Introduction: Despite advances in cancer therapy, many treatments result in significant side effects and inconsistent remission. This review was aimed at exploring the potential of Auger electrons (AEs) as a novel, highly localized approach to cancer treatment. Materials & Methods: Relevant studies were reviewed to examine the mechanism of action of AEs emitted from radioisotopes, their DNA-damaging effects, and their selective activity in cancer cells. The analysis also included recent developments in cancer cell detection based on surface charges, radionuclide delivery systems, and the role of proton tunneling and low-energy electrons in DNA disruption. Results:  Auger electrons, characterized by low energy and high linear energy transfer (LET), induce lethal DNA damage with minimal impact on surrounding healthy tissue. They act through direct DNA interaction or indirectly via water ionization. Detection methods based on cell surface charge properties showed promise in improving cancer cell targeting. Additionally, advancements in radionuclide carriers enhanced delivery precision. Insights into proton tunneling supported the biological relevance of low-energy electrons in therapeutic applications. Conclusion:  Auger electron therapy offers a promising, targeted strategy for cancer treatment with reduced collateral damage. Continued research is needed to refine delivery systems and better understand electron-cell interactions to maximize therapeutic outcomes.

Determination of the relative biological effectiveness (RBE) of Auger electrons is a challenging task in radiobiology. In this study, we have estimated the RBE of internal conversion (IC) and Auger electrons released during Gadolinium neutron capture reaction (GNCR) by means of biological weighting functions (BWFs) with microdosimetric approach. Regarding the different distribution of Gadolinium (Gd) relative to the DNA as a target, the microdosimetric parameters of the Gd electrons were calculated using the Geant4 Monte Carlo toolkit and ROOT software. Assuming Gd infiltration into the cells and uniform distribution inside the Cell, the lineal energy distribution of Gd electrons in DNA was used instead of the lineal energy distribution of external radiations in the micrometer-diameter targets, which has been conventionally used in the mentioned methods. The results show that the calculated RBE values of Gd electrons using BWFs (2. 68) for the case where Gd distributed at the center of the DNA are approximately equivalent to the RBE value of the therapeutic neutrons, which were measured in the literatures with the same biological conditions. According to the results, although the changes of the RBE of Gd electrons to the different distribution of Gd relative to the DNA are small, the amount of biological dose of the Gd electrons in the DNA is strongly dependent on the Gd distribution. In the case where Gd distributed at the center of DNA, the mean biological dose of Gd electrons in DNA during one GNCR (227. 8 kGy. Eq) is large enough for occurring double-strand breaks (DSB) of the DNA. If we have accurate information about the spatial distribution of Gd or Auger-electron emitters inside the cell, by comparing to the results obtained in this study, we can have a better estimation of the RBE of the Gd electrons or in general Auger electrons.

In current study, the relative biological effectiveness (RBE) values relevant to the various Iodine radioisotopes, have been assessed to compare the performance of the MCSD and GEANT4-DNA Monte Carlo codes at low energy regions. After the calculation of the Auger electrons energy spectrum, obtained from the Iodine radioisotopes including 123I, 124I, and 125I through the GEANT4 Monte Carlo code, the calculation of the RBE values was performed through the GEANT4-DNA extension by considering the B-DNA model. In addition, the RBE values were also estimated by the MCDS code in completely aerobic conditions. The results of this study showed that employing the GEANT4-DNA-option4 physics by GEANT4-DNA extension in the physical stage provides near results in comparison with MCDS code for the radiobiological assessments and RBE estimation. The obtained highest difference values in this study were related to the use of GEANT4-DNA-option2 physics which varies from 22.30% to 24.60% for the studied radioisotopes. Since double strand damages along the DNA molecule can eventually lead to the cell death, and due to the appropriable agreement between the calculated results of RBEDSB values through the MCDS and GEANT4-DNA codes, it can be deduced that the MCDS code provides accurate results for the radiation induced DNA damage.

