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Abstract Background The aim of this study was to find the entrance skin dose (ESD) for diagnostic radiation qualities RQRs, RQAs and RQTs given in IAEA technical report series No. 457 using direct and indirect methods of measurement. Measurements were done for 5 × 5, 10 × 10, 15 × 15, 20 × 20 and 25 × 25 cm2 field sizes and 70, 80, 90 and 100 cm source to surface distance (SSD) using shadow-free diagnostic (SFD) chamber and water phantom having dimension 30 × 30 × 30 cm3. ESD direct measurements were done by placing SFD chamber on the surface of water phantom, while in the case of indirect measurements, air kerma values were obtained. Results ESD values for different selected radiation qualities RQR2, RQR5, RQR8, RQR10, RQA2, RQA5, RQA8, RQA10, RQT8, RQT9 and RQT10 were found to be in the range of 0.0045–5.11 mGy per examination. Conclusions Results obtained were found to be comparable with ESD values published in the literature. The obtained results in this research would help in establishing the national diagnostic reference levels (DRLs) which would help in the optimization of diagnostic imaging procedures. It would also help the radiographers to optimize field sizes and SSDs in order to reduce dose to the patients thereby ensuring good radiological practices, and this would reduce the stochastic risk to the patients caused by the ionizing radiations.

Background: The aim of this study was to find the entrance skin dose (ESD) for diagnostic radiation qualities RQRs, RQAs and RQTs given in IAEA technical report series No. 457 using direct and indirect methods of measurement. Measurements were done for 5 × 5, 10 × 10, 15 × 15, 20 × 20 and 25 × 25 cm2 field sizes and 70, 80, 90 and 100 cm source to surface distance (SSD) using shadow-free diagnostic (SFD) chamber and water phantom having dimension 30 × 30 × 30 cm3. ESD direct measurements were done by placing SFD chamber on the surface of water phantom, while in the case of indirect measurements, air kerma values were obtained. Results: ESD values for different selected radiation qualities RQR2, RQR5, RQR8, RQR10, RQA2, RQA5, RQA8, RQA10, RQT8, RQT9 and RQT10 were found to be in the range of 0.0045–5.11 mGy per examination. Conclusions: Results obtained were found to be comparable with ESD values published in the literature. The obtained results in this research would help in establishing the national diagnostic reference levels (DRLs) which would help in the optimization of diagnostic imaging procedures. It would also help the radiographers to optimize field sizes and SSDs in order to reduce dose to the patients thereby ensuring good radiological practices, and this would reduce the stochastic risk to the patients caused by the ionizing radiations. [ABSTRACT FROM AUTHOR]

Background: Electromagnetic induction hyperthermia is a promising method to treat the deep-seated tumors such as brain and prostatic tumors. This technique is performed using the induction of electromagnetic waves in the ferromagnetic cores implanted at the solid tumor.Objective: This study aims at determining the conditions of the optimal thermal distribution in the different frequencies before performing the in vitro cellular study.Material and Methods: In this experimental study, the i-Cu alloy (70.4-29.6; wt%) was prepared and characterized and then the parameters, affecting the amount of induction heating in the ferromagnetic core, were investigated. Self-regulating cores in 1, 3, 6, and 9 arrangements in the water phantom with a volume of 2 cm3 were used as a replacement for solid tumor.Results: Inductively Coupled Plasma (ICP) analysis and Energy Dispersive X-ray Spectroscopy (EDS) show the uniformity of the alloy after 4 times remeling by vacuum arc remelting furnace. The Vibrating Sample Magnetometer (VSM) shows that the Curie temperature (TC) of the ferromagnetic core is less than 50 °C. Temperature profile with a frequency of 100-400 kHz for 30 min, was extracted by infrared imaging camera, indicating the increase temperature in the range of 42 °C to 46 °C. Conclusion: The optimum conditions with used hyperthermia system are supplied in the frequency of 100 kHz, 200 kHz and 400 kHz with 6, 3 and 1 seeds, respectively. It is also possible to induce a temperature up to 50 °C by increasing the number of seeds at a constant frequency and power, or by increasing the applied frequency at a constant number of seeds.

Background: Electromagnetic induction hyperthermia is a promising method to treat the deep-seated tumors such as brain and prostatic tumors. This technique is performed using the induction of electromagnetic waves in the ferromagnetic cores implanted at the solid tumor. Objective: This study aims at determining the conditions of the optimal thermal distribution in the different frequencies before performing the in vitro cellular study. Material and Methods: In this experimental study, the i-Cu alloy (70.4-29.6; wt%) was prepared and characterized and then the parameters, affecting the amount of induction heating in the ferromagnetic core, were investigated. Self-regulating cores in 1, 3, 6, and 9 arrangements in the water phantom with a volume of 2 cm3 were used as a replacement for solid tumor. Results: Inductively Coupled Plasma (ICP) analysis and Energy Dispersive X-ray Spectroscopy (EDS) show the uniformity of the alloy after 4 times remeling by vacuum arc remelting furnace. The Vibrating Sample Magnetometer (VSM) shows that the Curie temperature (TC) of the ferromagnetic core is less than 50 °C. Temperature profile with a frequency of 100-400 kHz for 30 min, was extracted by infrared imaging camera, indicating the increase temperature in the range of 42 °C to 46 °C. Conclusion: The optimum conditions with used hyperthermia system are supplied in the frequency of 100 kHz, 200 kHz and 400 kHz with 6, 3 and 1 seeds, respectively. It is also possible to induce a temperature up to 50 °C by increasing the number of seeds at a constant frequency and power, or by increasing the applied frequency at a constant number of seeds. [ABSTRACT FROM AUTHOR]

