Dosimetric comparison of M6 CyberKnife plans optimized with Precision and RayStation 12A treatment planning systems.

Purpose: Treatment planning for CyberKnife (CK) (Accuray, USA) can be performed with Precision (Accuray, USA) or RayStation (RS) (RaySearch Laboratories, Sweden) treatment planning systems (TPS). RaySearch recently released a new version of the CK module in RS 12A. The objective of the study was to compare plan quality between RS 12A and Precision.

Is the protactinium(V) mono-oxo bond weaker than what we thought?

The bond distance is the simplest and most obvious indicator of the nature of a given chemical bond. However, for rare chemistry, it may happen that it is not yet firmly established. In this communication, we will show that the formally-triple protactinium(V) mono-oxo bond is predicted to be longer than what was previously reported in the solid state and in solution, based on robust quantum mechanical calculations, supported by an extensive methodological study.

Toward a realistic theoretical electronic spectra of metal aqua ions in solution: The case of Ce(H2O)n3+ using statistical methods and quantum chemistry calculations.

Accurately predicting spectra for heavy elements, often open-shell systems, is a significant challenge typically addressed using a single cluster approach with a fixed coordination number. Developing a realistic model that accounts for temperature effects, variable coordination numbers, and interprets experimental data is even more demanding due to the strong solute-solvent interactions present in solutions of heavy metal cations. This study addresses these challenges by combining multiple methodologies to accurately predict realistic spectra for highly charged metal cations in aqueous media, with a focus on the electronic absorption spectrum of Ce3+ in water.

Experimental and Theoretical Study of the Reaction of F with Thiirane.

The kinetics of the F reaction with thiirane (CHS) was studied for the first time in a flow reactor combined with mass spectrometry at a total helium pressure of 2 Torr and in the temperature range of 220 to 800 K. The rate constant of the title reaction was determined under pseudo-first-order conditions, either monitoring the kinetics of F or CHS consumption in excess of thiirane or of F, respectively: = (5.79 ± 0.

Refining Treatment Planning in STereotactic Arrhythmia Radioablation: Benchmark Results and Consensus Statement From the STOPSTORM.eu Consortium.

Purpose: STereotactic Arrhythmia Radioablation (STAR) showed promising results in patients with refractory ventricular tachycardia. However, clinical data are scarce and heterogeneous. The STOPSTORM.

Spatial Distribution of Recurrence and Long-Term Toxicity Following Dose Escalation to the Dominant Intra-Prostatic Nodule for Intermediate-High-Risk Prostate Cancer: Insights from a Phase I/II Study.

We investigated spatial patterns between primary and recurrent tumor sites and assessed long-term toxicity after dose escalation stereotactic body radiation therapy (SBRT) to the dominant intra-prostatic nodule (DIN). In 33 patients with intermediate-high-risk prostate cancer (PCa), doses up to 50 Gy were administered to the DIN. Recurrence sites were determined and compared to the original tumor development sites through multiparametric MRI and Ga-labeled prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (Ga-PSMA-PET/CT) images.

Assessment of the surface contamination of the primary packaging of oral antineoplastic drugs and secondary packaging of chemotherapy preparations at a Swiss hospital.

Introduction: Due to the high toxicity of antineoplastic drugs, handling their packaging could lead to the chemical contamination of hospital environments and exposure risks to healthcare professionals and patients. This study aimed to assess the contamination of two main surfaces: the outer primary packaging of oral antineoplastic drug formulations (  =  36) available on the Swiss market and the surface of secondary packaging of injectable antineoplastic drug preparations (  =  60) produced by the pharmacy of a Swiss hospital and carriers used for transport (  =  5).

Methods: Samples were collected using a validated wipe sampling method.

Long-Term Results of Stereotactic Radiotherapy in Patients with at Least 10 Brain Metastases at Diagnosis.

Purpose: to evaluate an SRT approach in patients with at least 10 lesions at the time of BM initial diagnosis.

