Dosimetry Problems Research Articles

Радіоізотопи цезію і досвід цитогенетичної дозиметрії за аварійних ситуацій

An analysis of data from the literature and own experimental studies related to radiation accidents with 137Cs, the ways of its entry and behavior in the human body, cytogenetic indicators for exposure dosimetry, experience in assessing the dose of victims under conditions of external exposure, and the problem of cytogenetic dosimetry of internal exposure are presented.

Exposure computational models with voxel phantoms coupled to EGSnrc Monte Carlo code

In computational dosimetry of ionizing radiation, the energy deposited in radiosensitive organs and tissues is evaluated when an anthropomorphic simulator (phantom) is irradiated using Exposure Computational Models (ECMs). An ECM is a virtual scene with a phantom positioned mathematically relative to a radioactive source. The initial state includes information like the type of primary particle, its energy, starting point coordinates, and direction. Subsequently, robust Monte Carlo (MC) codes are used to simulate the particle's mean free path, interaction with the medium's atoms, and energy deposition. These are common steps for simulations involving photons and/or primary electrons. The GDN (Research Group on Numerical Dosimetry and the Research Group on Computational Dosimetry and Embedded Systems) has published ECMs with voxel phantoms irradiated by photons using the MC code EGSnrc. This work has led to specific computational tools development for various numerical dosimetry stages, including input file preparation, ECM execution, and result analysis. Since 2004, the GDN developed in-house applications like FANTOMAS, CALDose_X, DIP, and MonteCarlo. Certain previously used phantoms are reintroduced to provide historical context in the ECMs' production timeline, emphasizing additive modifications inherent in systematic theme studies. The dosimetric evaluations used the binary version of the MASH (Male Adult mesh) phantom, converted to the SID (Dosimetric Information System) text file type. This format has been used by the group since 2021 to couple a voxel phantom to the EGSnrc user code. The ECM included an environmental dosimetry problem simulation. Most of these tools are accessible on the GDN page (http://dosimetrianumerica.org).

Applicability of the Dose Spiking Electron Paramagnetic Resonance Method for the Quantitative Measurements of Low Doses in Alanine Dosimetry

Abstract Ionizing radiation generates unpaired electrons or free radical centers in alanine. The electron paramagnetic resonance (EPR) detects, identifies, and quantifies these free radicals, proportional to the absorbed dose. The accurate measurements of low doses using EPR dosimetry with alanine are highly challenging due to (1) the weak EPR dosimetric signal from low dose alanine and measurement errors, (2) the sample anisotropy in crystalline alanine, and (3) the background signals from sample impurities. This study explores the feasibility of using the dose spiking EPR technique to overcome these challenges and decreases the detection limit up to 20 milligray (mGy) in a low dose measurement using EPR. The measurement errors from the sample anisotropy were reduced by rotating the samples relative to the constant magnetic field direction using a goniometer and averaging the resulting EPR spectra. This technique decreased the measurement errors at high doses; however, it was insufficient to decrease the detection limit and increase the measurement accuracy at low doses (<0.5 Gy). As a result, the high measurement accuracy at the high doses (>4 Gy) was exploited to increase the accuracy at the low doses using the dose spiking EPR technique. To this end, the low-dose alanine sample, undetectable and not reliably measurable in the X-band continuous wave (CW) EPR spectrometer, spikes with a high dose (4 Gy). Then, the total dose was measured and subtracted from a spike dose to get the initial low dose. This technique detected and measured the low doses with reliable accuracy (±10%). As a result, we concluded that this method has great potential to solve the low dose measurement problems in alanine dosimetry.

Lessons learnt from the recent EURADOS intercomparisons in computational dosimetry

Organized by Working Group 6 “Computational Dosimetry” of the European Radiation Dosimetry Group (EURADOS), a group of intercomparison exercises was conducted in which participants were asked to solve predefined problems in computational dosimetry. The results of these comparisons were published in a series of articles in this virtual special issue of Radiation Measurements. This paper reviews the experience gained from the various exercises and highlights the resulting conclusions for future exercises, as well as regarding the state of the art and the need for development in terms of quality assurance for computational dosimetry techniques.