The water phantom is used for LINAC calibration to measure absorbed dose radiation. Practically, it requires a long preparation time and is considered less efficient. To increase efficiency, the medical physics team in a hospital uses slab phantom as the calibration tool. Consequently, the correction factor is crucial to define the equivalence of the absorbed doses resulted from slab phantom. The absorbed dose measurement was performed according to the IAEA TRS-398 dosimetry protocol with a cylindrical ionization chamber detector for 6 MV photon beam and electron beams from Elekta Synergy Platform 154029 LINAC with 6 MeV, 8 MeV, 10 MeV, and 12 MeV energy variations. The field size for slab and water phantom is 30 cm x 30 cm x 30 cm. Based on the TRS-398 protocol, the correction factor of the slab phantom calculated based on absolute dosimetry for 6 MV photons beam, the electron beam of 6 MeV, 8 MeV, 10 MeV, and 12 MeV are 1.0018; 0.9995; 0.9979; 1.0041 and 1.0068, respectively. As a result, the absorbed dose radiation measured by the calibrated slab phantom using the resulted correction factor has an equivalent amount to the water phantom.

This study optimized the ultrasound image of carotid artery stenosis using Taguchi dynamic analysis and an indigenous water phantom. Eighteen combinations of seven essential factors of the ultrasound scan facility were organized according to Taguchi's L18 orthogonal array. The seven factors were assigned as follows: (1) angle of probe; (2) signal gain; (3) resolution vs. speed; (4) dynamic range; (5) XRES; (6) zoom; (7) time gain compensation. An indigenous water phantom was customized to satisfy the quantified need in Taguchi's analysis. Unlike the conventional dynamic Taguchi analysis, an innovative quantified index, the figure of merit (FOM), was proposed to integrate four specific quality characteristics, namely (i) average difference between the practical scan and theoretically preset area (78.5, 50.2 and 12.6 mm2) of stenosis, (ii) standard deviation of the average, (iii) practical scan's sensitivity β to various stenosis diameters (10, 8, and 4 mm), and (iv) correlation coefficient r2 of the linear regressed sensitivity curve. The highest value (FOM = 0.413) was furnished by the optimal combination of factors on 18 groups under study, yielding high r2 and low β or standard deviation values and the best quality of ultrasound images for the further clinical diagnosis. The comparison between FOM and the conventional signal-to-noise (S/N) ratio in Taguchi's analysis revealed that FOM compiled more quality characteristics that were superior by nature to fulfill the practical need in clinical diagnosis. The alternative choice in ultrasound scan optimization can be based on stenosis diameter variation from a different perspective to be explored in the follow-up study. [ABSTRACT FROM AUTHOR]

Object: Optimization of common iliac artery sonography images using an indigenous water phantom and Taguchi's analysis was successfully performed to improve the diagnostic accuracy in routine cardiac examination. Methods: A water phantom with two major compartments was developed, which satisfied Taguchi's unique criterion of optimization analysis. Two or three levels were assigned to five factors, namely, (A) the probe angle, (B) water depth, (C) sonography preset frame rate, (D) amplitude gain, and (E) imaging compression ratio. The resulting Taguchi's L18 orthogonal array contained 18 combinations of 5 factors, ensuring the same confidence level as a realm of 162 (21 × 34) combinations. The signal-to-noise ratio (S/N) was defined as the minimal difference between the practical survey and predicted areas of 50 mm2 for the sonography imaging scans. The artifact was customized by creating stenosis with a diameter of 8 mm inside a silicon pipe with a diameter of 19 mm. Results: The derived optimal parameters included (A) a zero probe angle, (B) water depth of 6 cm, (C) frame rate of 45 Hz, (D) amplitude gain of 50%, and (E) compress ratio of 50% from 3 independent measurements in each group. Further ANOVA confirmed that the frame rate was a dominant factor, with ss (sum of squared variances) of 56.6%, whereas the error and other terms were suppressed to 20.3% and 11.9%, respectively. The risks of the inappropriate setting of S/N were also discussed to avoid any misinterpretations. Conclusions: The quantified water phantom combined with Taguchi's approach proved to be instrumental in optimizing the sonography image scan quality in routine cardiac examination. [ABSTRACT FROM AUTHOR]

