non-small cell lung cancers to match targeted therapy

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Background: Liquid biopsy for plasma ctDNA NGS is a rapidly evolving science. Plasma ctDNA assays are commercially available and are increasingly adopted in the community with a paucity of evidence-based guidance. We set out to study the optimal timing and utility of plasma ctDNA NGS in clinic. Methods: Pts with advanced NSCLC who were driver unknown, defined as not having prior tissue NGS or clinical concern for tumor heterogeneity that may affect treatment decisions, were eligible. Peripheral blood was collected in a Streck tube (10mL), DNA extracted, and subjected to a bias-corrected hybrid-capture 21 gene targeted NGS assay in a CLIA lab with unique reads at 3000x and sensitive detection at variant allele frequency above 0.1% (ResolutionBio Bellevue, WA). Pts also had concurrent tissue NGS via MSK IMPACT. Clinical endpoints included detection of oncogenic drivers in plasma, ability to match pts to targeted therapy, concordance and turnaround time of plasma and tissue NGS. Results: Forty-one pts were prospectively accrued. Plasma ctDNA detected an oncogenic driver in 39% (16/41) of pts, of whom 17% (7/41) were matched to targeted therapy; including pts matched to clinical trials for HER2 exon 20 insertionYVMA, BRAF L597Q and MET exon14. Mean turnaround time for plasma was 7 days (4-12) and 28 days (20-43) for tissue. Plasma ctDNA was detected in 56% (23/41) of pts; detection was 40% (8/20) if blood was drawn on active therapy and 71% (15/21) if drawn off therapy, either at diagnosis or progression (Odds ratio 0.28, 95% CI 0.06 - 1.16; p = 0.06). All pts had concurrent tissue NGS; of the 10 samples resulted, there was 100% driver concordance between tissue and plasma in pts drawn off therapy. Conclusions: In pts who were driver unknown or who had clinical concern for tumor heterogeneity, plasma ctDNA NGS identified a variety of oncogenic drivers with a short turnaround time and matched them to targeted therapy. Plasma ctDNA detection was more frequent at diagnosis of metastatic disease or at progression. A positive finding of an oncogenic driver in plasma is highly specific, but a negative finding may still require tissue biopsy.

Mapping and evaluation of physical activity interventions for school-aged children

OBJECTIVES

A high degree of de-regulation, organisational fragmentation and funding cuts throughout UK schools in recent years has obscured the definitive structure and effectiveness of physical activity (PA) provision offered to children. This pilot study aimed to map the current structure and context of PA provision offered to school children in Southampton, and its alignment with existing empirical evidence about the likely effectiveness of such interventions.

STUDY DESIGN

Utilising a qualitative approach, the study focused upon school-based PA provision, since this setting was conjectured to show greater diversity when compared to settings outside of school, lending itself to further interventions than non-school PA provision.

METHODS

Interventions offered across nine schools (three junior, two primary, four secondary) were investigated and mapped through semi-structured interviews. Findings were benchmarked against other cities similar to Southampton in indices of multiple deprivation status via interviews with city council workers.

RESULTS

Interviews highlighted only three formal PA specific interventions currently operating, and a hand full of informal interventions. Limited PA provision was attributed to a lack of time, money, and priority devoted towards PA within schools. Considerable disparity exists between the high prevalence of sport-oriented provision compared with the low prevalence of PA specific provision. Interviews with Portsmouth and Bristol city councils suggest that such findings may not be unique to Southampton.

CONCLUSIONS

In contrast to the extensive literature base detailing numerous PA interventions in school-aged children, our data suggest that a very small amount of such knowledge appears to translate into PA provision offered in Southampton schools. Our data highlight a significant discrepancy between sport and PA provision across schools. It is possible that the inability to successfully differentiate between sport and PA may present a further obstacle to the successful uptake of PA in the future. An extension of the PA mapping carried out, both countywide and nationally, provides a possible avenue for future research to confirm or contrast these initial insights.

Component reductions in oxygen delivery generate variable haemodynamic and stress hormone responses

BACKGROUND

In clinical practice, global oxygen delivery (DO2) is often considered as a whole; however pathological and adaptive responses after a decrease in individual constituents of the DO2 equation (cardiac output, haemoglobin, oxyhaemoglobin saturation) are likely to be diverse. We hypothesized that an equivalent decrease in DO2 after reductions in each separate component of the equation would result in different haemodynamic, tissue oxygenation, and stress hormonal responses.

METHODS

Anaesthetized, fluid-resuscitated male Wistar rats were subjected to circulatory, anaemic, or hypoxic hypoxia (by haemorrhage, isovolaemic haemodilution, and breathing a hypoxic gas mix, respectively), produced either rapidly over 5 min or graded over 30 min, to a targeted 50% decrease in global oxygen delivery. Sham-operated animals acted as controls. Measurements were made of haemodynamics, skeletal muscle tissue oxygen tension, blood gas analysis, and circulating stress hormone levels.

RESULTS

Whereas haemorrhage generated the largest decrease in cardiac output, and the greatest stress hormone response, haemodilution had the most marked effect on arterial pressure. In contrast, rapid hypoxaemia produced a minor impact on global haemodynamics yet induced the greatest decrease in regional oxygenation. A greater degree of hyperlactataemia was observed with graded insults compared with those administered rapidly.

CONCLUSIONS

Decreasing global oxygen delivery, achieved by targeted reductions in its separate components, induces varying circulatory, tissue oxygen tension, and stress hormone responses. We conclude that not all oxygen delivery is the same; this disparity should be emphasized in classical teaching and re-evaluated in patient management.

Evidence-based guideline recommendations on the use of positron emission tomography imaging in head and neck cancer

AIMS

To provide evidence-based practice guideline recommendations on the use of fluoro-2-deoxy-D-glucose positron emission tomography (PET) for diagnosis, staging and assessing treatment response, restaging or recurrence of head and neck cancer.

MATERIALS AND METHODS

A systematic review by Facey et al. (Health Technology Assessment 2007;11(44):iii-iv, xi-267) was used as the evidence base for recommendation development. As the review was limited to August 2005, the evidence base was updated to July 2011 using the same search strategies for MEDLINE and EMBASE used in the original review. The authors of the current systematic review drafted recommendations, which were reviewed, adapted and accepted by consensus by the Ontario provincial Head and Neck Disease Site Group and a special meeting of clinical experts.

RESULTS

The results of the Facey et al. review for head and neck cancer included five other systematic reviews and 31 primary studies. The 2005 to 2011 update search included four additional systematic reviews and 53 primary studies. Recommendations were developed based on this evidence and accepted by consensus.

CONCLUSIONS

PET is recommended in the M and bilateral nodal staging of all patients with head and neck squamous cell carcinoma where conventional imaging is equivocal, or where treatment may be significantly modified. PET is recommended in all patients after conventional imaging and in addition to, or prior to, diagnostic panendoscopy where the primary site is unknown. PET is recommended for the staging and assessment of recurrence of patients with nasopharyngeal carcinoma if conventional imaging is equivocal. PET is recommended for restaging patients who are being considered for major salvage treatment, including neck dissection.