In silico estimation of polyethylene glycol coating effect on metallic NPs radio-sensitization in kilovoltage energy beams.

Purpose: Nanoparticles (NPs) as radiosensitizers present a promising strategy for enhancing radiotherapy effectiveness, but their potential is significantly influenced by the properties of their surface coating, which can impact treatment outcomes. Most Monte Carlo studies have focused on metallic NPs without considering the impact of coating layers on radiosensitization. In this study, we aim to assess both the physical and radiobiological effects of nanoparticle coatings in nanoparticle-based radiation therapy.

Induction of immunogenic cell death and enhancement of the radiation-induced immunogenicity by chrysin in melanoma cancer cells.

Chrysin is a natural flavonoid with anti-cancer effects. Despite its beneficial effects, little information is available regarding its immunogenic cell death (ICD) properties. In this work, we hypothesized that chrysin can potentiate radiotherapy(RT)-induced immunogenicity in melanoma cell line (B16-F10).

Radiosensitization with metallic nanoparticles under MeV proton beams: local dose enhancement.

In addition to specific dosimetric properties of protons, their higher biological effectiveness makes them superior to X-rays and gamma radiation, in radiation therapy. In recent years, enrichment of tumours with metallic nanoparticles as radiosensitizer agents has generated high interest, with several studies attempting to confirm the efficacy of nanoparticles in proton therapy. In the present study Geant4 Monte Carlo (MC) code was used to quantify the increased nanoscopic dose deposition of 50 nm metallic nanoparticles including gold, bismuth, iridium, and gadolinium in water upon exposure to 5, 25, and 50 MeV protons.

The effect of nanoparticle coating on biological, chemical and biophysical parameters influencing radiosensitization in nanoparticle-aided radiation therapy.

Nanoparticle-based composites have the potential to meet requirements for radiosensitization in both therapeutic and diagnostic applications. The radiosensitizing properties of nanoparticles could be reliant on the nature of their coating layer. Any gains in reduced toxicity and aggregation or improved delivery to tumor cells for coated nanoparticles must be weighed against the loss of dose enhancement.

Radiation-induced dormancy of intracerebral melanoma: endotoxin inflammation leads to both shortened tumor dormancy and long-term survival with localized senescence.

Radiation therapy (RT) treats approximately half of all cancers and most brain cancers. RT is variably effective at inducing a dormant tumor state i.e.

Nanoscopic biodosimetry using plasmid DNA in radiotherapy with metallic nanoparticles.

Nanoscopic lesions (complex damages), are the most lethal lesions for the cells. As nanoparticles have become increasingly popular in radiation therapy and the importance of analyzing nanoscopic dose enhancement has increased, a reliable tool for nanodosimetry has become indispensable. In this regard, the DNA plasmid is a widely used tool as a nanodosimetry probe in radiobiology and nano-radiosensitization studies.

Radiobiological modeling of acute esophagitis after radiation therapy of head, neck, and thorax tumors: The influence of chemo-radiation.

Aim: The aim of this study was to evaluate the performance of various radiobiological models in predicting the occurrence of acute esophagitis (AE) during radiation therapy (RT) of head, neck, and thoracic tumors with concurrent and sequential chemotherapy. According to recent studies, the probability of AE following RT by normal tissue complication probability models is predictable.

Materials And Methods: A total of 100 patients with nasopharynx, larynx, Hodgkin's lymphoma, spinal metastases, and oral cavity and lung tumors were included in the study.

The use of the normal tissue non-complication probability (NTCP0) methodology as a new alternative of assessing side-effects in brachytherapy treatments.

Background: The NTCP methodology evaluating side-effects (S-Es) was initially used in radiotherapy (RT), and later was extended to brachytherapy (BT). The NTCP0 methodology has been recently introduced in RT. Given the advantages, this methodology could replace NTCP.

Accelerated brachytherapy with the Xoft electronic source used in association with iodine, gold, bismuth, gadolinium, and hafnium nano-radioenhancers.

Purpose: The current study was designed to calculate the dose enhancement factor (DEF) of iodine (I), gold (Au), bismuth (Bi), gadolinium (Gd), and hafnium (Hf) nanoparticles (NP)s by Monte Carlo (MC) modeling of an electronic brachytherapy source in resection cavities of breast tumors.

Methods And Materials: The GEANT4 MC code was used for simulation of a phantom containing a water-filled balloon and a Xoft source (50 kVp) to irradiate the margins of a resected breast tumor. NPs with a diameter of 20 nm and concentrations from 1 to 5% w/w were simulated in a tumor margin with 5 mm thickness as well as a hypothetical breast model consisting of spherical island-like residual tumor-remnants.

The use of the normal tissue non-complication probability (NTCP0) in the safety evaluations as a new alternative of assessing the side-effects of the radiation oncology treatments.