To analyze the biological effects of radiation, it is important that the conditions of in vitro experiments match closely with those of in vivo experiments. In this study, we constructed an irradiation system to conduct irradiation experiments under conditions similar to those of in vivo experiments. The Dongnam Institute of Radiological and Medial Sciences has a gamma irradiator including 60Co radioisotope for research purposes and accreditation for standard calibration of the ion chamber. The temperature of the water phantom was maintained the same as that of the normal human body, and the physical dosimetry was carried out accurately using the ion chamber with traceability. We report the measurement of lateral profiles, depth profiles, and absorbed dose rate in water, Dw, at the irradiation location of the blood samples using a farmer-type ion chamber. We simulated the source, collimator, irradiator, phantom, and extra structure of the gamma irradiation system using the Monte Carlo code and compared the simulated and the experimental results. The experimentally and theoretically evaluated dose rates were 0.2975 ± 0.0055 Gymin–1 (at coverage factor k = 2) and 0.2978 ± 0.0052 Gymin–1 (at coverage factor k = 2) at source-to-surface distance of 100 cm and 5 gcm–2 depth in the water phantom, respectively. Blood irradiation will be conducted in vitro, under conditions similar to in vivo conditions, to provide the dose-response curve based on dosimetry with traceability.

This study aimed to evaluate changes in the deformation of the entrance window on a phantom for a horizontal beam geometry with a window thickness of 5 mm. The window deformation over time was measured using a dial indicator for 12 h after water filling. The window deformation was in the range of 0.17–0.37 mm among the three phantoms. The change in deformation over time was found to be 0.06 mm or less 12 h after filling the phantom. For off-center measurements, the maximum difference in variation among the five points in each of the three phantoms was 0.12, 0.11, and 0.07 mm. The window deformation on the phantom for a horizontal beam geometry with the window thickness of 5 mm was considered almost negligible when appropriately used. However, it is important to control the quality of the phantom according to the usage conditions. [ABSTRACT FROM AUTHOR]

A Double Layer Beam Shaping Assembly (DLBSA) was designed to produce epithermal neutrons for BNCT purposes. The Monte Carlo N-Particle eXtended program was used as the software to design the DLBSA and phantom. Distribution of epithermal neutron and gamma flux in the DLBSA and phantom and absorbed dose in the phantom were computed using the Particle and Heavy Ion Transport code System program. Testing results of epithermal neutron beam irradiation of the water phantom showed that epithermal neutrons were thermalized and penetrated the phantom up to a depth of 12 cm. The maximum value of the absorbed dose was 2 × 10-3 Gy at a depth of 2 cm in the phantom.

Copyright of Nuclear Technology & Radiation Protection is the property of Vinca Institute of Nuclear Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Object: Optimization of common iliac artery sonography images using an indigenous water phantom and Taguchi’s analysis was successfully performed to improve the diagnostic accuracy in routine cardiac examination. Methods: A water phantom with two major compartments was developed, which satisfied Taguchi’s unique criterion of optimization analysis. Two or three levels were assigned to five factors, namely, (A) the probe angle, (B) water depth, (C) sonography preset frame rate, (D) amplitude gain, and (E) imaging compression ratio. The resulting Taguchi’s L18 orthogonal array contained 18 combinations of 5 factors, ensuring the same confidence level as a realm of 162 (21 × 34) combinations. The signal-to-noise ratio (S/N) was defined as the minimal difference between the practical survey and predicted areas of 50 mm2 for the sonography imaging scans. The artifact was customized by creating stenosis with a diameter of 8 mm inside a silicon pipe with a diameter of 19 mm. Results: The derived optimal parameters included (A) a zero probe angle, (B) water depth of 6 cm, (C) frame rate of 45 Hz, (D) amplitude gain of 50%, and (E) compress ratio of 50% from 3 independent measurements in each group. Further ANOVA confirmed that the frame rate was a dominant factor, with ss (sum of squared variances) of 56.6%, whereas the error and other terms were suppressed to 20.3% and 11.9%, respectively. The risks of the inappropriate setting of S/N were also discussed to avoid any misinterpretations. Conclusions: The quantified water phantom combined with Taguchi’s approach proved to be instrumental in optimizing the sonography image scan quality in routine cardiac examination.