The Dose Spiking Technique for Measuring Low Doses in Deciduous Teeth Enamel Using EPR Spectroscopy for Retrospective and Accident Dosimetry.

Dose estimation by electron paramagnetic resonance (EPR) has been accomplished using the standard EPR dosimetry technique (ISO protocol 13304-1 for EPR retrospective dosimetry). However, different studies showed that these techniques have high measurement errors in measuring the low doses (10-100 mGy) in enamel. This work proposes a new method to make a dosimetric signal visible and measurable at low doses. The sample was purified using both chemical and mechanical processes. The pure sample mass and position and the EPR acquisition parameters were optimized to enhance the spectrometer's sensitivity for the quantitative low dose measurements. At the same time to reduce errors from the sample and spectrum anisotropy, the total doses (low plus spike) and the spike dose (4 Gy) were measured by rotating 0 to 360 degrees (i.e., 40 degrees at a time) relative to constant magnetic field direction using a goniometer. Subsequently, the spectra were averaged after their g-factor normalization. However, at low doses (<30 mGy), the radiation induced signal (RIS) was obscured by the background signal (BGS). So, the dose spiking technique was used as an alternative method. Ten low-dose deciduous molar tooth enamel (10-100 mGy) samples were spiked to the higher doses by delivering 4 Gy and measured using the X-band continuous wave (CW) EPR (Bruker EMXmicro) spectrometer. The total dose EPR signal was distinctly visible, and the peak-to-peak (P2P) amplitude height was measured. Then, the total dose was subtracted with the spike, often called a reference sample, to determine the initial low doses. The measurement errors using this method were lower than the previous methods. These results demonstrated that this method could be promising for solving low dose measurement problems in EPR dosimetry with deciduous and permanent tooth enamel.

Bayesian and Classical Solutions for Binomial Cytogenetic Dosimetry Problem

Publisher: School of Statistics, Renmin University of China, Journal: Journal of Data Science, Title: Bayesian and Classical Solutions for Binomial Cytogenetic Dosimetry Problem, Authors: M´arcia D. Branco, Heleno Bolfarine

MONTE CARLO SIMULATION OF LIGHT SCATTERING IN HUMAN SKIN LAYERS BY SPATIAL PHOTOMETRY METHODS

The ability to register and analyze the spatial distribution of light scattered within the full solid angle is the basis for the development and improvement of information-measuring systems and software and hardware complexes for problems of optical biomedical diagnostics. The greatest contribution to light scattering at non-invasive methods of biomedical research are made by the layers of human skin, affecting the depth of probing and the resolution of diagnostic systems. The significant individual variability of the optical properties of biological tissues does not allow practically (clinically) assessing their effect on the light scattering characteristics; therefore, the use of methods for modeling the optical radiation propagation in media in the measuring tools functioning context makes it possible to provide such a prognostic analysis. The goal of this work is a comparative evaluation of the results of the light propagation in human skin layers by Monte Carlo simulation using information-measuring systems of a biomedical photometer with ellipsoidal reflectors and a goniophotometer.&#x0D; The Monte Carlo simulation results of light scattering in dermis and epidermis at a wavelength of 632.8 nm using spatial photometry methods and the "BT_Mod" software, as well as coordinates, direction, and statistical weight of photons, allows the ray-tracing in a biomedical photometer with ellipsoidal reflectors are presented in this work.&#x0D; As a result of modeling, graphs of the dependence of optical coefficients (transmission T, diffuse reflection Rd, and absorption A) for the studied tissues of various thicknesses on the value of the scattering anisotropy factor were obtained, as well as photometric images of the second focal plane of ellipsoidal reflectors when receiving a scattering spot in reflected and transmitted light. Diagrams of the averaged scattering indicatrix at three thicknesses of the epidermis and dermis were obtained for a set of biophysically significant values of the scattering anisotropy factor, based on which the integral distribution of the photons statistical weight in diffuse scattered light was analyzed. A quantitative assessment of the illuminance level of images is carried out according to the zone analysis principles in photometry by ellipsoidal reflectors. The resulting graphs of the illuminance dependence the external and middle rings of photometric images in reflected and transmitted light.&#x0D; The results of the research make it possible to analyze the spatial distribution of light scattered by the human skin layers (epidermis and dermis) within the full solid angle, which can be used in problems of optical dosimetry and medical imaging in diagnostic, endoscopic, and therapeutic methods of biophotonics.

