Introduction
Accurate dosimetry in ophthalmic plaque brachytherapy is essential due to steep dose gradients and the proximity of critical ocular structures. Current clinical practice relies on manufacturer-certified data with limited independent verification. This study reports on the development of a novel system for rapid pre-insertion validation of Ru-106 and I-125 plaques using...
Modelling the early DNA damage induced by radiation is critical for understanding its biological impact. Radiation traversing a cell induces DNA damage through both physical interactions (direct damage) and chemical interactions of radiochemical species (indirect damage) with the DNA strand. Through the combination of DNA geometry models, physics models and chemical tracking, the early DNA...
The Elekta Unity is an MR-LINAC that integrates a 7 MV linear accelerator with a 1.5 T MRI in order to provide adaptive online radiotherapy. Using Geant4 version 11.1 and the EMStandard Option 4 Physics Constructor a highly accurate simulation of the Elekta Unity MR-LINAC was developed to produce patient specific dose maps. These dose maps are utilised for the training of a robust dose...
Precise source localisation is vital for safe HDR brachytherapy. This study examines a fibre-optic dosimeter for real-time tracking of a ยนโนยฒIr source, using a new calibration approach that incorporates fluorescence and Cherenkov contributions alongside scintillation signals. Unlike conventional stem-effect correction methods, which rely on hardware modifications or spectral separation, this...
Ultra-high dose-rate, very high-energy electrons (VHEE, electrons with energy greater than 50 MeV) are of increasing interest to the field of radiotherapy, due to their ability to penetrate deeply into tissue and reach tumours that are out of reach to clinical electrons of lower energies. Linacs capable of reaching these energies are also capable of exceedingly high dose-rates, many orders of...
Ocular melanoma is the most common intraocular malignancy in adults and is potentially life-threatening if left untreated. A common alternative to enucleation (removal of the eye) is eye plaque brachytherapy, where small Iodine-125 seeds are arranged on the surface of a circular ophthalmic plaque. Currently, there is no rapid method to measure the activity of individual seeds, preventing...
Heavy-ion therapy (HIT) is a growing cancer treatment modality due to its dose sparing and high biological effectiveness. However, a major challenge in heavy-ion therapy is nuclear fragmentation, where primary ions break into smaller particles, resulting in complex secondary radiation fields. Monte Carlo simulations are commonly used to study the secondary radiation field, such as to estimate...
Approximately half of all cancer patients receive radiotherapy, with external beam radiotherapy being a cornerstone of treatment. The objective is to deliver radiation with high precision to achieve tumor control while minimizing exposure of surrounding healthy tissue. Despite major technological advances, some radioresistant tumors remain incurable with conventional methods.
Microbeam...
Beamโshaping assembly (BSA) design using Monte Carlo techniques for acceleratorโbased boron neutron capture therapy (BNCT) requires accurate modelling of lightโion reactions on thin or thick targets, which define the neutron source term for subsequent beam shaping. Geant4โฏ11.1.3, PHITSโฏ3.33, FLUKAโฏ4โ4.0 and MCNPโฏ6.3 have been benchmarked for thickโtarget neutron yield and spectra from...
This talk introduces Quantum-AI Biophotonic Diagnostics for Point-of-Care Brain Tumor Screening, a next-generation framework that unites quantum computing, artificial intelligence, and nanoscale biophotonics to transform biomedical diagnostics. We present an integrated approach for early cancer detection that combines plasmonic biophotonic sensors with a quantum machine learning (QML)...
Proton therapy offers a more conformal dose distribution and higher linear energy transfer (LET) than conventional X-ray therapy, reducing dose to healthy tissue while enhancing tumour control. The relative biological effectiveness (RBE) quantifies radiation-induced tissue damage, and accurate RBE values are critical for treatment planning. Although an RBE of 1.1 is commonly assumed for proton...
A GEANT4 study into the concept for a simple, silicon-based, electronic fast neutron dosimeter for radiation protection purposes is presented. The circular shaped dosimeter utilised the fluence approach to neutron dosimetry to achieve a dose equivalent response. This approach involved using the neutron dose equivalent conversion coefficients to relate the dosimetry quantity fluence, to the...
Radiation therapy is an important component of cancer treatment. Microbeam radiation therapy (MRT) is an experimental irradiation technique in which a synchrotron-generated X-ray beam is spatially fractionated into an array of quasi-parallel microbeams by a multislit collimator, leading to an inhomogeneous dose distribution in the target. In preclinical studies, this results in good tumor...
Geant4 is an open-source Monte Carlo radiation physics simulation code, extensively used in medical physics, including verification of radiotherapy treatment planning systems, and the design of equipment for radiotherapy and nuclear medicine. It is also used in medical imaging for dosimetry, to improve detectors and reconstruction algorithms, and for radiation protection assessments. Geant4...
Why have we chosen to write yet another book on synchrotron light? After all, the classical physics of synchrotron-light emission is an established field, and many excellent books on the topic have already been published. In this talk we will present our recently published book and the educational approach we took.
Most existing textbooks on the subject either cover a wide range of...
BACKGROUND: X-ray Computed Tomography dose levels have been varying among modalities and scanning body regions due to the absence of an incessant routine follow-up. Thus, the study aimed to compute the dose index discrepancies in Ethiopia for the most recurring scan protocols (head, chest, abdomen, and pelvis).
METHODS: Due to the rare existence of functional CT scanners in Ethiopia, a...