Purpose: To design and commission a water phantom suitable for constrained environments and magnetic fields for magnetic resonance (MR)‐guided proton therapy. Methods: A phantom was designed, to enable precise, remote controlled detector positioning in water within the constrained environment of a magnet for MR‐guided proton therapy. The phantom consists of a PMMA enclosure whose outer dimensions of 81×40×12.5cm3 were chosen to optimize space usage inside the 13.5‐cm bore gap of the magnet. The moving mechanism is based on a low‐height H‐shaped non‐ferromagnetic belt drive, driven by stepper motors located outside of the magnetic field. The control system and the associated electronics were designed in house, with similar features as available in commercial water phantoms. Reproducibility as well as accuracy of the phantom positioning were tested using a high‐precision Leica AT 402 laser tracker. Laterally integrated depth dose curves and lateral beam profiles at three depths were acquired repeatedly for a 148.2 MeV proton beam in water. Results: The phantom was successfully operated with and without applied magnetic fields. For complex movements, a positioning uncertainty within 0.16 mm was found with an absolute accuracy typically below 0.3 mm. Laterally integrated depth dose curves agreed within 0.1 mm with data taken using a commercial water phantom. The lateral beam offset determined from beam profile measurements agreed well with data from Monte Carlo simulations. Conclusion: The phantom is optimally suited for detector positioning and dosimetric experiments within constrained environments in high magnetic fields. [ABSTRACT FROM AUTHOR]

A method for controlling the synchrotron beam intensity during proton irradiation of patients is proposed. The control is based on the installation of two precision "warm-liquid" pad chambers, one at the exit from the last scanning magnet and the other in front of the patient. The intensity density of the beam directed to the irradiated target using two pad chambers is measured. The measured intensity density profiles are compared with specified parameters; the beam is turned off if the measured parameters deviate from the permissible ones. The result is an increase in the proton therapy conformity due to the continuous dose and dose field boundary control in the target for each accelerator pulse. [ABSTRACT FROM AUTHOR]

Purpose: Three‐dimensional (3D) dosimetry is a necessity to validate patient‐specific treatment plans in particle therapy as well as to facilitate the development of novel treatment modalities. Therefore, a vendor‐agnostic water phantom was developed and verified to measure high resolution 3D dose distributions. Methods: The system was experimentally validated at the Marburger Ionenstrahl‐Therapiezentrum using two ionization chamber array detectors (PTW Octavius 1500XDR and 1000P) with 150.68 MeV proton and 285.35 MeV/u 12C beams. The dose distribution of several monoenergetic and complex scanned fields were measured with different step sizes to assess the reproducibility, absolute positioning accuracy, and general performance of the system. Results: The developed system was successfully validated and used to automatically measure high resolution 3D dose distributions. The reproducibility in depth was better than ±25 micron. The roll and tilt uncertainty of the detector was estimated to be smaller than ±3 mrad. Conclusions: The presented system performed fully automated, high resolution 3D dosimetry, suitable for the validation of complex radiation fields in particle therapy. The measurement quality is comparable to commercially available systems. [ABSTRACT FROM AUTHOR]

Experimental measurements of the Bragg peak depth by two methods: the air ionization chamber and the digital imaging detector (DIDE) for proton energies of 50, 100, and 170 MeV are compared. The principle of operation of a new detector type, i.e., the DIDE for measuring the energy release region of the proton beam passing through a water phantom is considered. The DIDE detector is a coordinate meter of the Bragg peak depth profile which, using a known energy dependence of the dose, i.e., "quality curve," can recalculate the coordinate to the doze depth profile (with controlled accelerator output stability). It is indicated that the binning (pixel summing) mode is most important for light collection from radioluminescence. In measuring the coordinate region of energy release (Bragg peak) by the detector, the result appears almost instantaneously and with an accuracy regulated by the IAEA. [ABSTRACT FROM AUTHOR]

Strain and impurity defects in carbon nanotubes (CNTs) particularly their potentiality as a new TL material has been studied over the years. In this research, our main objective is to explore the suitability of using CNTs and its composites in the area of TL dosimeter. For this purpose, a study was carried out between the TL responses of the dosimeters TLD-100, TLD-7000 and NaI-LiF pellets. To carry out this research, equivalent irradiations were performed with these pellets using clinical linear accelerator (LINAC) under 6 MV X-ray photon beam. The dose range was from 0.5 to 5 Gy. During irradiation, the dose rate was kept constant at 300 MU/min. TLD reader was used to readout the samples in a flowing N2 atmosphere to reduce surface oxidation. During readout, pre-heat temperature was set initially at 50 °C, acquired temperature rate 10 °C/s and maximum annealed temperature was 300 °C. Response of TLD-100 under varying dose was typically linear for any doses but other dosimeters TLD-7000 showed supra-linearity beyond 2 Gy and NaI-LiF pellets showed sub-linearity response after 2 Gy. The TL glow peak of CNTs indicated that it was lying somewhere away from 300 °C. [ABSTRACT FROM AUTHOR]

