Impact of contrast-enhanced CT in the dosimetry of SBRT for liver metastases treated with MR-Linac.

BACKGROUND: To investigate the impact of using contrast-enhanced computed tomography (CHCT) in the dosimetry of stereotactic body radiation therapy (SBRT) for liver metastases treated with MR-Linac. METHODS: A retrospective study was conducted on 21 liver cancer patients treated with SBRT (50 Gy in 5 fractions) using a 1.5 Tesla Unity MR-Linac. The clinical treatment plans optimised on plain computed tomography (pCT) were used as reference. The electronic density (ED) of regions of interest (ROIs) including the liver, duodenum, esophagus, spinal cord, heart, ribs, and lungs, from pCT and CHCT, was analysed. The average ED of each ROI from CHCT was used to generate synthetic CT (sCT) images by assigning the average ED value from the CHCT to the pCT. Clinical plans were recalculated on sCT images. Dosimetric comparisons between the original treatment plan (TPpCT) and the sCT plan (TPsCT) were performed using dose-volume histogram (DVH) parameters, and gamma analysis. RESULTS: Significant ED differences (p < 0.05) were observed in the liver, great vessels, heart, lungs, and spinal cord between CHCT and pCT, with the lungs showing the largest differences (average deviation of 11.73% and 12.15% for the left and right lung, respectively). The target volume covered by the prescribed dose (VDpre), and the dose received by 2% and 98% of the volume (D2%, and D98%, respectively) showed statistical differences (p < 0.05), while the gradient index (GI) and the conformity index (CI) did not. Average deviations in target volume dosimetric parameters were below 1.02%, with a maximum deviation of 5.57% for. For the organs at risk (OARs), significant differences (p < 0.05) were observed for D0.35cc and D1.2cc of the spinal cord, D10cc for the stomach, D0.5cc for the heart, and D30% for the liver-GTV, with mean deviations lower than 1.83% for all the above OARs. Gamma analysis using 2%-2 mm criteria yielded a median value of 95.64% (range 82.22-99.65%) for the target volume and 99.40% (range 58-100%) for the OARs. CONCLUSION: The findings suggest that the use of CHCT in the SBRT workflow for liver metastases may result in minor target volume overdosage, indicating its potential for adoption in clinical settings. However, its use should be further explored in a broader context and tied to personalized treatment approaches.

The impact of time to evacuation on outcomes in endoscopic surgery for supratentorial spontaneous intracerebral hemorrhage: a single-center retrospective study.

Supratentorial spontaneous intracerebral hemorrhage (SICH) can be treated with endoscopic surgery, but the optimal timing remains uncertain. We retrospectively analyzed data from 46 patients who underwent endoscopic surgery for supratentorial SICH. We examined the relationship between time to evacuation and functional outcome at 3 months, adjusting for prognostic factors. Surgical outcomes and complications were compared between patients with early (≤ 12 h) or late (> 12 h) evacuation. Median time to evacuation was 12 h, and the rate of unfavorable outcome (modified Rankin Scale > 3 at 3 months) was 32.6%. Longer time to evacuation was independently associated with unfavorable outcome (odds ratio per hour delay: 1.26). Late evacuation carried a 7.25-fold higher risk of unfavorable outcome compared to early evacuation. This association held across subgroups based on hematoma volume, location, and intraventricular extension (P for interaction > 0.05). Patients with late evacuation had fewer spot signs (24% vs. 4.8%, P = 0.035) and markers of hemorrhagic expansion (36% vs. 9.5%, P = 0.018), longer neurosurgical intensive care unit (NSICU) stay (3.2 vs. 1.9 days, P = 0.011) and hospital stay (15.7 vs. 11.9 days, P = 0.014), and higher 30-day mortality (28.6 vs. 4%, P = 0.036) and complication rates (57.1% vs. 28.0%, P = 0.023). This study suggests a potential association between early endoscopic evacuation of supratentorial SICH and improved functional outcomes, lower 30-day mortality and reduced complications. The need for timely intervention in managing supratentorial SICH is highlighted, yet further validation through multi-center prospective studies is essential to substantiate these findings and provide a higher level of evidence.

