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Abstract Droplet evaporation characterization, although of great significance, is still challenging. The recently developed phase rainbow refractometry (PRR) is proposed as an approach to measuring the droplet temperature, size as well as evaporation rate simultaneously, and is applied to a single flowing n-heptane droplet produced by a droplet-on-demand generator. The changes of droplet temperature and evaporation rate after a transient spark heating are reflected in the time-resolved PRR image. Results show that droplet evaporation rate increases with temperature, from −1.28 × 10 − 8 m2/s at atmospheric 293 K to a range of (−1.5, −8) × 10 − 8 m2/s when heated to (294, 315) K, agreeing well with the Maxwell and Stefan–Fuchs model predictions. Uncertainty analysis suggests that the main source is the indeterminate gradient inside droplet, resulting in an underestimation of droplet temperature and evaporation rate. With the demonstration on simultaneous measurements of droplet refractive index as well as droplet transient and local evaporation rate in this work, PRR is a promising tool to investigate single droplet evaporation in real engine conditions. [ABSTRACT FROM AUTHOR]

Abstract Aim and background The change in the prostate size for radiotherapy has not yet been elucidated. The coverage of radiation dose is affected by changes in the prostate size. We evaluated the changes in the prostate, rectum, and bladder wall sizes during IMRT of fraction 2 Gy/day using MRI. Materials and methods Twenty-four patients with prostate cancer were enrolled in this study. MRI was performed at three time points. While the initial MRI was performed before the start of radiotherapy (RT), the second MRI was performed at 38 Gy (range: 36–40 Gy), which represented the halfway point of the RT course. The last MRI was performed on the day of completion of the RT course (76 Gy; range: 74–78 Gy). We estimated the prostate, rectum, and bladder wall sizes at three time points. Results We observed no significant difference between the estimated sizes of the prostate during RT in all three phases. In addition, the volume of the rectal wall remained unchanged in all phases. However, the volume of the bladder wall significantly decreased from the initial to the last time points. Furthermore, the standard deviation (SD) obtained by subtracting the final size from the initial one was large (mean, 30.1; SD, 10.1). Conclusions The volume of the bladder wall decreased during IMRT. The range of subtraction of the volume of the bladder wall was extensive. Thus, the estimation of the bladder wall may be useful to reduce the inter-fraction variation. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: The aim of this study was to quantify the effect of overlapping reconstruction on the precision and accuracy of lung nodule volume estimates in a phantom computed tomographic (CT) study. Materials and Methods: An anthropomorphic phantom was used with a vasculature insert on which synthetic lung nodules were attached. Repeated scans of the phantom were acquired using a 64-slice CT scanner. Overlapping and contiguous reconstructions were performed for a range of CT imaging parameters (exposure, slice thickness, pitch, reconstruction kernel) and a range of nodule characteristics (size, density). Nodule volume was estimated with a previously developed matched-filter algorithm. Results: Absolute percentage bias across all nodule sizes (n = 2880) was significantly lower when overlapping reconstruction was used, with an absolute percentage bias of 6.6% (95% confidence interval [CI], 6.4–6.9), compared to 13.2% (95% CI, 12.7–13.8) for contiguous reconstruction. Overlapping reconstruction also showed a precision benefit, with a lower standard percentage error of 7.1% (95% CI, 6.9–7.2) compared with 15.3% (95% CI, 14.9–15.7) for contiguous reconstructions across all nodules. Both effects were more pronounced for the smaller, subcentimeter nodules. Conclusions: These results support the use of overlapping reconstruction to improve the quantitative assessment of nodule size with CT imaging. [ABSTRACT FROM AUTHOR]