Measuring the dose in bone for spine stereotactic body radiotherapy.

Current quality assurance of radiotherapy involving bony regions generally utilises homogeneous phantoms and dose calculations, ignoring the challenges of heterogeneities with dosimetry problems likely occurring around bone. Anthropomorphic phantoms with synthetic bony materials enable realistic end-to-end testing in clinical scenarios. This work reports on measurements and calculated corrections required to directly report dose in bony materials in the context of comprehensive end-to-end dosimetry audit measurements (63 plans, 6 planning systems). Radiochromic film and microDiamond measurements were performed in an anthropomorphic spine phantom containing bone equivalent materials. Medium dependent correction factors, kmed, were established using 6MV and 10MV Linear Accelerator Monte Carlo simulations to account for the detectors being calibrated in water, but measuring in regions of bony material. Both cortical and trabecular bony material were investigated for verification of dose calculations in dose-to-medium (Dm,m) and dose-to-water (Dw,w) scenarios. For Dm,m calculations, modelled correction factors for cortical and trabecular bone in film measurements, and for trabecular bone in microDiamond measurements were 0.875(±0.1%), 0.953(±0.3%) and 0.962(±0.4%), respectively. For Dw,w calculations, the corrections were 0.920(±0.1%), 0.982(±0.3%) and 0.993(±0.4%), respectively. In the audit, application of the correction factors improves the mean agreement between treatment plans and measured microDiamond dose from -2.4%(±3.9%) to 0.4%(±3.7%). Monte Carlo simulations provide a method for correcting the dose measured in bony materials allowing more accurate comparison with treatment planning system doses. In verification measurements, algorithm specific correction factors should be applied to account for variations in bony material for calculations based on Dm,m and Dw,w.

Determination of the neutron and gamma ray dose rates of the irradiating beam tubes of a pool-type research reactor by using Monte Carlo simulation and experimental detectors regarding radiation protection issues

In this paper, the reactor core, irradiating beam tubes, and radiological shields of a 5 MW open pool type Material Testing Reactor (MTR) are simulated in detail by using the MCNPX 2.6 code and its default library (i.e. mostly made of ENDF/B VI and VII). A safety assessment is performed and discussed based on the related health physics issues. Independently, dosimetry parameters are measured by using the Berthold LB 6411 neutron dose rate monitor and Berthold LB 123 Gamma dose rate monitor. Experimental results are used to benchmark the modeling and calculations especially regarding dosimetry, shielding, and health physics problems. Results are fairly appropriate for further calculations to be validated but some aging problems could be raised for a 50 years old research reactor particularly due to secondary gamma rate of the activated components. Then major beam tubes are characterized for high qualified irradiating applications. Moreover, external dose rates are estimated for empty beam tubes whenever radiological shields fail such as large break of beam tubes, hazardous seismic conditions, or any accident that can remove the plugs. Then, results are very important for the safety of the reactor operator to determine and establish emergency zones (i.e. yellow zones) and planning, respectively.

