Background
In radical radiochemotherapy (RCT) of inoperable non-small-cell lung cancer (NSCLC) typical prognostic factors include T- and N-stage, while there are still conflicting data on the ...prognostic relevance of gross tumor volume (GTV) and particularly its changes during RCT. The NCT03055715 study of the Young DEGRO working group of the German Society of Radiation Oncology (DEGRO) evaluated the prognostic impact of GTV and its changes during RCT.
Methods
A total of 21 university centers for radiation oncology from five different European countries (Germany, Switzerland, Spain, Belgium, and Austria) participated in the study which evaluated
n
= 347 patients with confirmed (biopsy) inoperable NSCLC in UICC stage III A/B who received radical curative-intent RCT between 2010 and 2013. Patient and disease data were collected anonymously via electronic case report forms and entered into the multi-institutional RadPlanBio platform for central data analysis. GTV before RCT (initial planning CT, GTV1) and at 40–50 Gy (re-planning CT for radiation boost, GTV2) was delineated. Absolute GTV before/during RCT and relative GTV changes were correlated with overall survival as the primary endpoint. Hazard ratios (HR) of survival analysis were estimated by means of adjusted Cox regression models.
Results
GTV1 was found to have a mean of 154.4 ml (95%CI: 1.5–877) and GTV2 of 106.2 ml (95% CI: 0.5–589.5), resulting in an estimated reduction of 48.2 ml (
p
< 0.001). Median overall survival (OS) was 18.8 months with a median of 22.1, 20.9, and 12.6 months for patients with high, intermediate, and low GTV before RT. Considering all patients, in one survival model of overall mortality, GTV2 (2.75 (1.12–6.75,
p
= 0.03) was found to be a stronger survival predictor than GTV1 (1.34 (0.9–2,
p
> 0.05). In patients with available data on both GTV1 and GTV2, absolute GTV1 before RT was not significantly associated with survival (HR 0–69, 0.32–1.49,
p
> 0.05) but GTV2 significantly predicted OS in a model adjusted for age, T stage, and chemotherapy, with an HR of 3.7 (1.01–13.53,
p
= 0.04) per 300 ml. The absolute decrease from GTV1 to GTV2 was correlated to survival, where every decrease by 50 ml reduced the HR by 0.8 (CI 0.64–0.99,
p
= 0.04). There was no evidence for a survival effect of the relative change between GTV1 and GTV2.
Conclusion
Our results indicate that independently of T stage, the re-planning GTV during RCT is a significant and superior survival predictor compared to baseline GTV before RT. Patients with a high absolute (rather than relative) change in GTV during RT show a superior survival outcome after RCT.
The aim of the study was to implement an abdominal CT angiography protocol using 100 kVp and to compare SNR and CNR, as well as subjective image quality, to a standard CT angiography protocol using ...120 kVp on a 16 detector-row CT scanner. Forty-eight patients were referred for routine abdominal CT angiography on a 16 detector-row CT scanner. Patients were scanned using either 120 or 100 kVp at constant mAs settings. Vessel opacification was provided by automated contrast injection using similar injection protocols. Density measurements were performed along the aorto-iliac axis with SNR and CNR calculation. In addition, the estimated effective patient radiation dose was calculated. Results of both protocols were compared. The 100-kVp protocol (432+/-80 HU) showed a significantly higher vessel density than the 120-kVp (333+/-90 HU; P<0.001) protocol, corresponding to an average increase in signal intensity of 30.7%. SNR (36.0 vs 37.0) and CNR (31.1 vs 31.7) for the 100-kV protocol were not significantly lower that those for the standard protocol (P=0.79 and P=0.87), whilst the average estimated dose was significantly lower using the 100-kVp protocol (6.7+/-0.4 vs 10.1+/-1.2 mSv; P<0.0001). Tube kVp reduction from 120 to 100 kVp allows for significant reduction of patient dose in abdominal CT angiography, without significant change in SNR,CNR and image quality.
The purpose of our study was to evaluate the dose reduction potential of combined online (x- and y-axes) and topogram-based (l) X-ray tube current modulation in CT colonography in a screening ...population.
Eighty asymptomatic individuals underwent CT colonography screening for colon polyps. A 16-MDCT scanner (Somatom Sensation 16) was used. Forty patients were examined at 120 kVp and 120 effective mAs (supine) and 40 effective mAs (prone) using online x- and y-axis tube current modulation. Another 40 patients were scanned using combined x-, y-, and z-axis tube current modulation. Individual patient radiation exposure was determined using the dose-length product. Image noise was determined by Hounsfield unit measurements in the colonic lumen at four anatomic levels. Image quality was rated on a 5-point confidence scale by two independent reviewers. The unpaired Student's t test (for radiation dose, image noise) and Wilcoxon's test (for image quality) were used to test for statistically significant differences between these values.
