Surgical procedures involving the use of x-rays in the operating room (OR) have increased in recent years, thereby increasing the exposure of OR staff to ionizing radiation. An individual dosimeter makes it possible to record the radiation exposure to which these personnel are exposed, but there is a lack of compliance in the wearing of these dosimeters for several practical reasons. This makes the dose results obtained unreliable. To try to improve the rate of dosimeter wearing in the OR, the Dosibadge project studied the association of the individual dosimeter with the hospital access badge, forming the Dosibadge. Through a study performed at the Tours University Hospital in eight different ORs for two consecutive periods of 3 months. The results show a significant increase in the systematic use of the dosimeter thanks to the Dosibadge, which improves the reliability of the doses obtained on the dosimeters and the monitoring of personnel. The increase is especially marked with clinicians. Following these results and the very positive feedback to this first single-centre study, we are then planning a second multicentre study to validate our proof of concept on different sites, with the three brands of individual dosimeters used in France i.e. dosimeters supplied by Dosilab; Landauer and IRSN.

This work aims to improve the post stabilty of reusable potassium iodide hydrogel dosimter. A reusable and low-cost radiochromic dosimeter containing a gel matrix of polyvinyl alcohol, potassium iodide dye, froctose as reducing agent and glutaraldehyde as cross-linking agent was developed for dose calibration in radiotherapy. The gel samples were exposed to different absorbed doses using a medical linear acceleration. UV-vis Spectrophotometry was utilized to investigate the changes in optical-properties of irradiated gels with regard to peak wavelength of 353 nm. The stability of the gel (one of the most limitation of using this dosimeter) was improved significantly by the addition of certain concentrations of dimethyl sulfoxide. The two-dimensional optical imaging system of charge-coupled-device (CCD) camera with a uniform RGB light-emitting-diode (LED) array source was used for diffusion coefficient purpose using two dimensional gel template. The value of diffusion coefficient reported is significant and highly reduced compared with other dosimeters reported in the literatures. Moreover, heating the improved gels to certain temperatures results in resetting their optical properties, which makes it possible to reuse for multiple times.

UNASSIGNED: The aim of this study was to evaluate the influence of different cone-beam computed tomography (CBCT) acquisition protocols on reducing the effective radiation dose while maintaining image quality.
UNASSIGNED: The effective dose emitted by a CBCT device was calculated using thermoluminescent dosimeters placed in a Rando Alderson phantom. Image quality was assessed by 3 experienced evaluators. The relationship between image quality and confidence was evaluated using the Fisher exact test, and the agreement among raters was assessed using the kappa test. Multiple linear regression analysis was performed to investigate whether the technical parameters could predict the effective dose. P-values<0.05 were considered to indicate statistical significance.
UNASSIGNED: The optimized protocol (3 mA, 99 kVp, and 450 projection images) demonstrated good image quality and a lower effective dose for radiation-sensitive organs. Image quality and confidence had consistent values for all structures (P<0.05). Multiple linear regression analysis resulted in a statistically significant model. The milliamperage (b=0.504; t=3.406; P=0.027), kilovoltage peak (b=0.589; t=3.979; P=0.016) and number of projection images (b=0.557; t=3.762; P=0.020) were predictors of the effective dose.
UNASSIGNED: Optimized CBCT acquisition protocols can significantly reduce the effective radiation dose while maintaining acceptable image quality by adjusting the milliamperage and projection images.

BACKGROUND: A new quality assurance and control method for electrometers using a new current source, different from the method published in the guidelines for electrometers, has been reported. This current source uses dry batteries and exhibits excellent performance in terms of voltage, temperature, and time characteristics. The electrometer sensitivity coefficient can be calculated by comparing the sensitivity of one electrometer with that of another on the electrometer calibration coefficient that has been calibrated by a calibration laboratory in advance in both methods. The guideline method requires two or more sets of ionization chambers and electrometers in the facility. In contrast, our method does not use ionization chambers; therefore, the sensitivity ratio of the electrometer can be measured in any facility. This study compared the uncertainty of the electrometer sensitivity factor calculated using the new current source method (current method) with that calculated using a linear accelerator (LINAC) and ionization chambers (LINAC method) described in the electrometer guidelines.
METHODS: In this study, we used a current source that we invented previously by Kawaguchi Electric Works in Japan. The sensitivity ratios of the electrometers were measured with three manufacture\'s electrometers. The electrometer sensitivity factor was calculated by multiplying the electrometer calibration coefficient. The ionization chamber was 30013 (PTW), and the current source was the current obtained from 10 MV TrueBeam X-rays under calibration conditions. The mean value, standard deviation, and coefficient of variation were calculated. The time required to set up the ionization chamber for calculating the sensitivity ratio of the electrometer was also measured. The accuracy was confirmed by calculating the expanded uncertainty of the electrometer sensitivity coefficients.
RESULTS: The LINAC method had a maximum coefficient of variation of 0.072%. The gross time of the LINAC method was approximately 110 min. The current method had a maximum coefficient of variation of 0.0055% and took less than half the time taken by the LINAC method (35 min) because there was no waiting time for the ionization chamber to be set up and the applied voltage to stabilize under calibration conditions. The expanded uncertainties of the electrometer calibration coefficients were 0.36% and 0.36%, respectively.
CONCLUSIONS: The new cross-comparison method for electrometer sensitivity factors using a current source is more efficient and useful than the linear accelerator method described in the guidelines; furthermore, this method ensured accuracy for quality assurance and control of electrometers.

