Entrance Surface Dose Research Articles

Evaluation of radiation dose and cancer risk for paediatric digital radiography in a Moroccan hospital

Pediatric radiography is the first line of most diagnostic examinations and an effective tool that provides important information about the patient's health status.This study aims to investigate the Entrance Surface Dose (ESD) and organ doses for pediatric patients undergoing imaging procedures of the abdomen, chest, pelvis, and nasopharynx using Optically Stimulated Luminescence Dosimeters OSLDs and an anthropomorphic phantom.An ATOM pediatric 5-year-old phantom was imaged using a Digital Radiography (DR) based on similar conditions of routine radiography (exposure parameters kVp, mAs, SID: Source Image receptor Distance). The OSLDs were inserted at the appropriate sites to measure localized doses in the sensitive organs.The results showed that the entrance surface doses for the pediatric patients were 0.17 ± 0.03 mGy, 0.10 ± 0.00 mGy, 0.46 ± 0.00 mGy, and 0.42 ± 0.02 mGy, respectively, for the abdomen (AP), chest (AP), pelvis (AP), and nasopharynx (LAT). The range of organ doses were 0.05–0.45 mGy, 0.01–0.44 mGy, 0.13–1.05 mGy, and 0.084–0.99 mGy for the abdomen, chest, pelvis, and nasopharynx examination, respectively. Effective doses (ED) were 0.088 ± 0.021 mSv, 0.011 ± 0.004 mSv, 0.058 ± 0.007 mSv, and 0.044 ± 0.024 mSv for the abdomen, chest, pelvis, and nasopharynx examination, respectively.The likelihood of cancer, as determined by the ICRP health risk model with a rate of 500 cases per 10 000 person-Sv (5% per sievert), estimated that a 0.015 case of health risk (0.3 person-Sv × 5% per sievert) may in the future be attributable to four X-ray pediatric procedures conducted in 2022.The ESD, ED, and organ dose values are deemed acceptable compared to those reported in the literature. Although the risk of incidence and mortality from cancer during life is minimal, it should not be ignored.

Effects of Different Fields of View and Rotation Angles on Radiation Doses to Highly Radiosensitive Organs in Children Using Dental Cone Beam Computed Tomography

Dental cone beam computed tomography (CBCT) is a diverse 3D X-ray imaging technique that has enabled clear visualization of the teeth and surrounding structures. The most common diagnostic purpose of dental CBCT examination in children is ectopic eruption and impacted teeth, and a small field of view (FOV) is often used. Since it is difficult for children to control their body movements, reducing the rotation angle is effective. However, no studies have examined the effects of different rotation angles on radiation doses to highly radiosensitive organs in children using small FOVs. The purpose of this study was to examine the effects of small FOVs (4 × 4 cm and 6 × 6 cm) and rotation angles (360° and 180°) on doses that highly sensitize organs in children using dental CBCT. The entrance surface doses to lenses, thyroid lobes, parotid glands, and sublingual glands of a pediatric whole-body phantom were measured. By reducing the FOV from 6 × 6 cm to 4 × 4 cm, the dose to the sublingual gland could be significantly decreased. Additionally, by reducing the rotation angle from 360° to 180°, the lens dose can be decreased significantly. As the rate of dose reduction varies among organs, it is important to consider the relative positions of different organs with respect to the FOV and the trajectory of the X-ray tube.

Factors Influencing ESD in NICUs and Adult Chest X-ray Examination in Bangladesh

Understanding the factors that influence Entrance Surface Dose (ESD) in neonatal and adult chest X-ray examinations is crucial for improving radiation safety. This study explores these influences, along with patterns in chest X-ray usage in Bangladesh, highlighting demographic trends, symptoms, and diagnostic outcomes. Conducted in a single hospital in Dhaka, the study assessed radiation doses in 150 adults and 150 neonates. Data collection involved using a 1000 mA X-ray machine for adults (aged 11-80 years) and a portable Medion MI 100 MOVX Mobile X-ray Machine for neonates (aged 1-20 days), with participants chosen through simple random sampling. X-ray exposure parameters (kVp and mAs) were recorded, and ESD (measured in milligrays) was calculated using a formula tailored for adults and neonates. The results showed a higher number of males (57.3%) than females (42.7%) seeking X-rays. The most common symptoms were fever (51.3%), cold and cough (32%), and chest pain (13.3%). Pulmonary inflammatory lesions were observed in 13.3% of cases, with pleural effusion and cardiomegaly present in 8% and 6.7% of patients, respectively, while 72% had normal findings. There was a noticeable link between certain symptoms and diagnoses, such as chest pain correlating with cardiomegaly and fever with pulmonary inflammatory lesions. ESD levels generally increased with age, though there was a slight decrease in the 51-60 age group. These findings provide valuable insights into chest X-ray practices, which could guide better patient care and targeted interventions in Bangladesh.

