paRTner: UK-Africa partnership for radiotherapy

Kate Ricketts and Gary Royle reflect on the first year of the paRTner project, a global health partnership for radiotherapy between the UK and Ghana

Management regime and habitat response influence abundance of regal fritillary (Speyeria idalia) in tallgrass prairie

The \u3e2,570,000-ha Flint Hills ecoregion of Kansas, USA, harbors the largest remaining contiguous tract of tallgrass prairie in North America, a unique system, as the remainder of North America’s tallgrass prairie has succumbed to development and conversion. Consequently, the loss and degradation of tallgrass prairie has reduced populations of many North American prairie-obligate species including the regal fritillary (Speyeria idalia) butterfly. Population abundance and occupied range of regal fritillary have declined \u3e99%, restricting many populations to isolated, remnant patches of tallgrass prairie. Such extensive decline has resulted in consideration of the regal fritillary for protection under the Endangered Species Act. Although it is widely accepted that management practices such as fire, grazing, and haying are necessary to maintain prairie ecosystems, reported responses by regal fritillary to these management regimes have been ambiguous.We tested effects of prescribed fire across short, moderate, and long fire-return intervals as well as grazing and haying management treatments on regal fritillary density. We also tested the relative influence of habitat characteristics created by these management regimes by measuring density of an obligate host plant (Viola spp.) and canopy cover of woody vegetation, grasses, forbs/ferns, bare ground, and litter. We found density was at least 1.6 times greater in sites burned with a moderate fire-return interval vs. sites burned with short and long fire-return intervals. Overall management regardless of fire-return interval did not have an effect on density. Percent cover of grass had the strongest positive association, while percent cover of woody vegetation had the greatest negative effect on density. Our results indicate that patch-burning is a viable and perhaps even ideal management strategy for regal fritillary in tallgrass prairie landscapes. Additionally, these results elucidate the importance of fire, particularly when applied at moderate-return intervals to regal fritillary, and corroborate a growing suite of studies that suggest fire is perhaps not as detrimental to populations of regal fritillary as previously believed

A methodology to extract outcomes from routine healthcare data for patients with locally advanced non-small cell lung cancer

BACKGROUND: Outcomes for patients in UK with locally advanced non-small cell lung cancer (LA NSCLC) are amongst the worst in Europe. Assessing outcomes is important for analysing the effectiveness of current practice. However, data quality is inconsistent and regular large scale analysis is challenging. This project investigates the use of routine healthcare datasets to determine progression free survival (PFS) and overall survival (OS) of patients treated with primary radical radiotherapy for LA NSCLC. METHODS: All LA NSCLC patients treated with primary radical radiotherapy in a 2 year period were identified and paired manual and routine data generated for an initial pilot study. Manual data was extracted information from hospital records and considered the gold standard. Key time points were date of diagnosis, recurrence, death or last clinical encounter. Routine data was collected from various data sources including, Hospital Episode Statistics, Personal Demographic Service, chemotherapy data, and radiotherapy datasets. Relevant event dates were defined by proxy time points and refined using backdating and time interval optimization. Dataset correlations were then tested on key clinical outcome indicators to establish if routine data could be used as a reliable proxy measure for manual data. RESULTS: Forty-three patients were identified for the pilot study. The manual data showed a median age of 67 years (range 46- 89 years) and all patients had stage IIIA/B disease. Using the manual data, the median PFS was 10.78 months (range 1.58-37.49 months) and median OS was 16.36 months (range 2.69-37.49 months). Based on routine data, using proxy measures, the estimated median PFS was 10.68 months (range 1.61-31.93 months) and estimated median OS was 15.38 months (range 2.14-33.71 months). Overall, the routine data underestimated the PFS and OS of the manual data but there was good correlation with a Pearson correlation coefficient of 0.94 for PFS and 0.97 for OS. CONCLUSIONS: This is a novel approach to use routine datasets to determine outcome indicators in patients with LA NSCLC that will be a surrogate to analysing manual data. The ability to enable efficient and large scale analysis of current lung cancer strategies has a huge potential impact on the healthcare system

A methodology to extract outcomes from routine healthcare data for patients with locally advanced non-small cell lung cancer