This work describes the development of a reusable 2D detector based on radiochromic reaction for radiotherapy dosimetric measurements. It consists of a radiochromic gel dosimeter in a cuboidal plastic container, scanning with a flatbed scanner, and data processing using a dedicated software package. This tool is assessed using the example of the application of the coincidence test of radiation and mechanical isocenters for a medical accelerator. The following were examined: scanning repeatability and image homogeneity, the impact of image processing on data processing in coincidence tests, and irradiation conditions-monitor units per radiation beam and irradiation field are selected. Optimal conditions for carrying out the test are chosen: (i) the multi-leaf collimator gap should preferably be 5 mm for 2D star shot irradiation, (ii) it is recommended to apply ≥2500-≤5000 MU per beam to obtain a strong signal enabling easy data processing, (iii) Mean filter can be applied to the images to improve calculations. An approach to dosimeter reuse with the goal of reducing costs is presented; the number of reuses is related to the MUs per beam, which, in this study, is about 5-57 for 30,000-2500 MU per beam (four fields). The proposed reusable system was successfully applied to the coincidence tests, confirming its suitability as a new potential quality assurance tool in radiotherapy.

The effect of mammography measurement conditions was investigated to evaluate their impact on measurement uncertainties in clinical practice. The most prominent physical X-ray beam quantities i.e., - air kerma, half-value layer, and X-ray tube voltage - were examined by measuring the response of two ionization chambers and six X-ray multimeters (XMMs) of different models. Measurements were performed using several anode/filter combinations and both with and without the compression paddle in the X-ray beam. Maximum differences of higher than 6 % were found for all quantities when the dosimeter displayed value was compared with the reference value or the variation within the clinical anode/filter combinations Mo/Mo and Mo/Rh were considered. The study showed that the calibration procedure with the W/Al anode/filter combination was reliable only for ionization chambers, and the response of XMMs varies in such a way that the calibration coefficient cannot be predicted between various measurement conditions used in calibration and clinical practices. XMM calibrations are typically performed without a compression paddle in the beam, and the response of the XMM changes when radiation quality is slightly altered. If XMM specific data is not available, based on this study, an additional uncertainty of 2 % (k = 1) could be used as a typical estimate, at least for air kerma measurements. XMMs should be used for clinical measurements in mammography only with correct settings. If the correct settings are not available, the XMMs should not be used or used only with extreme caution.

The metrological quality of a measurement is characterised by evaluating the uncertainty in the measurement. In this paper, uncertainty in personal dose measured using individual monitoring CaSO4:Dy-based thermoluminescence dosimeter badge is evaluated by application of the guide to the expression of uncertainty in measurement method. The present dose reporting quantity, whole body dose (WBD) and the proposed quantity, personal dose equivalent, Hp(10) has been used as measurands. The influence of various input quantities on the measurement were analyzed through tests that conform to the requirements of the International Electrotechnical Commission IEC 62387. The study found that the expanded uncertainties for WBD and Hp(10) measurements were 63.4% and 41.4%, respectively, corresponding to a 95% coverage probability for workplace fields covering a wide photon energy range (33-1250 keV). However, the uncertainty estimates were quite lower for the type of workplaces that are identified using the dose evaluation algorithm. The input quantities, namely, the response to a mixture of photon beam qualities and photon energy and angular dependence contribute the most to the total uncertainty.