Determination of Optimal Modulation Amplitude for Electron Spin Resonance (ESR) Dating and Dosimetry Studies of Tooth Enamel

Fossil remains, which provide important information about past life and ecology, are especially important in natural history and life evolution. Recently, many interdisciplinary dating studies have been conducted and many different techniques have been used to investigate the data obtained in this field. Electron Spin Resonance (ESR) (or alternatively, Electron Paramagnetic Resonance, EPR) is one of the methods used in absolute dating and dosimetry studies. It is based on determination of the radiation-centered radicals obtained from the radiation dose absorbed by irradiated materials. One of the important problems in dosimetry and dating studies performed with ESR method is the dependence of experimental parameters on the accumulated dose. The accumulated dose value is effective in determining the actual result of the dating and dosimetric samples. This value is influenced from the stability of the ESR centers, experimental stages, sample preparation or measurement processes. In this study, how the modulation amplitude parameter affects ESR signal intensity in ESR dating and dosimetry studies of tooth enamel investigated. The selective archaeological animal tooth enamel sample was used from the archaeological site of Köşk Höyük, in Turkey for experimental studies. This sample was prepared with combined processes of mechanical and chemical treatment of tooth in laboratory. Tooth enamel sample was irradiated by 60Co gamma-ray source in dose of 1000 Gy at Çekmece Nuclear Research and Training Center (ÇNAEM), Turkey. After irradiation, ESR spectra were recorded at different modulation amplitude values at room temperature using X-band ESR Spectrometer. According to the results obtained, the most suitable modulation amplitude values for ESR measurements of tooth enamel sample examined in the study was found between 0.25G and 2G.

Synapse. A Neutron Spectrum Unfolding Code Based on Generalized Regression Artificial Neural Networks

In its broadest sense, the term artificial intelligence indicates the ability of an artifact to perform the same types of functions that characterize human thought. The goal of AI is to use algorithms, heuristics and methodologies based on the ways in which the human brain solves problems. Artificial neural networks recreate the structure of the human brain imitating the learning process. The Artificial neural networks theory has provided an alternative to classical computing for those problems in which traditional methods have delivered results that are not very convincing or not very convenient such as in the case of the neutron spectrometry and dosimetry problem for radiation protection purposes, using the Bonner spheres spectrometer as measurement system, mainly because many problems are encountered when trying to determine the neutron energy spectrum of a measured data. The most delicate part of the spectrometry based on this system is the unfolding process, for which several neutron spectrum unfolding codes have being developed. However, these codes require an initial guess spectrum in order to initiate the unfolding process. Their poor availability and their not easy management for the end user are other associated problems. Artificial Intelligence technology, is an alternative technique that is gaining popularity among researchers in neutron spectrometry research area, since it offers better results compared with the traditional solution methods. In this work, Synapse, a neutron spectrum unfolding code based on Generalized Regression Artificial Neural Networks technology is presented. The Synapse code is capable to unfold the neutron spectrum and to calculate 15 dosimetric quantities using the count rates, coming from a BSS as the only entrance information. The results obtained show that the Synapse code, based on GRANN technology, is a promising and innovative technological alternative for solving the neutron spectrometry and dosimetry problems.