Endoport Assisted Endoscopic Surgery for Hypertensive Basal Ganglia Hemorrhage by Transsylvian Approach: Technical Nuances and Preliminary Clinical Results.

BACKGROUND: There is no clear evidence on the indication and surgical approaches on evacuating basal ganglia hemorrhage caused by hypertensive bleeding. Some studies have shown that minimally invasive approaches have therapeutic potentials, but its benefits remain inconclusive. We describe an endoport assisted endoscopic transsylvian approach for basal ganglia hemorrhage evacuation. We evaluate the safety and efficacy of this approach in a cohort study. METHODS: We included 19 patients (mean age 57 years) who underwent the surgery at a single county-level hospital in Yunan Province, China. The majority had a Glasgow coma scale between 9 and 12 on admission. The midline shift ranged from 16-29 mm (mean 19 mm). Hematoma volume ranged from 46 to 106 ml (mean 67 ml). Six patients (31.6%) presented with intraventricular hemorrhage. RESULTS: All patients achieved greater than 90% decrease in hematoma volume at postoperative computed tomography scan. The average operative time was 115 minutes and average blood loss of 44 ml. The most common postoperative complication was pulmonary infection (63.2%). No rebleeding, seizure, infectious meningitis, or postoperative mortality was observed. A total of 17 patients (89.5%) achieved good functional recovery at follow up within 90 days after surgery (Glasgow outcome scale 4-5) and 2 patients had severe disability (Glasgow outcome scale 3). CONCLUSIONS: Endoport assisted endoscopic surgery through transsylvian approach is safe and effective treatment for hypertensive basal ganglia hemorrhage. The majority of patients have good functional recovery and the rate of severe complications is low.

Noninvasively Modifying Band Structures of Wide-Bandgap Metal Oxides to Boost Photocatalytic Activity.

Although doping with appropriate heteroatoms is a powerful way of increasing visible light absorption of wide-bandgap metal oxide photocatalysts, the incorporation of heteroatoms into the photocatalysts usually leads to the increase of deleterious recombination centers of photogenerated charge carriers. Here, a conceptual strategy of increasing visible light absorption without causing additional recombination centers by constructing an ultrathin insulating heterolayer of amorphous boron oxynitride on wide-bandgap photocatalysts is shown. The nature of this strategy is that the active composition nitrogen in the heterolayer can noninvasively modify the electronic structure of metal oxides for visible light absorption through the interface contact between the heterolayer and metal oxides. The photocatalysts developed show significant improvements in photocatalytic activity under both UV-vis and visible light irradiation compared to the doped counterparts by conventional doping process. These results may provide opportunities for flexibly tailoring the electronic structure of metal oxides.

Dirac Node Lines in Pure Alkali Earth Metals.

Beryllium is a simple alkali earth metal, but has been the target of intensive studies for decades because of its unusual electron behavior at surfaces. The puzzling aspects include (i) severe deviations from the description of the nearly free-electron picture, (ii) an anomalously large electron-phonon coupling effect, and (iii) giant Friedel oscillations. The underlying origins for such anomalous surface electron behavior have been under active debate, but with no consensus. Here, by means of first-principles calculations, we discover that this pure metal system, surprisingly, harbors the Dirac node line (DNL) that in turn helps to rationalize many of the existing puzzles. The DNL is featured by a closed line consisting of linear band crossings, and its induced topological surface band agrees well with previous photoemission spectroscopy observations on the Be (0001) surface. We further reveal that each of the elemental alkali earth metals of Mg, Ca, and Sr also harbors the DNL and speculate that the fascinating topological property of the DNL might naturally exist in other elemental metals as well.