We quantified the level of backscatter radiation generated from physicians\' heads using a phantom. We also evaluated the shielding rate of the protective eyewear and optimal placement of the eye-dedicated dosimeter (skin surface or behind the Pb-eyewear). We performed diagnostic X-rays of two head phantoms: Styrofoam (negligible backscatter radiation) and anthropomorphic (included backscatter radiation). Radiophotoluminescence glass dosimeters were used to measure the eye-lens dose, with or without 0.07-mm Pb-equivalent protective eyewear. We used tube voltages of 50, 65 and 80 kV because the scattered radiation has a lower mean energy than the primary X-ray beam. The backscatter radiation accounted for 17.3-22.3% of the eye-lens dose, with the percentage increasing with increasing tube voltage. Furthermore, the shielding rate of the protective eyewear was overestimated, and the eye-lens dose was underestimated when the eye-dedicated dosimeter was placed behind the protective eyewear. We quantified the backscatter radiation generated from physicians\' heads. To account for the effect of backscatter radiation, an anthropomorphic, rather than Styrofoam, phantom should be used. Close contact of the dosimeter with the skin surface is essential for accurate evaluation of backscatter radiation from physician\'s own heads. To assess the eye-lens dose accurately, the dosimeter should be placed near the eye. If the dosimeter is placed behind the lens of the protective eyewear, we recommend using a backscatter radiation calibration factor of 1.2-1.3.

This work builds upon a prior study, examining the dosimetric utility of pencil lead and thin graphitic sheets, focusing upon the measurement of skin doses within the mammographic regime. In recognizing the near soft-tissue equivalence of graphite and the earlier-observed favourable thermoluminescence yield of thin sheets of graphite, this has led to present study of 50 μm thick graphite for parameters typical of external beam fractionated radiotherapy and skin dose evaluations. The graphite layers were annealed and then stacked to form an assembly of 0.5 mm nominal thickness. Using a 6 MV photon beam and delivering doses from 2- to 60 Gy, irradiations were conducted, the assembly first forming a superficial layer to a solid water phantom and subsequently underlying a 1.5 cm bolus, seeking to circumvent the build-up to electronic equilibrium for skin treatments. Investigations were made of several dosimetric properties arising from the thermoluminescence yield of the 50 μm thick graphite slabs, in particular proportionality and sensitivity to dose. The results show excellent sensitivity within the dose range of interest, the thermoluminescence response varying with increasing depth through the stacked graphite layers, obtaining a coefficient of determination of 90%. Acknowledging there to be considerable challenge in accurately matching skin thickness with dose, the graphite sheets have nevertheless shown considerable promise as dosimeters of skin, sensitive in determination of dose from the surface of the graphite through to sub-dermal depth thicknesses.

BACKGROUND: Radiation dose measurement is an essential part of radiotherapy to verify the correct delivery of doses to patients and ensure patient safety. Recent advancements in radiotherapy technology have highlighted the need for fast and precise dosimeters. Technologies like FLASH radiotherapy and magnetic-resonance linear accelerators (MR-LINAC) demand dosimeters that can meet their unique requirements. One promising solution is the plastic scintillator-based dosimeter with high spatial resolution and real-time dose output. This study explores the feasibility of using the LuSy dosimeter, an in-house developed plastic scintillator dosimeter for dose verification across various radiotherapy techniques, including conformal radiotherapy (CRT), intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT), and stereotactic radiosurgery (SRS).
METHODS: A new dosimetry system, comprising a new plastic scintillator as the sensing material, was developed and characterized for radiotherapy beams. Treatment plans were created for conformal radiotherapy, IMRT, VMAT, and SRS and delivered to a phantom. LuSy dosimeter was used to measure the delivered dose for each plan on the surface of the phantom and inside the target volumes. Then, LuSy measurements were compared against an ionization chamber, MOSFET dosimeter, radiochromic films, and dose calculated using the treatment planning system (TPS).
RESULTS: For CRT, surface dose measurement by LuSy dosimeter showed a deviation of -5.5% and -5.4% for breast and abdomen treatment from the TPS, respectively. When measuring inside the target volume for IMRT, VMAT, and SRS, the LuSy dosimeter produced a mean deviation of -3.0% from the TPS. Surface dose measurement resulted in higher TPS discrepancies where the deviations for IMRT, VMAT, and SRS were -2.0%, -19.5%, and 16.1%, respectively.
CONCLUSIONS: The LuSy dosimeter was feasible for measuring radiotherapy doses for various treatment techniques. Treatment delivery verification enables early error detection, allowing for safe treatment delivery for radiotherapy patients.