Beam Monitors for Tomorrow: The Challenges of Electron and Photon FLASH RT

The emergent FLASH RadioTherapy (RT) uses ultrahigh dose-rate irradiation (up to 107 Gy/s instantaneous dose-rate in each μs pulse) to deliver a single high dose of irradiation in a very short time (less than 200 milliseconds). Pre-clinical studies at ultrahigh dose-rates recently showed an increased ratio between tumoricidal effect and normal tissue toxicity (therapeutic index), compared to conventional RT at standard Gy/min dose-rates. If confirmed by biological in vivo validations, this could represent a breakthrough in cancer treatment. However, the reliability and the accuracy of experimental studies are nowadays limited by the lack of detectors able to measure online the beam fluence at FLASH dose-rates. The behaviour of standard beam monitors (gas-filled ionization chambers) is compromised by the volume recombination caused by the amount of charges created per unit volume and unit time, due to the large dose-rate. Moreover, due to the lack of proper monitoring devices and to the uncertainties of its future applications, very few facilities are able to deliver at present FLASH irradiations. In this contribution, we report about the physical and technological challenges of monitoring high and ultra-high dose-rates with electrons and photon beams, starting from the pre-clinical and clinical constraints for new devices. Based on the extensive experience in silicon detectors for monitoring applications in RT with external beams, the work then investigates silicon sensors as a possible option to tackle such extreme requirements and a rugged thin and large (e.g. 10×10 cm2) flat detector (silicon-based sensor + readout electronics) is therefore outlined. This study aims at presenting the FLASH-RT dosimetry problem and analysing the possibilities for a silicon sensor to be employed as sensing device for several FLASH scenarios, including some ideas on the readout part. However, more detailed simulations and studies are demanded to delineate more precisely the technical choices to be undertaken in order to tackle the clinical accuracy required on the beam fluence, typically a few %, during photon and electron high and ultra-high irradiations, the required minimal perturbation of the beam and the high level of radiation resistance.

1O2 determined from the measured PDT dose and 3O2 predicts long-term response to Photofrin-mediated PDT

Photodynamic therapy (PDT) that employs the photochemical interaction of light, photosensitizer and oxygen is an established modality for the treatment of cancer. However, dosimetry for PDT is becoming increasingly complex due to the heterogeneous photosensitizer uptake by the tumor, and complicated relationship between the tissue oxygenation ([3O2]), interstitial light distribution, photosensitizer photobleaching and PDT effect. As a result, experts argue that the failure to realize PDT’s true potential is, at least partly due to the complexity of the dosimetry problem. In this study, we examine the efficacy of singlet oxygen explicit dosimetry (SOED) based on the measurements of the interstitial light fluence rate distribution, changes of [3O2] and photosensitizer concentration during Photofrin-mediated PDT to predict long-term control rates of radiation-induced fibrosarcoma tumors. We further show how variation in tissue [3O2] between animals induces variation in the treatment response for the same PDT protocol. PDT was performed with 5 mg kg−1 Photofrin (a drug-light interval of 24 h), in-air fluence rates (ϕair) of 50 and 75 mW cm−2 and in-air fluences from 225 to 540 J cm−2. The tumor regrowth was tracked for 90 d after the treatment and Kaplan–Meier analyses for local control rate were performed based on a tumor volume ⩽100 mm3 for the two dosimetry quantities of PDT dose and SOED. Based on the results, SOED allowed for reduced subject variation and improved treatment evaluation as compared to the PDT dose.

Monte Carlo modeling of a X-ray tube for superficial radiotherapy for evaluating the beam quality and the depth-dose distribution

The purpose of this study was to evaluate the possibility of using GEANT4 modeling package in the problems of dosimetry and treatment planning of superficial radiotherapy on the apparatus “Roentgen TA-02”. Experimental measurements and calculation of half-value layer for beams in the regular operation modes, as well as depth dose distributions were carried out in accordance with the recommendations of American Association of Physicists in Medicine (AAPM). These parameters were compared with the results of the computer model of the x-ray tube. Comparison of partial half-value layer showed high efficiency of GEANT4 package in processing of physical processes associated with x-ray radiation and interaction with the matter. The data obtained during the work with the x-ray tube model are comparable both with the estimated results and published by other authors. The x-ray beams obtained in the simulation is comparable in quality with the real ones. The simulated and real beams coincide with the depth-dose distribution in the tissue equivalent medium with high accuracy.

