Joint EURADOS-EANM initiative for an advanced computational framework for the assessment of external dose rates from nuclear medicine patients.

Background: In order to ensure adequate radiation protection of critical groups such as staff, caregivers and the general public coming into proximity of nuclear medicine (NM) patients, it is necessary to consider the impact of the radiation emitted by the patients during their stay at the hospital or after leaving the hospital. Current risk assessments are based on ambient dose rate measurements in a single position at a specified distance from the patient and carried out at several time points after administration of the radiopharmaceutical to estimate the whole-body retention. The limitations of such an approach are addressed in this study by developing and validating a more advanced computational dosimetry approach using Monte Carlo (MC) simulations in combination with flexible and realistic computational phantoms and time activity distribution curves from reference biokinetic models.

Curcumin inhibits the invasion and migration of pancreatic cancer cells by upregulating TFPI-2 to regulate ERK- and JNK-mediated epithelial-mesenchymal transition.

Purpose: Pancreatic cancer (PC) is one of the most deadly human malignancies. Curcumin is a natural polyphenolic compound with wide-ranging pharmacological effects. Growing evidence suggests that curcumin has anticancer activity against PC, but the mechanism remains incompletely elucidated.

Modelling DTPA therapy following Am contamination in rats.

A major challenge in modelling the decorporation of actinides (An), such as americium (Am), with DTPA (diethylenetriaminepentaacetic acid) is the fact that standard biokinetic models become inadequate for assessing radionuclide intake and estimating the resulting dose, as DTPA perturbs the regular biokinetics of the radionuclide. At present, most attempts existing in the literature are empirical and developed mainly for the interpretation of one or a limited number of specific incorporation cases. Recently, several approaches have been presented with the aim of developing a generic model, one of which reported the unperturbed biokinetics of plutonium (Pu), the chelation process and the behaviour of the chelated compound An-DTPA with a single model structure.

Analysis of the Risk Factors of Breast Cancer-Related Lymphedema and Construction and Evaluation of a Prediction Model.

The occurrence of breast cancer-related lymphedema (BCRL) in postoperative breast cancer survivors is described and the independent risk factors of BCRL are analyzed. A BCRL nomogram prediction model is constructed, and its effectiveness is evaluated to screen out high-risk patients with BCRL. A univariate analysis was carried out to determine the risk factors possibly related to BCRL, and a logistic regression analysis was utilized to determine the independent risk factors related to BCRL.

Estimation of relative biological effectiveness of Ac compared to Lu during [Ac]Ac-PSMA and [Lu]Lu-PSMA radiopharmaceutical therapy using TOPAS/TOPAS-nBio/MEDRAS.

Aim: Over recent years, [Ac]Ac-PSMA and [Lu]Lu-PSMA radiopharmaceutical therapy have evolved as a promising treatment option for advanced prostate cancer. Especially for alpha particle emitter treatments, there is still a need for improving dosimetry, which requires accurate values of relative biological effectiveness (RBE). To achieve that, consideration of DNA damages in the cell nucleus and knowledge of the energy deposition in the location of the DNA at the nanometer scale are required.

Heterogeneity of absorbed dose distribution in kidney tissues and dose-response modelling of nephrotoxicity in radiopharmaceutical therapy with beta-particle emitters: A review.

Absorbed dose heterogeneity in kidney tissues is an important issue in radiopharmaceutical therapy. The effect of absorbed dose heterogeneity in nephrotoxicity is, however, not fully understood yet, which hampers the implementation of treatment optimization by obscuring the interpretation of clinical response data and the selection of optimal treatment options. Although some dosimetry methods have been developed for kidney dosimetry to the level of microscopic renal substructures, the clinical assessment of the microscopic distribution of radiopharmaceuticals in kidney tissues currently remains a challenge.

Internal radiation exposure from TENORM for workers conducting cleaning activities on equipment used at geothermal energy plant.

Geothermal energy is predicted to be one of the most important renewable energy sources in the near future. In geothermal energy plants, the secondary products such as the scale containing naturally occurring radioactive material (NORM) and adhering to the surface of equipment produce radiation fields. The workers who maintain and clean such equipment are at a risk to be exposed by the technically enhanced NORM (TENORM).

Heterogeneity of dose distribution in normal tissues in case of radiopharmaceutical therapy with alpha-emitting radionuclides.

Heterogeneity of dose distribution has been shown at different spatial scales in diagnostic nuclear medicine. In cancer treatment using new radiopharmaceuticals with alpha-particle emitters, it has shown an extensive degree of dose heterogeneity affecting both tumour control and toxicity of organs at risk. This review aims to provide an overview of generalized internal dosimetry in nuclear medicine and highlight the need of consideration of the dose heterogeneity within organs at risk.