The purpose of this study is to measure doses delivered at different depths in water phantom at vertical position in comparison with the actual planning in order to verify the dose delivered to the tumor in addition to the measurement of the effect penumbra dose to assess the dose leaking to the healthy soft tissue. Percentage depth dose (PDD) values was measured at field sizes (5×5,10×10,15×15, and 20×20) cm2, and the depth dose was measured between (0- 16) cm deep at 4cm intervals, for both energies 6 MeV and 10 MeV X-ray beam. Other readings were taken at different distances 1cm and 2cm outside of the actual beam in orthogonal directions at depth of 4 cm. These measurements were designed to measure the penumbra dose produced outside the central beam. Results show that the high similarity between water phantom and actual tissue for this reason water is taken as phantom for Quality Assurance (QA) and calculation the depth dose. The similar results may appear strange as the actual planning depth dose is taken in the chest wall where there is bone and soft tissue. The increase in the field size, increases the percentage of surface dose, this could be caused by an increase in the amount of scattering in the larger fields. There is almost no difference in depth dose between homogenous and non homogenous planning also similar to the water phantom. Because of higher photon energy 6MeV and 10MeV the bone has no influence in absorption from the soft tissue. A slight change in the depth dose with increase in the field size may be caused by the scattered radiation. [ABSTRACT FROM AUTHOR]

Introduction: The dosimetry of the brachytherapy sources is performed in the water source medium according to protocol TG-43U1. To achieve a resonable results on treatment, the use of the water material for all body tissues can be one of the faulty sources in delivering the correct dose to the tumor. Thus, we have focused on the dosimetry parameters in fat density 0.95 gr/cm3 and the muscle with density 1.05 gr/cm3 in the present study. The results are compared with the results of the water phantom to show the accurate accessment via the differences of the results. Methods: Dissymmetry simulations for determining the parameters of the radial dose function and the anisotropy function in fat tissues, muscle and water phantom distances and different angles has been using MCNP4C code. Results: The greatest relative differences of the phantom radial dose function of the fat tissue at distances below 1cm approximately reached 13%; and this rate increased, when the distance from the source increased; whereas at the distance of 5cm from the source, it approximately reached 167%. In the muscle tissue, the relative difference of these parameters was about 3% at the distance of 0.5cm, while at the distance of 5cm from the source, it approximately increased 16%. The maximum relative difference of the anisotropy parameter of the fat and muscle tissue phantom compared with the water were observed more than 2% and 3%, respectively. Conclusion: In the clinical application of the 103Pd brachytherapy source, which is contracted in the treatment of the adjacent malignant tumors to the fat and muscle tissues, the correct decisions must be applied on the tissue dosimetry parameters in the treatment planings according to the tables of 3, 4, 5 and 6 in this study.

This technical report focuses on developing a do-it-yourself (DIY) model of a water phantom for training in ultrasound-guided needle insertion techniques. Ultrasound technology is becoming more widely used in perioperative and intensive care settings. However, accurate needle placement using ultrasound guidance necessitates strong spatial reasoning and hand-eye coordination. To address this, the authors experimented with a water phantom model that is cost-effective, easily accessible, and efficient for training. The DIY water phantom was made using materials such as an examination glove, a used vial rubber cap, water, adhesive tape, sealing glue, and a target object. This technical report discusses the process of assembling the water phantom and the potential benefits it offers for ultrasound training., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Anand et al.)

Introduction: 103Pd is a low energy source, which is used in brachytherapy. According to the standards of American Association of Physicists in Medicine, dosimetric parameters determination of brachytherapy sources before the clinical application was considered significantly important. Therfore, the present study aimed to compare the dosimetric parameters of the target source using the water phantom and soft tissue. Methods: According to the TG-43U1 protocol, the dosimetric parameters were compared around the 103Pd source in regard with water phantom with the density of 0.998 gr/cm3 and the soft tissue with the density of 1.04 gr/cm3 on the longitudinal and transverse axes using the MCNP4C code and the relative differences were compared between the both conditions. Results: The simulation results indicated that the dosimetric parameters depended on the radial dose function and the anisotropy function in the application of the water phantom instead of soft tissue up to a distance of 1.5 cm, between which a good consistency was observed. With increasing the distance, the difference increased, so as within 6 cm from the source, this difference increased to 4%. Conclusions: The results of the soft tissue phantom compared with those of the water phantom indicated 4% relative difference at a distance of 6 cm from the source. Therefore, the results of the water phantom with a maximum error of 4% can be used in practical applications instead of soft tissue. Moreover, the amount of differences obtained in each distance regarding using the soft tissue phantom could be corrected.

Purpose: Phantoms for horizontal beam geometry can avoid issues in vertical‐beam geometry, such as change in chamber depth due to evaporation, and defining the origin at the water surface. However, their thin entrance windows would deform when these phantoms are filled, which can change the chamber depth, as pointed out by The International Atomic Energy Agency (IAEA) TRS‐398. Currently, few reports (Arib et al., J Appl Clin Med Phys. 2006; 7:55–64, and Kinoshita et al., Rep Pract Oncol Radiother. 2018; 23:199–206) are available with practical data on window deformation. Therefore, we investigated the influence of entrance window deformation on chamber depths in water phantoms and the measurements in various beam modalities. Methods: To examine widely used phantoms and phantoms with different characteristics, three phantom types were investigated (the number of phantoms investigated appears in parentheses): PTW—type 41023 (2), Qualita—QWP‐04 (2), and IBA—WP34 (2). Prior to the investigation, these phantoms were stored for acclimatization in a room for approximately 10 h under the following two conditions: (a) room temperature: 21 ± 2°C; (b) room temperature: 27 ± 2°C. Using a dial indicator, the centers of the windows were monitored every 30 min for 12 h immediately after the phantoms were filled, in a treatment room at the room temperature of 21 ± 2°C. Results: Immediately after the phantoms were filled, the window deformation ranged from −0.07 (inward‐deformation) to 0.3 mm (outward deformation) among the six phantoms, in comparison with empty phantom windows. For 12 h after the phantoms were filled, the change in the deformation was up to 0.23 mm, but typically less than 0.15 mm. Conclusions: Reference dosimetry in photon, electron, and proton beams would not be influenced significantly by these window behaviors, whereas the window deformation has a slight impact on those heavy ion beams. [ABSTRACT FROM AUTHOR]