Численное моделирование в дозиметрических задачах ядерной медицины и радиобиологии

Численное моделирование в дозиметрических задачах ядерной медицины и радиобиологии

Performance characterisation of a real-time fiber dosimetry system using radiophotoluminescent glasses

We report the first demonstration of a real-time fiber-optic-coupled dosimetry system using Ag-activated phosphate glasses based on radiophotoluminescent (RPL) phenomena. The performance characterisation using real-time fiber RPL glass dosimetry is compared with that of real-time fiber plastic scintillation dosimetry. The inevitable build-up phenomena occurring in Ag-activated RPL glasses both during and after X-ray exposure were measured. The real-time RPL curves for the X-ray exposure region and the build-up region are analytically evaluated and fitted to the second-order polynomial functions and the sum of three exponentials, respectively. In addition, some resolved problems of real-time fiber RPL glass dosimetry are discussed.

MO-F-204-00: Preparing for the ABR Diagnostic and Nuclear Medical Physics Exams

Adequate, efficient preparation for the ABR Diagnostic and Nuclear Medical Physics exams is key to successfully obtain ABR certification. Each part of the ABR exam presents its own challenges: Part I: Determine the scope of basic medical physics study material, efficiently review this material, and solve related written questions/problems. Part II: Understand imaging principles, modalities, and systems, including image acquisition, processing, and display. Understand the relationship between imaging techniques, image quality, patient dose and safety, and solve related written questions/problems. Part III: Gain crucial, practical, clinical medical physics experience. Effectively communicate and explain the practice, performance, and significance of all aspects of clinical medical physics. All parts of the ABR exam require specific skill sets and preparation: mastery of basic physics and imaging principles; written problem solving often involving rapid calculation; responding clearly and succinctly to oral questions about the practice, methods, and significance of clinical medical physics. This symposium focuses on the preparation necessary for each part of the ABR exam. Although there is some overlap, the nuclear exam covers a different body of knowledge than the diagnostic exam. A separate speaker will address those unique aspects of the nuclear exam, and how preparing for a second specialty differs from the first. Medical physicists who recently completed each ABR exam portion will share their experiences, insights, and preparation methods to help attendees best prepare for the challenges of each part of the ABR exam. In accordance with ABR exam security policy, no recalls or exam questions will be discussed. Learning Objectives: 1.How to prepare for Part 1 of the ABR exam by determining the scope of basic medical physics study material and related problem solving/calculations 2.How to prepare for Part 2 of the ABR exam by understanding diagnostic and/or nuclear imaging physics, systems, dosimetry, safety and related problem solving/calculations 3.How to prepare for Part 3 of the ABR exam by effectively communicating the practice, methods, and significance of clinical diagnostic and/or nuclear medical physics.

MO-F-204-02: Preparing for Part 2 of the ABR Diagnostic Physics Exam

Adequate, efficient preparation for the ABR Diagnostic and Nuclear Medical Physics exams is key to successfully obtain ABR certification. Each part of the ABR exam presents its own challenges: Part I: Determine the scope of basic medical physics study material, efficiently review this material, and solve related written questions/problems. Part II: Understand imaging principles, modalities, and systems, including image acquisition, processing, and display. Understand the relationship between imaging techniques, image quality, patient dose and safety, and solve related written questions/problems. Part III: Gain crucial, practical, clinical medical physics experience. Effectively communicate and explain the practice, performance, and significance of all aspects of clinical medical physics. All parts of the ABR exam require specific skill sets and preparation: mastery of basic physics and imaging principles; written problem solving often involving rapid calculation; responding clearly and succinctly to oral questions about the practice, methods, and significance of clinical medical physics. This symposium focuses on the preparation necessary for each part of the ABR exam. Although there is some overlap, the nuclear exam covers a different body of knowledge than the diagnostic exam. A separate speaker will address those unique aspects of the nuclear exam, and how preparing for a second specialty differs from the first. Medical physicists who recently completed each ABR exam portion will share their experiences, insights, and preparation methods to help attendees best prepare for the challenges of each part of the ABR exam. In accordance with ABR exam security policy, no recalls or exam questions will be discussed. Learning Objectives: 1. How to prepare for Part 1 of the ABR exam by determining the scope of basic medical physics study material and related problem solving/calculations 2. How to prepare for Part 2 of the ABR exam by understanding diagnostic and/or nuclear imaging physics, systems, dosimetry, safety and related problem solving/calculations 3. How to prepare for Part 3 of the ABR exam by effectively communicating the practice, methods, and significance of clinical diagnostic and/or nuclear medical physics.