Low-frequency repetitive transcranial magnetic stimulation to the right Broca mirror area for improving auditory comprehension in a sensory aphasia after stroke: a case report.

Aphasia is a common consequence of stroke and repetitive transcranial magnetic stimulation (rTMS) may be a promising brain stimulation technique in the treatment of aphasia. However, there are few reports about the therapeutic effect of rTMS for Broca's area in patients with sensory aphasia. This study reported one stroke patient with sensory aphasia who received 6 treatment sessions of low-frequency rTMS before speech and language therapy.

Radical recombination and antioxidants: a hypothesis on the FLASH effect mechanism.

Purpose: FLASH (ultra-high dose rate) radiotherapy spares normal tissue while keeping tumor control. However, the mechanism of the FLASH effect remains unclear and may have consequences beyond the irradiated area.

Materials And Methods: We reanalyze the available results of ultra-high-dose-rate-related experiments to find out the key points of the mechanism of the FLASH effect.

Long non‑coding RNA 01614 hyperactivates WNT/β‑catenin signaling to promote pancreatic cancer progression by suppressing GSK‑3β.

Pancreatic cancer (PC) is a lethal type of cancer for which effective therapies are limited. Long non‑coding RNAs (lncRNAs) represent a critical type of regulator category, mediating the tumorigenesis and development of various tumor types, including PC. However, the expression patterns and functions of numerous lncRNAs in PC remain poorly understood.

An encoder-decoder network for direct image reconstruction on sinograms of a long axial field of view PET.

Purpose: Deep learning is an emerging reconstruction method for positron emission tomography (PET), which can tackle complex PET corrections in an integrated procedure. This paper optimizes the direct PET reconstruction from sinogram on a long axial field of view (LAFOV) PET.

Methods: This paper proposes a novel deep learning architecture to reduce the biases during direct reconstruction from sinograms to images.

Correlation between focal lesion sites and language deficits in the acute phase of post-stroke aphasia.

Introduction: Focal lesion sites can predict the language function of patients with aphasia during the subacute or chronic phases. However, the relationship between focal lesion sites and language deficits in the acute phase remains unclear. Therefore, our study aimed to investigate the relationship between focal lesion sites and fluency, auditory comprehension, repetition and naming deficits in patients with acute aphasia to further understand the pathophysiological mechanism of aphasia.

Application of High-Z Gold Nanoparticles in Targeted Cancer Radiotherapy-Pharmacokinetic Modeling, Monte Carlo Simulation and Radiobiological Effect Modeling.

High-Z gold nanoparticles (AuNPs) conjugated to a targeting antibody can help to improve tumor control in radiotherapy while simultaneously minimizing radiotoxicity to adjacent healthy tissue. This paper summarizes the main findings of a joint research program which applied AuNP-conjugates in preclinical modeling of radiotherapy at the Klinikum rechts der Isar, Technical University of Munich and Helmholtz Zentrum München. A pharmacokinetic model of superparamagnetic iron oxide nanoparticles was developed in preparation for a model simulating the uptake and distribution of AuNPs in mice.

A Computational Model for Oxygen Depletion Hypothesis in FLASH Effect.

Experiments have reported low normal tissue toxicities during FLASH irradiation, but the mechanism has not been elaborated. Several hypotheses have been proposed to explain the mechanism. One hypothesis is oxygen depletion.

Development of Chinese mesh-type pediatric reference phantom series and application in dose assessment of Chinese undergoing computed tomography scanning.

Pediatric patients are in a growing stage with more dividing cells than adults. Therefore, they are more sensitive to the radiation dose when undergoing computed tomography (CT) scanning. It is necessary and essential to assess the organ absorbed dose and effective dose to children.

Radiopharmacokinetic modelling and radiation dose assessment of Ra used for treatment of metastatic castration-resistant prostate cancer.

Purpose: Ra-223 dichloride (Ra, Xofigo®) is used for treatment of patients suffering from castration-resistant metastatic prostate cancer. The objective of this work was to apply the most recent biokinetic model for radium and its progeny to show their radiopharmacokinetic behaviour. Organ absorbed doses after intravenous injection of Ra were estimated and compared to clinical data and data of an earlier modelling study.

Multi-scale Monte Carlo simulations of gold nanoparticle-induced DNA damages for kilovoltage X-ray irradiation in a xenograft mouse model using TOPAS-nBio.