Radiation dose was significantly lower in the patient group scanned with x-, y-, and z-axis tube current modulation than in the group scanned with x- and y-axis tube current modulation (supine: 4.24 vs 6.50 mSv, p < 0.0001; prone: 1.61 vs 2.38 mSv, p < 0.0001). Radiation dose was reduced by 35% (supine) and 33% (prone). No statistically significant difference was seen in overall image noise (supine: 15.9 vs 16.3 H, p = 0.13; prone: 23.5 vs 24.8 H, p = 0.44) or image quality (supine: 4.6 vs 4.5, p = 0.62; prone: 3.5 vs 3.6, p = 0.54).
Combined x-, y-, and z-axis tube current modulation leads to a significant reduction of radiation exposure in CT colonography without loss of image quality.
We report on the morphological aspects of thin films prepared from a blue–green light‐emitting conjugated polymer, (methyl‐substituted ladder‐type poly(p‐phenylene, mLPPP)), blended with a ...solid‐state electrolyte composed either by a crown ether, dicyclohexano‐18‐crown‐6 (DCH18C6), or a high‐molecular‐weight poly(ethylene oxide) (HMWPEO), and a Li salt, lithium trifluoromethanesulfonate (LiCF3SO3, Li triflate (LiTf)), as they have been successfully applied in light‐emitting electrochemical cells (LECs). The surface morphologies of the blend layers were investigated using atomic force microscopy (AFM) in tapping mode, and the ion distribution was probed using X‐ray analysis by means of energy‐dispersive X‐ray spectrometry (EDXS) in the scanning electron microscope (SEM). We show that the two different phase‐separation processes, the complexation tendencies of the ionic species as well as the ionic transport numbers, have tremendous influence on the performances of the corresponding LECs, revealing either rectifying or symmetric optoelectronic characteristics in forward and reverse bias directions. This opens up new possibilities for tuning the optoelectronic properties of ion‐supported organic electronic devices.
Light‐emitting electrochemical cells (LECs) operate via the accumulation of ionic species provided by the electrolyte at the electrodes. It is shown here that different conjugated polymer/electrolyte phase‐separation processes (see Figure), in combination with the complexation tendencies of the ionic species and the ionic transport numbers, influence the performance of LECs. This opens up new strategies for tuning the optoelectronic properties of ion‐supported organic electronic devices.
Purpose
Assessment of calcium scoring (Ca-scoring) on a 64-slice multi-detector computed tomography (MDCT) scanner, a dual-source computed tomography (DSCT) scanner and an electron beam tomography ...(EBT) scanner with a moving cardiac phantom as a function of heart rate, slice thickness and calcium density.
Methods and materials
Three artificial arteries with inserted calcifications of different sizes and densities were scanned at rest (0 beats per minute) and at 50–110 beats per minute (bpm) with an interval of 10 bpm using 64-slice MDCT, DSCT and EBT. Images were reconstructed with a slice thickness of 0.6 and 3.0 mm. Agatston score, volume score and equivalent mass score were determined for each artery. A cardiac motion susceptibility (CMS) index was introduced to assess the susceptibility of Ca-scoring to heart rate. In addition, a difference (Δ) index was introduced to assess the difference of absolute Ca-scoring on MDCT and DSCT with EBT.
Results
Ca-score is relatively constant up to 60 bpm and starts to decrease or increase above 70 bpm, depending on scoring method, calcification density and slice thickness. EBT showed the least susceptibility to cardiac motion with the smallest average CMS-index (2.5). The average CMS-index of 64-slice MDCT (9.0) is approximately 2.5 times the average CMS-index of DSCT (3.6). The use of a smaller slice thickness decreases the CMS-index for both CT-modalities. The Δ-index for DSCT at 0.6 mm (53.2) is approximately 30% lower than the Δ-index for 64-slice MDCT at 0.6 mm (72.0). The Δ-indexes at 3.0 mm are approximately equal for both modalities (96.9 and 102.0 for 64-slice MDCT and DSCT respectively).
Conclusion
Ca-scoring is influenced by heart rate, slice thickness and modality used. Ca-scoring on DSCT is approximately 50% less susceptible to cardiac motion as 64-slice MDCT. DSCT offers a better approximation of absolute calcium score on EBT than 64-slice MDCT when using a smaller slice thickness. A smaller slice thickness reduces the susceptibility to cardiac motion and reduces the difference between CT-data and EBT-data. The best approximation of EBT on CT is found for DSCT with a slice thickness of 0.6 mm.