MO-F-204-03: Preparing for Part 3 of the ABR Diagnostic Physics Exam

Adequate, efficient preparation for the ABR Diagnostic and Nuclear Medical Physics exams is key to successfully obtain ABR certification. Each part of the ABR exam presents its own challenges: Part I: Determine the scope of basic medical physics study material, efficiently review this material, and solve related written questions/problems. Part II: Understand imaging principles, modalities, and systems, including image acquisition, processing, and display. Understand the relationship between imaging techniques, image quality, patient dose and safety, and solve related written questions/problems. Part III: Gain crucial, practical, clinical medical physics experience. Effectively communicate and explain the practice, performance, and significance of all aspects of clinical medical physics. All parts of the ABR exam require specific skill sets and preparation: mastery of basic physics and imaging principles; written problem solving often involving rapid calculation; responding clearly and succinctly to oral questions about the practice, methods, and significance of clinical medical physics. This symposium focuses on the preparation necessary for each part of the ABR exam. Although there is some overlap, the nuclear exam covers a different body of knowledge than the diagnostic exam. A separate speaker will address those unique aspects of the nuclear exam, and how preparing for a second specialty differs from the first. Medical physicists who recently completed each ABR exam portion will share their experiences, insights, and preparation methods to help attendees best prepare for the challenges of each part of the ABR exam. In accordance with ABR exam security policy, no recalls or exam questions will be discussed. Learning Objectives: 1.How to prepare for Part 1 of the ABR exam by determining the scope of basic medical physics study material and related problem solving/calculations 2.How to prepare for Part 2 of the ABR exam by understanding diagnostic and/or nuclear imaging physics, systems, dosimetry, safety and related problem solving/calculations 3.How to prepare for Part 3 of the ABR exam by effectively communicating the practice, methods, and significance of clinical diagnostic and/or nuclear medical physics.

MO-F-204-01: Preparing for Part 1 of the ABR Diagnostic Physics Exam

Adequate, efficient preparation for the ABR Diagnostic and Nuclear Medical Physics exams is key to successfully obtain ABR certification. Each part of the ABR exam presents its own challenges: Part I: Determine the scope of basic medical physics study material, efficiently review this material, and solve related written questions/problems. Part II: Understand imaging principles, modalities, and systems, including image acquisition, processing, and display. Understand the relationship between imaging techniques, image quality, patient dose and safety, and solve related written questions/problems. Part III: Gain crucial, practical, clinical medical physics experience. Effectively communicate and explain the practice, performance, and significance of all aspects of clinical medical physics. All parts of the ABR exam require specific skill sets and preparation: mastery of basic physics and imaging principles; written problem solving often involving rapid calculation; responding clearly and succinctly to oral questions about the practice, methods, and significance of clinical medical physics. This symposium focuses on the preparation necessary for each part of the ABR exam. Although there is some overlap, the nuclear exam covers a different body of knowledge than the diagnostic exam. A separate speaker will address those unique aspects of the nuclear exam, and how preparing for a second specialty differs from the first. Medical physicists who recently completed each ABR exam portion will share their experiences, insights, and preparation methods to help attendees best prepare for the challenges of each part of the ABR exam. In accordance with ABR exam security policy, no recalls or exam questions will be discussed. Learning Objectives: 1.How to prepare for Part 1 of the ABR exam by determining the scope of basic medical physics study material and related problem solving/calculations 2.How to prepare for Part 2 of the ABR exam by understanding diagnostic and/or nuclear imaging physics, systems, dosimetry, safety and related problem solving/calculations 3.How to prepare for Part 3 of the ABR exam by effectively communicating the practice, methods, and significance of clinical diagnostic and/or nuclear medical physics.