Introduction: Now day Ionizing radiation has found increasing applications in cancer treatment. However, in the treatment different kinds and size of tumors especially metastatic and small size tumors, conventional methods of external radiation therapy are not common. In radionuclide therapy, the use of monoclonal antibodies has made it possible to achieve maximum dose to small size tumor and minimum dose to healthy tissue. In the use of electrons Auger-emitter radionuclides, due to the short range and high cytotoxicity, there should be a high degree of precision. For this reason, Monte Carlo methods and simulations can be used in higher accuracy. In this study, the cellular dose of 111In radionuclide was calculated and validated using the Monte Carlo method. Materials and Methods: In this research, the Geant4 Monte Carlo code was used with three low energy physical models: Geant4-DNA, Livermore, Penelope and Standard Physics. Correspondingly, distribution of radiation from radiation sources and the location of the source was considered uniform and randomly within the volume, respectively. The results of MCNP and MIRD codes published data were used for comparison. Results: In the correlation study, the S-value results of self and cross-absorption between the two codes indicated show a good agreement between the data of the MCNP code and the results of different physics models of Geant4 code. Conclusion: Although there are some differences between the results of the codes which are mentioned in results, finally the comparison indicates that the acceptability use of Geant4 in the cellular dosimetry. So, for therapeutic and diagnostic applications of the 111In as an Auger electrons-emitter radionuclide we can recommend this code for dose calculations.

Auger electrons (AEs) are emitted by radionuclides such as , , , that decay by electron capture or internal conversion . These low energy electrons deposit their energy over nanometer-micrometer distance which results in high linear energy transfer that leads to lethal damage in cancer cells. Therefore, radiotherapeutics including the AE-emitting radionuclides have great potential for cancer treatment. The highest energy deposition occurs in , and the diameter of double-strand DNA is about , hence, when AEs are released in the vicinity of the cell nucleus, they can cause lethal double DNA strand breaks. Targeted radionuclide therapy in which radionuclides are carried by nanostructures can be very successful in cancer treatment. Transportation of important radionuclides using organic and inorganic nanostructures has an important role in development of radiotherapeutics and radionuclide therapy. The high surface area to volume ratio of nanoparticles makes them suitable for adding polymers or biologically active molecules including therapeutic or diagnostic elements which have high affinity to the receptors on tumor cells. Therefore, simultaneous imaging and radiotherapeutic is possible. In addition, using high-Z nanoparticles increases the emission of photoelectrons and Auger electrons resulting the more effectiveness of the treatment. Therefore, nanostructure materials and design are very important. In this paper, we discuss the properties of Auger electron and the the transportation of Auger electron emitters by nanostructures in cancer therapy.

We give an overview of recent work on charge degrees of freedom of strongly correlated electrons on geometrically frustrated lattices. Special attention is paid to the checkerboard lattice, i.e., the two-dimensional version of a pyrochlore lattice and to the kagomé lattice. For the checkerboard lattice it is shown that at half filling when spin degrees of freedom are neglected and at quarter filling when they are included excitations with fractional charges ±e/2 may exist. The same holds true for the three-dimensional pyrochlore lattice. In the former case the fractional charges are confined. The origin of the weak, constant confining force is discussed and some similarities to quarks and to string theory are pointed out. For the checkerboard lattice a formulation in terms of a compact U(1) gauge theory is described. Furthermore a new kinetic mechanism for ferromagnetism at special fillings of a kagomé lattice is discussed.

Purpose: The biological effects of ionizing radiation at the cellular and subcellular scales are studied by the number of breaks in the DNA molecule that provides a quantitative description of the stochastic aspects of energy deposition at cellular scales. The Geant4 code represents a suitable theoretical toolkit in microdosimetry and nanodosimetry. In this study, radiation effects due to Auger electrons emitting radionuclides such as 195𝑚 𝑃 𝑡 113𝑚 𝐼 𝑛 , 125𝐼 , and 201𝑇 𝑙 are investigated using the Geant4-DNA. Materials and Methods: The Geant4-DNA is the first Open-access software for the simulation of ionizing radiation and biological damage at the DNA scale. Low-energy electrons, especially Auger electron from Auger electron emitting radionuclides during the slowing-down process, deposit their energy within a nanometer volume. Results: The average number of Single-Strand Breaks (SSB) and Double-Strand Breaks (DSB) of DNA as a function of energy and distance from the center of the DNA axis are shown. Conclusion: The highest DSBs yield has occurred at energies less than 1 keV, and 195𝑚 𝑃 𝑡 induces a higher DSBs yield.