Evaluation of the performance of digital x-ray systems in pelvis radiography

The aim of this study was to investigate the performance of eight digital radiography systems and to optimise the dose-image quality relationship for digital pelvis radiography. The study involved eight digital radiography systems used for general examinations at Vilnius University Hospital Santaros Klinikos. An anthropomorphic pelvic phantom (CIRS, US) was used to simulate a patient undergoing clinical pelvis radiography. Dose quantities entrance surface dose, dose area product (DAP) and exposure parameters (kVp, mA, mAs) were measured and the effects on the images were evaluated, considering physical contrast to noise ratio (CNR) and observer-based evaluations as image quality metrics. Increasing the tube voltage by 5 kVp from standard protocol led to a reduction in radiation dose (DAP) by 12%–20% with a slight impact on image quality (CNR decreases by 2%–10%). There was an inter-observer variability in image rating across different equipment (kappa value between 0 and 0.3); however, both observers agreed that increasing kVp up to 85–90 kV had no effect on perceived image quality. The results indicate that optimisation strategies should be tailored specifically for each x-ray system since significant performance differences and wide variations in radiation dose exist across various digital radiography systems used in clinical settings. The use of high kVp can be used for dose optimisation in digital pelvis radiography without compromising image diagnostic accuracy.

Assessment of radiation dose received from knee joint X-ray examinations

BackgroundMedical exposure from diagnostic X-ray machines represents the primary artificial source of human exposure to low ionizing radiation. Knee X-rays are a standard examination to diagnose multiple conditions ranging from traumatic injuries, degeneration, and cancer. In Saudi Arabia, there is a lack of available data and pertinent information regarding the assessment of the patient entrance surface dose (ESD) from knee X-rays. This study aims to estimate the ESD for adult patients undergoing knee X-ray examinations at four major medical centres in Saudi Arabia. Methods and materialsThe ESD was estimated indirectly using X-ray exposure factors for patients and directly using optically stimulated luminescence (OSL). The results were compared with previous studies conducted nationally and internationally and with international reference levels. ResultsThe results of this research showed that the mean patient ESD was 1.4 ± 0.37 mGy using the direct method and 1.12 ± 0.20 mGy using the indirect method. The estimated mean ESD values were found to be much higher than the mean ESD reference values, emphasizing the crucial requirement for optimizing radiation doses in conventional radiology to improve patient safety and diagnostic effectiveness. ConclusionThis confirms the requirement for reducing patients’ doses to the tolerable levels recommended by many international radiation protection commissions.

Patients' dosimetry during lumbar radiographic examination (Lat) in certain hospitals at Dhi Qar governorate, Iraq

The work is aimed at investigating the entrance surface dose (ESD) for adult patients undertaking routine lumbar X-ray examination, and therefore ensure that the patients receive no excessive radiation dose during this radiography. This study was conducted at 4 selected hospitals: Al-Hussein Teaching Hospital (AHTH), Al-Nasiriyah Teaching Hospital (ANTH), Al-Haboubi Teaching Hospital (AHTH) and Souq Al-Shuyoukh General Hospital (SASGH) in Dhi Qar, Iraq. The ESD was calculated for 102 adult patients who underwent X-ray examinations of the lumbar spine using the physical parameters (i.e. Tube voltage-kVp, Tube loading- mAs and distance between X-ray tube and detector- SID) from all considered X-ray units, as well as on the X-ray tube output that was measured using an ionization chamber (Rad-Check Plus). The enrolled patients also had their demographic information recorded (gender, weight and height). The finding demonstrated that the average ESD values were (4.886, 4.288, 6.047, 6.378, 5.949, 9.322, 12.731, 4.094) mGy for AHTH1, AHTH2, AHTH3, ANTH1, ANTH2, ANTH3, AHTH, SASGH, respectively. The ESD values were seen to be comparable with internationally recognized sources UNSCEAR 2010, UK 2012, EC, and IAEA and with previously published studies such as those in Sudan 2014, Iran 2020, Nigeria 2019, and Ghana 2023. Finally, further studies must be carried out, and the relevant institutions must conduct continuous training courses for radiographers to ensure that the radiation dose is within the recommended level.