Background: Gold nanoparticles (AuNPs) are considered as promising agents to increase the radiosensitivity of tumor cells. However, the biological mechanisms of radiation enhancement effects of AuNPs are still not well understood. We present a multi-scale Monte Carlo simulation framework within TOPAS-nBio to investigate the increase of DNA damage due to the presence of AuNPs in mouse tumor models.

Uncertainty analysis in internal dose calculations for cerium considering the uncertainties of biokinetic parameters and S values.

Radioactive cerium and other lanthanides can be transported through the aquatic system into foodstuffs and then be incorporated by humans. Information on the uncertainty of reported dose coefficients for exposed members of the public is then needed for risk analysis. In this study, uncertainties of dose coefficients due to the ingestion of the radionuclides Ce and Ce were estimated.

A New Pharmacokinetic Model Describing the Biodistribution of Intravenously and Intratumorally Administered Superparamagnetic Iron Oxide Nanoparticles (SPIONs) in a GL261 Xenograft Glioblastoma Model.

Background: Superparamagnetic iron oxide nanoparticles (SPIONs) have displayed multifunctional applications in cancer theranostics following systemic delivery. In an effort to increase the therapeutic potential of local therapies (including focal hyperthermia), nanoparticles can also be administered intratumorally. Therefore, the development of a reliable pharmacokinetic model for the prediction of nanoparticle distribution for both clinically relevant routes of delivery is of high importance.

Oleanane- and Ursane-Type Triterpene Saponins from Exhibit Neuroprotective Effects.

Six new pentacyclic triterpenoid saponins, centelloside F (), centelloside G (), 11--asiaticoside B (), 11--madecassoside (), 11(β)-methoxy asiaticoside B (), and 11(β)-methoxy madecassoside (), along with seven known ones, asiaticoside (), asiaticoside B (), madecassoside (), centellasaponin A (), isoasiaticoside (), scheffoleoside A (), and centelloside E (), were separated from the 80% MeOH extract of the whole plant of , which has been used as a medicinal plant and is now commercially available as a diatery supplement in many countries. Compounds and , and , and and are three pairs of isomers with oleanane- or ursane-type triterpenes as aglycones. The chemical structures of the new triterpene saponins were fully characterized by extensive analysis of their nuclear magnetic resonance and high-resolution electrospray ionization mass spectrometry data.

Internal microdosimetry of alpha-emitting radionuclides.

At the tissue level, energy deposition in cells is determined by the microdistribution of alpha-emitting radionuclides in relation to sensitive target cells. Furthermore, the highly localized energy deposition of alpha particle tracks and the limited range of alpha particles in tissue produce a highly inhomogeneous energy deposition in traversed cell nuclei. Thus, energy deposition in cell nuclei in a given tissue is characterized by the probability of alpha particle hits and, in the case of a hit, by the energy deposited there.

Measurement, model prediction and uncertainty quantification of plasma clearance of cerium citrate in humans.

Double tracer studies in healthy human volunteers with stable isotopes of cerium citrate were performed with the aim of investigating the gastro-intestinal absorption of cerium (Ce), its plasma clearance and urinary excretion. In the present work, results of the clearance of Ce in blood plasma are shown after simultaneous intravenous and oral administration of a Ce tracer. Inductively coupled plasma mass spectrometry was used to determine the tracer concentrations in plasma.

Determining dose enhancement factors of high-Z nanoparticles from simulations where lateral secondary particle disequilibrium exists.

Nanoparticles (NPs) containing high atomic number (high-Z) materials have been shown to enhance the radiobiological effectiveness of ionizing radiation. This effect is often attributed to an enhancement of the absorbed dose in the vicinity of the NPs, based on Monte Carlo simulations that show a significant local enhancement of the energy deposition on the microscopic scale. The results of such simulations may be significantly biased and lead to a severe overestimation of the dose enhancement if the condition of secondary particle equilibrium is not met in the simulation setup.

The effect of attenuation map, scatter energy window width, and volume of interest on the calibration factor calculation in quantitative Lu SPECT imaging: Simulation and phantom study.

Purpose: The objective of this study was to evaluate the image degrading factors in quantitative Lu SPECT imaging when using both main gamma photopeak energies.

Methods: Phantom measurements with two different vials containing various calibrated activities in air or water were performed to derive a mean calibration factor (CF) for large and small volumes of interest (VOIs). In addition, Monte Carlo simulations were utilized to investigate the effect of scatter energy window width, scatter correction method, such as effective scatter source estimation (ESSE) and triple energy window (TEW), and attenuation map on the quantification of Lu.