Bragg peak profiles are measured by the TV-type DTeT detector. Two-coordinate measurements for the region of energy release in a water phantom are carried out. An experiment with an additional water-filled extension during pulsed irradiation of the water phantom by a proton beam with an energy up to 260 MeV is performed. [ABSTRACT FROM AUTHOR]

The ways to improve operating characteristics of the TV-type proton detector related to the enhancement of the energy release emission brightness is studied. A working example of the proton detector with an extended energy range (depth—dose) from 30 to 207.5 MeV is fabricated. [ABSTRACT FROM AUTHOR]

The results on the improvement of the mathematical model for calculating the TV-type detector are presented. The parameters of the analytical formula valid for proton energies from 60 to 200 MeV, based on the combination of parabolic cylinder functions and consistent with numerical methods and new experimental data, are determined. [ABSTRACT FROM AUTHOR]

Purpose: Development of patient organ dose evaluation method in computed tomography (CT) needs to model the correlation between organ dose and patient size, under various conditions of scan length, tube current lineshape, and organ location. To facilitate this task, this work was to perform a comprehensive study of the relationship between the dose to water phantom and its diameter under various settings of phantom axis, scan length, and the location across or beyond the scanned range. Methods: A dose calculation algorithm and the published data by Li et al. [Med. Phys. 39, 5347–5352 (2012); 40, 031903 (2013); 43, 5878–5888 (2016)] were used to calculate longitudinal dose distribution DL(z) in 10‐ to 50‐cm diameter water phantoms undergoing constant tube current scans. The relationship between dose and phantom diameter was examined on three phantom axes (center, cross‐sectional average, periphery), at seven scan lengths from 15 to 70 cm, and at eight longitudinal locations within or beyond each scan range. The water phantom results were compared to those of patient models of eight previous studies. Results: For the water phantoms matching the abdominal perimeters (36.3–124.5 cm) of the GSF family of voxelized phantoms, the median and range of DL(z)(water) across scan range were consistent with those of the organ doses from the GSF phantom abdominal scans of a previous study. In 41 water phantoms (diameters 10–50 cm), DL(z)(water) at locations inside scan range decreased with increasing phantom diameters. Exponential regression analysis of the above trend yielded regression parameters approximately consistent with those of phantom or patient models of eight previous studies. However, the usual exponential function might not be optimal for modeling the dose dependence on subject size. Inside scan range, the log(dose) vs diameter curve was non‐linear on a semilogarithmic graph. Outside of scan range, dose might increase with larger subject sizes, contradicting to the exponential attenuation law. In the CT examinations of a patient population, direct modeling of organ dose dependence on patient size would be more challenging due to varying scan lengths and changing organ distances to the scan range centers. Conclusion: An efficient approach to take into account the abdominal organ dose dependences on other factors is to calculate DL(z)(water) with the water equivalent diameter, scan length, and tube current lineshape from the patient examinations, and to evaluate the organ dose to DL (z)(water) ratio, where z is at the organ's longitudinal location. The ratio may be used for abdominal organ dose evaluation in the patient examinations. How to make use of DL(z)(water) for organ dose evaluation in other body regions may be explored in the future. [ABSTRACT FROM AUTHOR]

Background Uncertainty in the calibration of high-energy radiation sources is dependent on user and equipment type. Aim We evaluated the uncertainty in the positioning of a cylindrical chamber at a reference depth for reference dosimetry of high-energy photon beams and the resulting uncertainty in the chamber readings for 6- and 10-MV photon beams. The aim was to investigate major contributions to the positioning uncertainty to reduce the uncertainty in calibration for external photon beam radiotherapy. Materials and methods The following phantoms were used: DoseView 1D, WP1D, 1D SCANNER, and QWP-07 as one-dimensional (1D) phantoms for a vertical-beam geometry; GRI-7632 as a phantom for a fixed waterproofing sleeve; and PTW type 41023 and QWP-04 as 1D phantoms for a horizontal-beam geometry. The uncertainties were analyzed as per the Guide to the Expression of Uncertainty in Measurement. Results The positioning and resultant uncertainties in chamber readings ranged from 0.22 to 0.35 mm and 0.12–0.25%, respectively, among the phantoms (using a coverage factor k = 1 in both cases). The major contributions to positioning uncertainty are: definition of the origin for phantoms among users for the 1D phantoms for a vertical-beam geometry, water level adjustment among users for the phantom for a fixed waterproofing sleeve, phantom window deformation, and non-water material of the window for the 1D phantoms for a horizontal-beam geometry. Conclusion The positioning and resultant uncertainties in chamber readings exhibited minor differences among the seven phantoms. The major components of these uncertainties differed among the phantom types investigated. [ABSTRACT FROM AUTHOR]