Purpose: To encourage the use of the NTCP0 for evaluating safety as a new alternative of assessing the S-Es of the radiation oncology treatments; and the use of the 'NTCP0cal' methodology that calculates/estimates NTCP0.

Method: Revisions of studies related to use of the NTCP in the evaluations of S-Es. Development of the first version of the Matlab application of our methodology, which provides three options, two of them employ the well-known aspects of a phenomenological model, or the relationship with the TNTCP; where NTCP0 = 100%-TNTCP; and the third option determines NTCP0 from an assumed NTCP discrete probabilistic distribution from the binomial distribution, where one of its parameters is automatically defined from a databased of the Disease locations Vs.

Predicting the Risk of Radiation Pneumonitis and Pulmonary Function Changes after Breast Cancer Radiotherapy.

Background: Radiotherapy plays an important role in the treatment of breast cancer. In the process of radiotherapy, the underling lung tissue receives higher doses from treatment field, which led to incidence of radiation pneumonitis.

Objective: The present study aims to evaluate the predictive factors of radiation pneumonitis and related changes in pulmonary function after 3D-conformal radiotherapy of breast cancer.

Shielding characteristics of nanocomposites for protection against X- and gamma rays in medical applications: effect of particle size, photon energy and nano-particle concentration.

In recent decades, nanomaterials have been extensively investigated for many applications. Composites doped with different metal nanoparticles have been suggested as effective shielding materials to replace conventional lead-based materials. The use of concretes as structural and radiation protective material has been influenced by the addition of nanomaterials.

Design and fabrication of a Nano-based neutron shield for fast neutrons from medical linear accelerators in radiation therapy.

Background: Photo-neutrons are produced at the head of the medical linear accelerators (linac) by the interaction of high-energy photons, and patients receive a whole-body-absorbed dose from these neutrons. The current study aimed to find an efficient shielding material for fast neutrons.

Methods: Nanoparticles (NPs) of FeO and BC were applied in a matrix of silicone resin to design a proper shield against fast neutrons produced by the 18 MeV photon beam of a Varian 2100 C/D linac.

Proposals of models for new formulations of the current complication-free cure (P+) and uncomplicated tumor control probability (UTCP) concepts, and total normal tissue complication probability of late complications.

This study proposes phenomenological models for total normal tissue complication probability (TNTCP) and NTCP0. NTCP0 is a new acronym for reformulating the current complication-free cure (P+) and uncomplicated tumor control probability (UTCP) concepts, and TNTCP will reformulate the current NTCP involving multiple organs at risks. The current probabilistic concepts are incoherently formulated with mathematical operations of tumor control probability (TCP) and normal tissue complication probability (NTCP) that are associated with different stochastic processes and random variables.

and characteristics of doxorubicin-loaded cyclodextrine-based polyester modified gadolinium oxide nanoparticles: a versatile targeted theranostic system for tumour chemotherapy and molecular resonance imaging.

-Cyclodextrine-based polyester was coated on the surface of gadolinium oxide nanoparticles (NPs) and then functionalised with folic acid to produce an efficient pH-sensitive targeted theranostic system (GdO@PCD-FA) for doxorubicin delivery and magnetic resonance imaging (MRI). GdO@PCD-FA was fully characterised by FTIR, vibrating sample magnetometer, TGA, XRD, SEM and TEM analyses. The dissolution profile of DOX showed a pH sensitive release.

Influence of the size of nano- and microparticles and photon energy on mass attenuation coefficients of bismuth-silicon shields in diagnostic radiology.

Recent studies have shown that the particle size of the shielding material and photon energy has significant effects on the efficiency of radiation-shielding materials. The purpose of the current study was to investigate the shielding properties of the bismuth-silicon (Bi-Si) composite containing varying percentages of micro- and nano-sized Bi particles for low-energy X-rays. Radiation composite shields composed of nano- and micro-sized Bi particles in Si-based matrix were constructed.

Layered double hydroxide nanoparticles as an appealing nanoparticle in gene/plasmid and drug delivery system in C2C12 myoblast cells.

Gene and drug delivery systems need crucial update in the issue of nanocarriers. Layered double hydroxides (LDHs) are known as biocompatible inorganic lamellar nanomaterials with versatile properties. In the present study, Zn/Al-LDH nanoparticle was synthesized and characterized by FTIR, XRD, SEM, TEM and Zeta potential tests and then intercalated with valproate and methyldopa by co-precipitation and ion exchange methods.

Determination of the dose enhancement exclusively in tumor tissue due to the presence of GNPs.

Purpose: The purpose of this study is to investigate the differences between obtained percentage dose enhancements in areas around nanoparticles in GNPs (gold nanoparticles) enriched medium and percentage dose enhancements in the entire GNPs enriched medium including nanoparticles region.