Methods: This is a monocentric prospective cohort of patients treated by SRT, followed by a brain MRI every two months. Subsequent SRT could be delivered in cases of new BMs during follow-up.

Interoperable workflows by exchanging grid-based data between quantum-chemical program packages.

Quantum-chemical subsystem and embedding methods require complex workflows that may involve multiple quantum-chemical program packages. Moreover, such workflows require the exchange of voluminous data that go beyond simple quantities, such as molecular structures and energies. Here, we describe our approach for addressing this interoperability challenge by exchanging electron densities and embedding potentials as grid-based data.

Stability of the Protactinium(V) Mono-Oxo Cation Probed by First-Principle Calculations.

This study explores the distinctive behavior of protactinium (Z=91) within the actinide series. In contrast to neighboring elements like uranium or plutonium, protactinium in the pentavalent state diverges by not forming the typical dioxo protactinyl moiety PaO in aqueous phase. Instead, it manifests as a monooxo PaO cation or a Pa .

Early Steps in the O Scavenger Process in the Aqueous Phase: Hydrazine vs DEHA.

We investigate the first direct proton abstraction reactions from reducing agents () hydrazine and diethyl hydroxylamine (DEHA), toward dioxygen (O) in the aqueous phase, spanning ambient to high-temperature conditions. Quantum chemistry methods and molecular dynamics simulations are employed in this study. Quantum chemistry methods are used to analyze the quasi-equilibrium between a reactive conformation and a transition state in the [,O] cluster.

Excited states of polonium(IV): electron correlation and spin-orbit coupling in the Po free ion and in the bare and solvated [PoCl] and [PoCl] complexes.

Polonium (Po, = 84) is a main-block element with poorly known physico-chemical properties. Not much information has been firmly acquired since its discovery by Marie and Pierre Curie in 1898, especially regarding its speciation in aqueous solution and spectroscopy. In this work, we revisit the absorption properties of two complexes, [PoCl] and [PoCl], using quantum mechanical calculations.

The hydration of an oxy-polycyclic aromatic compound: the case of naphthaldehyde.

The study of the intermolecular interactions of polycyclic aromatic compounds, considered as important pollutants of the Earth's atmosphere since they are emitted by the partial combustion of fuels, is essential to understand the formation and aging of their aerosols. In this study, the hydration of α-naphthaldehyde and β-naphthaldehyde isomers was investigated through a combination of Fourier transform microwave spectroscopy and quantum chemical calculations. Monohydrate structures were observed experimentally for both isomers, with two hydrate structures observed for β-naphthaldehyde and only one for α-naphthaldehyde, consistent with computational predictions.

3D-conformal very-high energy electron therapy as candidate modality for FLASH-RT: A treatment planning study for glioblastoma and lung cancer.

Background: Pre-clinical ultra-high dose rate (UHDR) electron irradiations on time scales of 100 ms have demonstrated a remarkable sparing of brain and lung tissues while retaining tumor efficacy when compared to conventional dose rate irradiations. While clinically-used gantries and intensity modulation techniques are too slow to match such time scales, novel very-high energy electron (VHEE, 50-250 MeV) radiotherapy (RT) devices using 3D-conformed broad VHEE beams are designed to deliver UHDR treatments that fulfill these timing requirements.

Purpose: To assess the dosimetric plan quality obtained using VHEE-based 3D-conformal RT (3D-CRT) for treatments of glioblastoma and lung cancer patients and compare the resulting treatment plans to those delivered by standard-of-care intensity modulated photon RT (IMRT) techniques.

Protein-ligand interactions from a quantum fragmentation perspective: The case of the SARS-CoV-2 main protease interacting with α-ketoamide inhibitors.

We present a hybrid, multi-method, computational scheme for protein/ligand systems well suited to be used on modern and forthcoming massively parallel computing systems. The scheme relies on a multi-scale polarizable molecular modeling, approach to perform molecular dynamics simulations, and on an efficient Density Functional Theory (DFT) linear scaling method to post-process simulation snapshots. We use this scheme to investigate recent α-ketoamide inhibitors targeting the main protease of the SARS-CoV-2 virus.