An experimental prototype of the television-type detector is developed, fabricated, and tested; its calibration capability is verified at the “Prometheus” proton accelerator; two-coordinate measurements of the energy release region in a water phantom are performed. The energy release region sizes are experimentally determined in the form of Bragg curves during pulsed irradiation of the water phantom with a proton beam with an energy from 65 to 192.5 MeV. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Physics is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background Peripheral or scatter dose harms neighbouring normal tissues during administration of dose to cancerous tissues, therefore, knowledge of peripheral dose is an important consideration in radiotherapy. Aim In present study, absorbed dose measurements in a water phantom were performed for three field sizes, 7 × 7 cm 2 , 10 × 10 cm 2 and 15 × 15 cm 2 . Materials and methods For each field size, dose was measured at six depths below the front surface of the water phantom; 2.5–15 cm with an interval of 2.5 cm. Measurements were made at equal transverse distances along the horizontal axis, from 1 cm to 6 cm, on both sides of the central beam axis and normalized with central axis dose of each field. All measurements were made at the source to surface distance of 100 cm. Results Variation of peripheral dose with lateral distance was analysed and an appropriate parametric equation for each field size and depth was constructed. Conclusions The peripheral radiation dose showed a strong dependence on field size and distance from field boundary. [ABSTRACT FROM AUTHOR]

Background: The use of magnetic resonance linear accelerators (MR-LINACs) for clinical treatment has opened up new possibilities and challenges in the field of radiation oncology. However, annual quality assurance (QA) is relatively understudied due to practical considerations. Thus, to overcome the difficulty of measuring the dose with a small water phantom for TRS-398 or TG-51 in all external beam radiation treatment unit environments, such as MR compatibility, we designed a remote phantom with a three-axis changeable capacity for QA., Methods: The designed water phantom was tested under an MR environment. The water phantom system comprised of three parts: a phantom box, a dose measurement tool, and a PMD401 drive system. The UNIDOSE universal dosimeter was used to collect beam data. The manufacturer's developer tools were utilized to position the measurement. To ensure magnetic field homogeneity, a distortion phantom was prepared using sixty fish oil capsules aligned radially to distinguish the oil and free air. The phantom was scanned in both the MR simulator and computed tomography (CT), and the acquired images were analyzed to determine the position shift., Results: The dimensions of the device are 30 cm in the X-axis, 20 cm in the Y-axis, and 17 cm in the Z-axis. Total cost of materials was no more than $10,000 US dollars. Our results indicate that the device can function normally in a regular 1.5 T MR environment without interference from the magnetic field. The water phantom's traveling speed was found to be approximately 5 mm/s with a position difference confined within 6 cm intervals during normal use. The distortion test results showed that the prepared MR environment has uniform magnetic field homogeneity., Conclusions: In this study, we constructed a prototype water phantom device that can function in an MR simulator without interference between the magnetic field and electronic components. Compared to other commercially available MR-LINAC water phantoms, our device offers a more cost-effective solution for routine monthly QA. It can shorten the duration of QA tests and relieve the burden on medical physicists., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-23-189/coif). The authors have no conflicts of interest to declare., (2023 Quantitative Imaging in Medicine and Surgery. All rights reserved.)

Protective properties of a material containing ferroboron and polyethylene are experimentally studied. The protection factors in the case of the interaction with fast neutron and gamma-ray fluxes emitted by a water phantom exposed to a proton beam with energies of 50, 100, and 130 MeV are determined. [ABSTRACT FROM AUTHOR]

In cancer therapy using gamma radiation one of the limiting factors in dose delivery is the safety of the healthy tissues and organs around the cancerous mass. Better collimation and dose fractionation are employed to achieve this. In the present paper results of scattered dose to healthy tissues around the incident beam cross-section or beam boundaries have been estimated using IAEA standard water phantom and Co-60 incident radiation. It has been observed that scattered dose to healthy tissues increases linearly from 4% to 7% of the incident dose of 185 cGy to 200 cGy at the centre of the beam, at 5 cm depth in water, as we increase the incident beam field size from 5 cm x 5 cm to 10 cm x 10 cm. Also the maximum unwanted scattered dose for any field size remains closer to the incident beam boundaries.

