Evaluation of MRI-only based online adaptive radiotherapy of abdominal region on MR-linac

Purpose A hybrid magnetic resonance linear accelerator (MRL) can perform magnetic resonance imaging (MRI) with high soft-tissue contrast to be used for online adaptive radiotherapy (oART). To obtain electron densities needed for the oART dose calculation, a computed tomography (CT) is often deformably registered to MRI. Our aim was to evaluate an MRI-only based synthetic CT (sCT) generation as an alternative to the deformed CT (dCT)-based oART in the abdominal region. Methods The study data consisted of 57 patients who were treated on a 0.35 T MRL system mainly for abdominal tumors. Simulation MRI-CT pairs of 43 patients were used for training and validation of a prototype convolutional neural network sCT-generation algorithm, based on HighRes3DNet, for the abdominal region. For remaining test patients, sCT images were produced from simulation MRIs and daily MRIs. The dCT-based plans were re-calculated on sCT with identical calculation parameters. The sCT and dCT were compared in terms of geometric agreement and calculated dose. Results The mean and one standard deviation of the geometric agreement metrics over dCT-sCT-pairs were: mean error of 8 +/- 10 HU, mean absolute error of 49 +/- 10 HU, and Dice similarity coefficient of 55 +/- 12%, 60 +/- 5%, and 82 +/- 15% for bone, fat, and lung tissues, respectively. The dose differences between the sCT and dCT-based dose for planning target volumes were 0.5 +/- 0.9%, 0.6 +/- 0.8%, and 0.5 +/- 0.8% at D-2%, D-50%, and D-98% in physical dose and 0.8 +/- 1.4%, 0.8 +/- 1.2%, and 0.6 +/- 1.1% in biologically effective dose (BED). For organs-at-risk, the dose differences of all evaluated dose-volume histogram points were within [-4.5%, 7.8%] and [-1.1 Gy, 3.5 Gy] in both physical dose and BED. Conclusions The geometric agreement metrics were within typically reported values and most average relative dose differences were within 1%. Thus, an MRI-only sCT-based approach is a promising alternative to the current clinical practice of the abdominal oART on MRL.Peer reviewe

Dehydrogenase-dependent ethanol metabolism in deer mice (Peromyscus maniculatus) lacking cytosolic alcohol dehydrogenase. Reversibility and isotope effects in vivo and in subcellular fractions

Elimination of [2H]ethanol in vivo as studied by gas chromatography/mass spectrometry occurred at about half the rate in deer mice reported to lack alcohol dehydrogenase (ADH-) compared with ADH+ deer mice and exhibited kinetic isotope effects on Vmax and Km (D(V/K] of 2.2 +/- 0.1 and 3.2 +/- 0.8 in the two strains, respectively. To an equal extent in both strains, ethanol elimination was accompanied by an ethanol-acetaldehyde exchange with an intermolecular transfer of hydrogen atoms, indicating the occurrence of dehydrogenase activity. This exchange was also observed in perfused deer mouse livers. Based on calculations it was estimated that at least 50% of ethanol elimination in ADH- deer mice was caused by the action of dehydrogenase systems. NADPH-supported cytochrome P-450-dependent ethanol oxidation in liver microsomes from ADH+ and ADH- deer mice was not stereoselective and occurred with a D(V/K) of 3.6. The D(V/K) value of catalase-dependent oxidation was 1.8, whereas a kinetic isotope effect of cytosolic ADH in the ADH+ strain was 3.2. Mitochondria from both ADH+ and ADH- deer mice catalyzed NAD+-dependent ethanol oxidation and NADH-dependent acetaldehyde reduction. The kinetic isotope effects of NAD+-dependent ethanol oxidation in the mitochondrial fraction from ADH+ and ADH- deer mice were 2.0 +/- 0.1 and 2.3 +/- 0.3, respectively. The results indicate only a minor contribution by cytochrome P-450 to ethanol elimination, whereas the isotope effects are consistent with ethanol oxidation by the catalase-H2O2 system in ADH- deer mice in addition to the dehydrogenase systems

Managing Soybean Insects

36 pp., 3 tables, 18 illustrations, 28 photosThis publication details integrated pest management principles for managing soybean insects. Topics include variety selection, inspecting fields for insects and damage, soybean insect pests, and insecticide application methods. A table lists products registered for controlling soybean insects

Сенсибилизация к аллергенам клещей домашней пыли у детей

ДЫХАТЕЛЬНАЯ ГИПЕРЧУВСТВИТЕЛЬНОСТЬАЛЛЕРГОЗЫ РЕСПИРАТОРНЫЕГИПЕРСЕНСИБИЛИЗАЦИЯ РЕСПИРАТОРНАЯРЕСПИРАТОРНАЯ АЛЛЕРГИЯАЛЛЕРГЕНЫКЛЕЩИ ПЫЛЕВЫЕ ДОМАШНИЕDERMATOPHAGOIDES PTERONYSSINUSDERMATOPHAGOIDES FARINAEСЕНСИБИЛИЗАЦИЯ БИОЛОГИЧЕСКАЯСЕНСИБИЛИЗАЦИЯ К АЛЛЕРГЕНАМДЕТИОБЗОР ЛИТЕРАТУРЫАллергические заболевания представляют серьезную проблему современной медицины. Сенсибилизация к ингаляционным аллергенам является одним из ключевых факторов формирования респираторных аллергозов. Среди аэроаллергенов важное значение играют аллергенные компоненты домашней пыли – клещи Dermatophagoides pteronyssinus и Dermatophagoides farinae, составляющие до 90% акарофауны жилых помещений. В формировании сенсибилизации к клещам домашней пыли также предполагается роль индивидуальных источников аллергенов. Сенсибилизация к мажорным компонентам аллергена клещей домашней пыли ассоциируется с риском развития бронхиальной астмы, к минорным (Der p 10) – риском развития перекрестных реакций с тропомиозином других беспозвоночных, тропомиозином человека. Аллергены клещей домашней пыли (Der p 2 и Der f 2) могут быть ответственны за симптомы оральной клещевой анафилаксии, а также способствовать развитию сенсибилизации к бактериальным антигенам Staphylococcus aureus и Escherichia coli. В 1 части статьи изложены биология и источники клеща домашней пыли. Представлена классификация аллергенов, пути сенсибилизации и распространенность сенсибилизации к клещу домашней пыли у детей.Allergic diseases are a serious problem in modern medicine. Sensitization to inhalation allergens is one of the key factors in the formation of respiratory allergoses. Among aeroallergens, allergenic components of domestic dust play an important role – mites Dermatophagoides pteronyssinus and Dermatophagoides farinae, that make up to 90% of the acarofauna of residential premises. In the formation of sensitization to domestic dust mites, the role of individual sources of allergens is also considered. Sensitization to the major components of the domestic dust mite allergens is associated with the risk of developing bronchial asthma, to minor ones (Der p 10) – the risk of cross-reactions with tropomyosin of other invertebrates, human tropomyosin. Domestic dust mite allergens (Der p 2 and Der f 2) may be responsible for the symptoms of oral tick-born anaphylaxis as well as for the development of sensitization to bacterial antigens of Staphylococcus aureus and Escherichia coli. Part 1 of this article outlines biology and sources of the domestic dust mite. The classification of allergens, sensitization pathways and the prevalence of sensitization to domestic dust mite in children are presented