A survey on mean glandular dose in mammography examination and the factors affecting it in Shahid Sadoughi Hospital, Yazd, Iran.

mammography is the gold standard in the early detection of breast cancer. Due to the increase in the rate of women suffering from this malignancy all over the world, this imaging modality has been widely used. Considering the side effects caused by ionizing radiation to measure the carcinogenic risk of mammography X-rays, mean glandular dose (MGD) is the best parameter to evaluate the dose received by patients undergoing mammography. The aims of this study were to measure MGD in mammography in mammographic craniocaudal (CC) and mediolateral oblique (MLO) projections and investigate the relationship of MGD with compressed breast thickness (CBT), body mass index, age of the patient, and device exposure conditions. this cross-sectional analytical study was conducted on women aged 30-70 referring to the mammography unit of Shahid Sadoughi Hospital in Yazd city from May to August 2022. The TLD-GR 200 (thermoluminescence dosimeter) was placed on the breast of the patients for CC and MLO projections, and then the MGD was obtained by multiplying the entrance surface dose and the normalized glandular dose. Analysis of data (such as demographic information of patients, CBT, kVp, and mAs) was done by SPSS 23 software. The normality of the data was checked using Shapiro-Wilk tests. It was found that except for age, other variables did not have a normal distribution; therefore, equivalent parametric and nonparametric tests were used. In this regard, Spearman's correlation was used to assess the correlation between variables. P-value < .05 was considered as level of significance. The mean±standard deviation (SD) age of patients was 47.3±7.1years. The median±IQR (the interquartile range (IQR) is a measure of statistical dispersion, which is the spread of the data. It is defined as the difference between the 75th and 25th percentiles of the data.) (mean±SD) value of MGD per woman was 1.2±0.4mGy (1.3±0.3mGy). The median±IQR MGD in the MLO and CC projections was 1.6±0.6mGy and 0.9±0.4mGy, respectively. Significant relationships (P-value ≤ .001) were observed between MGD with CBT (R=0.62) and age (R=-0.85). The results showed that the mammography unit at Shahid Sadoughi Hospital in Yazd is functioning properly. The calculated median±IQR MGD per woman referring to this unit (1.2±0.4mGy) was clearly below the dose limit recommended by American College of Radiology and International Commission on Radiological Protection (3mGy). Moreover, among the factors affecting MGD, the highest correlation was seen between MGD and age (R=-0.85).

Carbon ion mono-energetic and spread-out Bragg peak measurements using nanocomposite Fricke gel dosimeters with LET-independent response

This study investigates the LET-dependence of dose measurements performed with a nanocomposite Fricke gel (NC-FG) upon irradiation with carbon ion beams to address the problem of quenching of gel dosimeters in high-LET particle therapy. The preparation of the NC-FG in a simple gel preparation device was performed for atmospheric and anoxic environmental conditions and two different container materials. Irradiation was performed with carbon ion beams at energies of 133.39MeV/u or 194.87MeV/u, complemented by a modulated 10 mm carbon ion spread-out Bragg peak (SOBP) irradiation. The R1 profiles obtained from the MRI readout were compared to the treatment planning system and a 2D-ionisation chamber array measurement performed for the mono-energetic and SOBP irradiations, respectively. For different dose levels, no difference in the gel response was obtained for the 3D-printed plastic containers, while the glass vials exhibited a linear dose response. Additional use of the glove box changes produced similar results. For both the mono-energetic and the SOBP irradiation, a linear dose response without quenching was observed. For depths ranging up to the Bragg peak position, the mono-energetic profiles deviated by less than ±15% from the planned dose distribution, excluding the lowest entrance surface dose (ESD). For the SOBP profiles, the deviation from the measured dose distribution was less than ±10% for depths between 20 mm and 33 mm. This study presents a LET-independent measurement of mono-energetic carbon ion Bragg peaks and, for the first time, a LET-independent measurement of a carbon ion SOBP with the NC-FG prepared in a simple gel preparation device under atmospheric conditions. The NC-FG provides a possible solution for 3D dosimetry in carbon ion radiotherapy.