The design studies related to a prompt γ-rays in vivo neutron activation analysis facility are described. The designs were based on two neutron sources: 252Cf and 241Am-Be, four collimator materials: polyethylene, 5% boric-acid doped polyethylene, graphite, and the heavy water, two collimator shapes: pyramidal and rectangular, and two configurations: unilateral and bilateral. The aim of this work was improving the uniformity of the gamma production rate distribution with depth in a large biological sample. For the sample, a water phantom measuring 32cm x 16cm x 100cm was simulated. The simulations were performed by MCNPX 2.4.0 Monte Carlo code. This study recommends the prompt γ-rays IVNAA facility in the bilateral configuration with graphite as a collimator material and 241Am-Be as neutron source.

Introduction: 90 Sr/ 90 Y source has been used for the intravascular brachytherapy to prevent coronary restenosis in the patients who have undergone angioplasty. The aim of this research is to determine the dose distribution of 90 Sr/ 90 Y source in a water phantom. Materials and Methods: In the present work, MCNP code has been applied to calculate the dose distribution around a 3 cm length of 90 Sr/ 90 Y source in a 30×30×30 cm 3 water phantom. Also, the exact geometry of the source has been used in this simulation. Tally *F8:e which is suitable for beta ray dosimetry has been evaluated with less than %5 relative error in a sphere having 0.2 mm radius. Results: The isodose curve for 10, 20, 40, and 90% depth dose (PDD) were derived based on the calculated dose curves along the parallel and perpendicular axis to the source. Discussion and Conclusion: The results obtained in this work are in a good agreement with the experimental result published by Buckley et al. and the International Atomic Energy Agency (IAEA) report in a water phantom. Therefore, the result of this research can be used in the intravascular brachytherapy.

An apparatus for visualizing the energy release region in a water phantom is developed and tested on the proton beam of the radiotherapeutic accelerator. The shape and sizes of the emission region during pulsed irradiation of the phantom with the proton beam is experimentally determined in the form of Bragg curves. The results are compared with model calculations. [ABSTRACT FROM AUTHOR]

Double-differential neutron yields from a water phantom bombarded with 290-MeV/nucleon and 430-MeV/nucleon carbon ions were measured at emission angles of 15°, 30°, 45°, 60°, 75°, and 90°, and angular distributions of neutron yields and doses around the phantom were obtained. The experimental data were compared with results of the Monte-Carlo simulation code PHITS. The PHITS results showed good agreement with the measured data. On the basis of the PHITS simulation, we estimated the angular distributions of neutron yields and doses from 0° to 180° including thermal neutrons. [ABSTRACT FROM AUTHOR]

A detector with a highly sensitive television camera for visualizing the absorbed dose formation region in a water phantom is developed and tested at the electron beam of the 'Pakhra' accelerator. The detector consists of a water phantom and a television camera with equipment for picking-up information from it. The geometrical shape and sizes of the luminosity region in the phantom exposed to a pulsed electron beam with an energy of 7 MeV are determined. Model calculations for determining absorbed doses upon electron absorption in water are performed. [ABSTRACT FROM AUTHOR]

Copyright of Zeitschrift für Medizinische Physik is the property of Elsevier GmbH, Urban & Fischer Verlag and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this report, we applied diffusion tensor imaging (DTI) methods in 36 patients with uncomplicated mild traumatic brain injury (mTBI) and a comparison group of 37 participants with orthopedic injury. Our aim was to characterize regional and global macro- and microstructural attributes of white matter (WM), gray matter (GM), in addition to volume and diffusivity of cerebrospinal fluid (CSF) to identify and differentiate patterns of acute and short-term recovery. Given that previous DTI reports on mTBI in adults using a region-of-interest approach implicated the corona radiata (CR), corpus callosum, and hippocampus, we analyzed and quantified DTI metrics of these regions using atlas-based methods. The normalized volume percentages of global CSF, GM, and WM were not different between the mTBI and orthopedic comparison (OC) groups at either the baseline or follow-up time points or between the baseline and follow-up time points within the OC group ( p>0.17; uncorrected for multiple comparisons). The DTI metrics did not differ between groups at either occasion. However, an increase was noted on follow-up in the OC group in the global mean diffusivity of GM (uncorrected p=0.003) and WM (uncorrected p=0.02), indicating a decrease in diffusivity at the 3-month postinjury, as compared to the baseline scan. An analysis of the DTI data collected longitudinally in the CR show insignificant changes in the OC group ( p>0.08; N=37). CR radial diffusivity was found to be elevated in the between-group comparison at baseline (mTBI1 vs. OC1), but did not differ in the within-group comparison (mTBI1 vs. mTBI2; N=19), suggesting the possible resolution of edema. Our analysis of the cross-sectional and follow-up data, which is uncorrected for multiple comparisons, demonstrates dissociation between volumetric (macrostructural) and tissue integrity (microstructural) attributes and shows the potential utility of DTI to capture transient edema in the CR. [ABSTRACT FROM AUTHOR]