Methods And Materials: To verify the accuracy of Ir-192 source simulation, the obtained values of air kerma strength, dose rate constants, and radial dose functions were compared against previously published results. Then a 1 cm × 1 cm× 1 cm tumor volume loaded with different diameters of GNPs were considered at a source to the tumor center of 1 cm.

Iron oxide/bismuth oxide nanocomposites coated by graphene quantum dots: "Three-in-one" theranostic agents for simultaneous CT/MR imaging-guided in vitro photothermal therapy.

Background: The all-in-one nanoprobes (NPs) have drawn biomedical attention in the cancer therapy field due to simultaneously combing the capabilities of therapeutic and diagnostic methods into a single nanoprobe.

Method: In this study, we developed a theranostic probe based on superparamagnetic iron oxide (SPIO) and bismuth oxide (BiO) with graphene quantum dots (GQDs) coating to investigate the physical properties for in vitro CT/MR dual-modal biomedical imaging and cancer-specific photothermal therapy (PTT).

Result: The GQDs-Fe/Bi nanocomposites showed strong light absorbance profile with wide-band in the near-infrared region, without any sharp peak or decline.

AN ANALYSIS OF OPERATING PHYSICIAN AND PATIENT RADIATION EXPOSURE DURING RADIAL CORONARY ANGIOPLASTIES.

The objective of this study was to evaluate radiation exposure levels in conjunction with operator dose implemented, patient vascular characteristics, and other technical angiographic parameters. In total, 756 radial coronary angioplasties were evaluated in a major metropolitan general hospital in Tabriz, Iran. The classification of coronary lesions was based on the ACC/AHA system.

Shielding properties of the ordinary concrete loaded with micro- and nano-particles against neutron and gamma radiations.

The shielding properties of ordinary concrete doped with some micro and nano scaled materials were studied in the current study. Narrow beam geometry was simulated using MCNPX Monte Carlo code and the mass attenuation coefficient of ordinary concrete doped with PbO, FeO, WO and HB (Boronium) in both nano and micro scales was calculated for photon and neutron beams. Mono-energetic beams of neutrons (100-3000 keV) and photons (142-1250 keV) were used for calculations.

A REVIEW ON THE RADIATION THERAPY TECHNOLOGIST RECEIVED DOSE FROM INDUCED ACTIVATION IN HIGH-ENERGY MEDICAL LINEAR ACCELERATORS.

Despite all advantages for using high-energy photons for radiotherapy, high-energy photon beams (≥10 MV) induce photonuclear and neutron capture interactions, which result in producing radionuclide byproducts inside the Linac head and bunker, exposing radiation therapy technologists (RTTs) and patients to excessive dose. By the use of higher photon energy, greater number of monitor unit, greater field size and adding treatment accessories, induced dose rate become greater in the isocenter mainly due to activation of high-Z materials inside the Linac head. Activated radionuclides disintegrate with γ, β+ and β- rays with half-lives between 2 min up to more than 5 years.

An overview on small-field dosimetry in photon beam radiotherapy: Developments and challenges.

Small fields are more repeatedly used for radiation therapy as small segments in intensity-modulated radiotherapy or as in the form of independent fields in stereotactic radiosurgery and other novel equipment such as cyberknife and tomotherapy. Nevertheless, the application of small fields for radiotherapy of lung makes the dose calculation and planning inaccurate due to the existence of electronic disequilibrium and intrinsic deficiencies within most of the analytical dose calculation algorithms. The current review attempts to gather the information in this regard and focuses on the current progresses and retaining issues associated with this type of photon beams.

Targeted superparamagnetic nanoparticles coated with 2-deoxy-d-gloucose and doxorubicin more sensitize breast cancer cells to ionizing radiation.

Introduction: Nanoparticles are promising as a new approach to enhance chemo- radiotherapy efficiency in breast cancer mainly via targeted therapy.

Materials & Methods: SKBR3 and T47D breast cancer cells were treated with superparamagnetic mesoporous hydroxyapatite nanocomposites (SPmHANs)conjugated with 1 μM doxorubicin and 0.5 mM 2-Deoxy-d-Glucose and irradiated with 1 and 2 Gy gamma rays in vitro.

Monte Carlo modeling of a conventional X-ray computed tomography scanner for gel dosimetry purposes.

Our purpose in the current study was to model an X-ray CT scanner with the Monte Carlo (MC) method for gel dosimetry. In this study, a conventional CT scanner with one array detector was modeled with use of the MCNPX MC code. The MC calculated photon fluence in detector arrays was used for image reconstruction of a simple water phantom as well as polyacrylamide polymer gel (PAG) used for radiation therapy.