We present an image reconstruction approach and a performance evaluation for ECG-gate cardiac spiral scanning with recently introduced 16-slice CT equipment. We present an extension of the Adaptive ...Cardio Volume (ACV) reconstruction approach for ECG-gated multislice spiral scanning. We discuss the image z reformation introduced to control the spiral slice width of the final images and give an overview of the reformation functions chosen. We investigate image quality and discuss the maximum number of slices that can be reconstructed without severe cone-beam artifacts. Slice sensitivity profiles (SSPs) and transverse resolution are evaluated as a function of the patient’s heart rate. We demonstrate the influence of slice width on the visualization of stents and plaques and show the impact of reduced gantry rotation time (0.42 s) on temporal resolution. Deviating from general purpose spiral scanning cone-beam reconstruction is not required for ECG-gated cardiac CT with up to 16 slices. Using the ACV approach with image reformation, SSPs are well defined and independent of the patient’s heart rate. With 0.75 mm collimated slice width, the measured full width at half-maximum (FWHM) of the smallest reconstructed slice is about 0.83 mm. Using this slice width and overlapping image reconstruction, cylindrical holes 0.6–0.7 mm in diameter can be resolved in a z-resolution phantom. Adequate visualization of the coronary arteries requires reconstruction slice widths not larger than 1.5 mm. Visualization of stents and severe calcifications is significantly improved with sub-mm slice width. Experimental evidence for the theoretically predicted temporal resolution and for the variation of temporal resolution depending on the position in the field of measurement (FOM) is presented. With 0.42 s gantry rotation temporal resolution reaches its optimum of 105 ms in the center of the FOM at 81 bpm. First scans on human subjects demonstrate the potential to expand the range of heart rates accessible to routine clinical examinations. A 16-slice platform can cover the heart with sub-mm slices within short breath-hold times, allowing for improved cardiac imaging due to isotropic sub-mm spatial resolution.
Asymmetric division is crucial for embryonic development and stem cell lineages. In the one-cell
embryo, a contractile cortical actomyosin network contributes to asymmetric division by segregating ...partitioning-defective (PAR) proteins to discrete cortical domains. In the current study, we found that the plasma membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP
) localizes to polarized dynamic structures in
zygotes, distributing in a PAR-dependent manner along the anterior-posterior (A-P) embryonic axis. PIP
cortical structures overlap with F-actin, and coincide with the actin regulators RHO-1 and CDC-42, as well as ECT-2. Particle image velocimetry analysis revealed that PIP
and F-actin cortical movements are coupled, with PIP
structures moving slightly ahead of F-actin. Importantly, we established that PIP
cortical structure formation and movement is actin dependent. Moreover, we found that decreasing or increasing the level of PIP
resulted in severe F-actin disorganization, revealing interdependence between these components. Furthermore, we determined that PIP
and F-actin regulate the sizing of PAR cortical domains, including during the maintenance phase of polarization. Overall, our work establishes that a lipid membrane component, PIP
, modulates actin organization and cell polarity in
embryos.
Asymmetric division is crucial for embryonic development and stem cell lineages. In the one-cell Caenorhabditis elegans embryo, a contractile cortical actomyosin network contributes to asymmetric ...division by segregating partitioning-defective (PAR) proteins to discrete cortical domains. In the current study, we found that the plasma membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2) localizes to polarized dynamic structures in C. elegans zygotes, distributing in a PAR-dependent manner along the anterior–posterior (A–P) embryonic axis. PIP2 cortical structures overlap with F-actin, and coincide with the actin regulators RHO-1 and CDC-42, as well as ECT-2. Particle image velocimetry analysis revealed that PIP2 and F-actin cortical movements are coupled, with PIP2 structures moving slightly ahead of F-actin. Importantly, we established that PIP2 cortical structure formation and movement is actin dependent. Moreover, we found that decreasing or increasing the level of PIP2 resulted in severe F-actin disorganization, revealing interdependence between these components. Furthermore, we determined that PIP2 and F-actin regulate the sizing of PAR cortical domains, including during the maintenance phase of polarization. Overall, our work establishes that a lipid membrane component, PIP2, modulates actin organization and cell polarity in C. elegans embryos.Highlighted Article: PI(4,5)P2 is distributed in dynamic cortical structures and regulates asymmetric division by controlling actin organization as well as cell polarity in the one-cell C. elegans embryo.
PDF