Coordination and thermodynamic properties of aqueous protactinium(V) by first-principle calculations.

Protactinium ( = 91) is a very rare actinide with peculiar physico-chemical properties. Indeed, although one may naively think that it behaves similarly to either thorium or uranium by its position in the periodic table, it may in fact follow its own rules. Because of the quite small energy gap between its valence shells (in particular the 5f and 6d ones) and also the strong influence of relativistic effects on its properties, it is actually a challenging element for theoretical chemists.

Uranium(iv) alkyl cations: synthesis, structures, comparison with thorium(iv) analogues, and the influence of arene-coordination on thermal stability and ethylene polymerization activity.

Reaction of [(XA)U(CHSiMe)] (1; XA = 4,5-bis(2,6-diisopropylanilido)-2,7-di--butyl-9,9-dimethylxanthene) with 1 equivalent of [PhC][B(CF)] in arene solvents afforded the arene-coordinated uranium alkyl cations, [(XA)U(CHSiMe)(η -arene)][B(CF)] {arene = benzene (2), toluene (3), bromobenzene (4) and fluorobenzene (5)}. Compounds 2, 3, and 5 were crystallographically characterized, and in all cases the arene is π-coordinated. Solution NMR studies of 2-5 suggest that the binding preferences of the [(XA)U(CHSiMe)] cation follow the order: toluene ≈ benzene > bromobenzene > fluorobenzene.

Geometries, interaction energies and bonding in [Po(HO)] and [PoCl] complexes.

Polonium ( = 84) is one of the rarest elements on Earth. More than a century after its discovery, its chemistry remains poorly known and even basic questions have not yet been satisfactorily addressed. In this work, we perform a systematic study of the geometries, interactions energies and bonding in basic polonium(IV) species, namely the hydrated [Po(HO)] and chlorinated [PoCl] complexes by means of gas-phase electronic structure calculations.

Frozen-Density Embedding for Including Environmental Effects in the Dirac-Kohn-Sham Theory: An Implementation Based on Density Fitting and Prototyping Techniques.

Frozen density embedding (FDE) represents an embedding scheme in which environmental effects are included from first-principles calculations by considering the surrounding system explicitly by means of its electron density. In the present paper, we extend the full four-component relativistic Dirac-Kohn-Sham (DKS) method, as implemented in the BERTHA code, to include environmental and confinement effects with the FDE scheme (DKS-in-DFT FDE). The implementation, based on the auxiliary density fitting techniques, has been enormously facilitated by BERTHA's python API (PyBERTHA), which facilitates the interoperability with other FDE implementations available through the PyADF framework.

Commissioning and validation of RayStation treatment planning system for CyberKnife M6.

Background: RaySearch (AB, Stockholm) has released a module for CyberKnife (CK) planning within its RayStation (RS) treatment planning system (TPS).

Purpose: To create and validate beam models of fixed, Iris, and multileaf collimators (MLC) of the CK M6 for Monte Carlo (MC) and collapsed cone (CC) algorithms in the RS TPS.

Methods: Measurements needed for the creation of the beam models were performed in a water tank with a stereotactic PTW 60018 diode.

COVID salivary diagnostics: A comparative technical study.

Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, molecular diagnostics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have taken center stage in the detection of infected individuals for isolation purposes but also in the mass surveillance as a preventive strategy to contain the virus spread. While nasopharyngeal swabs (NPS) have remained the golden standard substrate, salivary diagnostic for SARS-CoV-2 has been proposed as an alternative and noninvasive measure in vulnerable individuals. Nevertheless, there is a widespread assumption that salivary reverse-transcription polymerase chain reaction (RT-PCR) does not match the quality of testing using NPS and particular care should be taken in respect to food or beverage intake, when sampling saliva.