Quantitative Evaluation of Scintillation Camera Imaging Characteristics of Isotopes Used in Liver Radioembolization

Scintillation camera imaging is used for treatment planning and post-treatment dosimetry in liver radioembolization (RE). In yttrium-90 (90Y) RE, scintigraphic images of technetium-99m (99mTc) are used for treatment planning, while 90Y Bremsstrahlung images are used for post-treatment dosimetry. In holmium-166 (166Ho) RE, scintigraphic images of 166Ho can be used for both treatment planning and post-treatment dosimetry. The aim of this study is to quantitatively evaluate and compare the imaging characteristics of these three isotopes, in order that imaging protocols can be optimized and RE studies with varying isotopes can be compared.Phantom experiments were performed in line with NEMA guidelines to assess the spatial resolution, sensitivity, count rate linearity, and contrast recovery of 99mTc, 90Y and 166Ho. In addition, Monte Carlo simulations were performed to obtain detailed information about the history of detected photons. The results showed that the use of a broad energy window and the high-energy collimator gave optimal combination of sensitivity, spatial resolution, and primary photon fraction for 90Y Bremsstrahlung imaging, although differences with the medium-energy collimator were small. For 166Ho, the high-energy collimator also slightly outperformed the medium-energy collimator. In comparison with 99mTc, the image quality of both 90Y and 166Ho is degraded by a lower spatial resolution, a lower sensitivity, and larger scatter and collimator penetration fractions.The quantitative evaluation of the scintillation camera characteristics presented in this study helps to optimize acquisition parameters and supports future analysis of clinical comparisons between RE studies

Intravenous lidocaine infusions for 48 hours in open colorectal surgery: A prospective, randomized, double-blinded, placebo-controlled trial

Background: Although intravenous (i.v.) lidocaine is used as a perioperative analgesic in abdominal surgery, evidence of efficacy is limited. The infusion dose and duration remain unclear. This study aimed to investigate the effect of a longer low-dose 48-hour infusion regimen on these outcomes. Methods: Fifty-eight adults undergoing elective open colorectal surgery were randomized into the lidocaine group (1.5 mg/kg bolus followed by 1 mg/kg/h infusion for 48 hours) and control group. After surgery, patients were given a fentanyl patient-controlled analgesia machine and time to first bowel movement (primary outcome) and flatus were recorded. Postoperative pain scores and fentanyl consumption were assessed for 72 hours. Results: There was no significant difference in time to first bowel movement (80.1 ± 42.2 vs. 82.5 ± 40.4 hours; P = 0.830), time to first flatus (64.7 ± 38.5 vs. 70.0 ± 31.2 hours; P = 0.568), length of hospital stay (9 [8–13] vs. 11 [9–14) days; P = 0.531], nor postoperative pain scores in the lidocaine vs. control groups. Cumulative opioid consumption was significantly lower in the lidocaine vs. the control group from 24 hours onwards. At 72 hours, cumulative opioid consumption (μg fentanyl) in the lidocaine group (1,570 [825–3,587]) was over 40% lower than in the placebo group (2,730 [1,778–5,327]; P = 0.039). Conclusions: A 48-hour low-dose i.v. lidocaine infusion does not significantly speed the return of bowel function in patients undergoing elective open colorectal surgery. It was associated with reduced postoperative opioid consumption, but not with earlier hospital discharge, or lower pain scores

Allopatric speciation in the desert: diversification of cichlids at their geographical and ecological range limit in Iran

Cichlids are textbook examples for rapid diversification and high species diversity. While in South America, several hundred and in Africa, more than 1500 species of cichlid fish have been described, only one single cichlid species, Iranocichla hormuzensis Coad 1982, was known from Iran, the easternmost range margin of the species-rich African cichlids (Cichlidae: Pseudocrenilabrinae). The aim of our paper was to assess the genetic and phenotypic diversity among populations of Iranocichla across most of its geographical range in Southern Iran. For this, we sequenced two mitochondrial genes and collected color observation of male nuptial coloration in different habitats. Besides conspicuous differences in male nuptial coloration, we found considerable genetic differentiation among Iranocichla populations pointing to the existence of at least two allopatric species, with no evidence of more than one species at one site. Diversification within Iranocichla started, based on our data, in the middle or late Pleistocene and was followed by further population differentiation and bottlenecks during isolation events in the last glacial maximum. Population dispersal leading to the population structure observed today most likely occurred in the course of the early Holocene sea-level rise