BACKGROUND: Outcomes for patients in UK with locally advanced non-small cell lung cancer (LA NSCLC) are amongst the worst in Europe. Assessing outcomes is important for analysing the effectiveness of current practice. However, data quality is inconsistent and regular large scale analysis is challenging. This project investigates the use of routine healthcare datasets to determine progression free survival (PFS) and overall survival (OS) of patients treated with primary radical radiotherapy for LA NSCLC. METHODS: All LA NSCLC patients treated with primary radical radiotherapy in a 2 year period were identified and paired manual and routine data generated for an initial pilot study. Manual data was extracted information from hospital records and considered the gold standard. Key time points were date of diagnosis, recurrence, death or last clinical encounter. Routine data was collected from various data sources including, Hospital Episode Statistics, Personal Demographic Service, chemotherapy data, and radiotherapy datasets. Relevant event dates were defined by proxy time points and refined using backdating and time interval optimization. Dataset correlations were then tested on key clinical outcome indicators to establish if routine data could be used as a reliable proxy measure for manual data. RESULTS: Forty-three patients were identified for the pilot study. The manual data showed a median age of 67 years (range 46- 89 years) and all patients had stage IIIA/B disease. Using the manual data, the median PFS was 10.78 months (range 1.58-37.49 months) and median OS was 16.36 months (range 2.69-37.49 months). Based on routine data, using proxy measures, the estimated median PFS was 10.68 months (range 1.61-31.93 months) and estimated median OS was 15.38 months (range 2.14-33.71 months). Overall, the routine data underestimated the PFS and OS of the manual data but there was good correlation with a Pearson correlation coefficient of 0.94 for PFS and 0.97 for OS. CONCLUSIONS: This is a novel approach to use routine datasets to determine outcome indicators in patients with LA NSCLC that will be a surrogate to analysing manual data. The ability to enable efficient and large scale analysis of current lung cancer strategies has a huge potential impact on the healthcare system

Investigation into the effects of high-Z nano materials in proton therapy

High-Z nano materials have been previously shown to increase the amount of dose deposition within the tumour due to an increase in secondary electrons. This study evaluates the effects of high-Z nano materials in combination with protons, and the impact of proton energy, nanoparticle material and concentration. These effects were studied in silico through Monte Carlo simulation and experimentally through a phantom study, with particular attention to macroscale changes to the Bragg peak in the presence of nanoparticles. Three nanoparticle materials were simulated (gold, silver and platinum) at three concentrations (0.01, 0.1 and 6.5 mg ml(-1)) at two clinical proton energies (60 and 226 MeV). Simulations were verified experimentally using Gafchromic film measurements of gold nanoparticles suspended in water at two available high concentrations (5.5 mg ml(-1) and 1.1 mg ml(-1)). A significant change to Bragg peak features was evident, where at 226 MeV and 6.5 mg ml(-1), simulations of gold showed a 4.7 mm longitudinal shift of the distal edge and experimentally at 5.5 mg ml(-1), a shift of 2.2 mm. Simulations showed this effect to be material dependent, where platinum having the highest physical density caused the greatest shift with increasing concentration. A dose enhancement of 6%  ±  0.05 and 5%  ±  0.15 (60 MeV and 226 MeV, respectively) was evident with gold at 6.5 mg ml(-1) to water alone, compared to the 21%  ±  0.53 observed experimentally as dose to film with 5.5 mg ml(-1) of gold nanoparticles suspended in water at 226 MeV. The introduction of nanoparticles has strong potential to enhance dose in proton therapy, however the changes to the Bragg peak distribution that occur with high concentrations need to be accounted for to ensure tumour coverage

The light curve of a transient X-ray source

The Ariel-V satellite monitored the X-ray light curve of A1524-62 almost continuously from 40 days prior to maximum light until its disappearance below the effective experimental sensitivity. The source exhibited maximum light on approximately 4 December 1974, at a level of 0.9 the apparent magnitude of the Crab Nebula in the energy band 3-6 keV. Although similar to previously reported transient sources with a decay time constant of approximately 2 months, the source exhibited an extended, variable pre-flare on-state of about 1 month at a level of greater than approximately 0.1 maximum light. The four bright (greater than 0.2 of the Crab Nebula) transient sources observed during the first half-year of Ariel-V operation are indicative of a galactic disk distribution, and a luminosity at maximum in excess of 10 to the 37th power ergs/sec

Implementation and evaluation of a transit dosimetry system for treatment verification

PURPOSE: To evaluate a formalism for transit dosimetry using a phantom study and prospectively evaluate the protocol on a patient population undergoing 3D conformal radiotherapy. METHODS: Amorphous silicon EPIDs were calibrated for dose and used to acquire images of delivered fields. The measured EPID dose map was back-projected using the planning CT images to calculate dose at pre-specified points within the patient using commercially available software, EPIgray (DOSIsoft, France). This software compared computed back-projected dose with treatment planning system dose. A series of tests were performed on solid water phantoms (linearity, field size effects, off-axis effects). 37 patients were enrolled in the prospective study. RESULTS: The EPID dose response was stable and linear with dose. For all tested field sizes the agreement was good between EPID-derived and treatment planning system dose in the central axis, with performance stability up to a measured depth of 18cm (agreement within -0.5% at 10cm depth on the central axis and within -1.4% at 2cm off-axis). 126 transit images were analysed of 37 3D-conformal patients. Patient results demonstrated the potential of EPIgray with 91% of all delivered fields achieved the initial set tolerance level of ΔD of 0±5-cGy or %ΔD of 0±5%. CONCLUSIONS: The in vivo dose verification method was simple to implement, with very few commissioning measurements needed. The system required no extra dose to the patient, and importantly was able to detect patient position errors that impacted on dose delivery in two of cases