Evaluation of the mean glandular dose (MGD) for phantoms with different glandularity/adipose tissue ratios using MgB4O7:Dy,Na dosimeters in mammography

This study focuses on the use of MgB4O7:Dy,Na dosimeters in mammography measurements. The reproducibility measurement and dose-response curves were studied for the characterization of dosimeters. Next, variation in entrance surface dose (ESD) and mean glandular dose (MGD) was investigated according to different glandularity/adipose tissue ratios of 30%/70%, 50%/50% and 70%/30% for fixed anode and variable filter combinations (Mo/Mo, Mo/Rh) using BR-12 phantoms with thicknesses from 2 to 6 cm. The ESD and MGD values increased at varying rates with increasing phantom thicknesses and glandularity ratios. The increase rate in MGD is ∼30% for both Mo/Mo and Mo/Rh for the difference between (70%/30%) and (50%/50%), considering the thickness of 6 cm. On the other hand, the MGD value obtained for a glandular ratio of 70%/30% at 6 cm for Mo/Mo is ∼40% higher than that for Mo/Rh. A proportional comparison of MGD differences obtained according to glandularity and filter changes may provide valuable contributions to the literature. Within this study, it was shown that MgB4O7:Dy,Na dosimeters can be used as new alternative dosimeters in the field of mammography to perform ESD and MGD measurements. In further studies, MgB4O7:Dy,Na dosimeters can be used to determine the various organ doses, such as eye and thyroid, resulting from the scattered radiation dose using rando phantoms.

Evaluating delivered radiation dose in intraoperative radiotherapy for breast cancer using TLD

The extra radiation that it delivers has been questioned by patients, physicians, and the public for early breast cancer patients of intraoperative radiotherapy (IORT). This investigation concerns a left breast Rando phantom with a lumpectomy cavity of 30 cm3 of left breast of Rando phantom made of polymethylmethacrylate (PMMA). Thermoluminescent dosimetry (TLD) was used to evaluate the extra radiation dose or air kerma (kair) rate under IORT from 20 Gy, 50 kV of an Xoft Axxent system. TLDs were first calibrated using 50 kV photons, and then inserted at phantom positions that were close to the positions of the represented organs and tissues. Equivalent doses (DT) delivered to the organ at risks (OAR) were evaluated according to ICRP 103. Entrance surface doses (ESD) or skin doses (Dskin) varied markedly among positions close to the lumpectomy cavity. The dose was 20 Gy at the surface of a balloon applicator and kair varied from 6.40 ± 0.92 Gy down to 1.20 ± 0.30 mGy along the left-right axis of the 17th slice of Rando. These experimental results are compared with those in the literature. The shielding effect of the tungsten-impregnated rubber was also evaluated. This study supports recommendations to patients, relatives, physicians and radiologists concerning IORT.

Estudio comparativo de la dosis de radiación de la mamografía espectral con contraste (CEM), mamografía digital y tomosíntesis mamaria

IntroductionThe use of contrast-enhanced spectral mammography (CESM) has increased in recent years, as has awareness of radiation dose safety among professionals and patients. The principal aim of this study was to compare radiation exposure measured using the entrance surface dose (ESD) and the average glandular dose (AGD) in CESM, full-field digital mammography (FFDM) and digital breast tomosynthesis (DBT). Our second objective was to evaluate differences caused by compressed breast thickness, compression force and patient age. Material and methodsA retrospective observational study included all patients who had undergone a CESM between May 2021 and May 2022. Data was collected on ESD and AGD from the different CESM studies, and breast density and volume were determined by 2expert radiologists. The comparative analysis focused on the dose of radiation received during the craniocaudal (CC) projection of the right breast in CESM studies and FFDM or DBT, performed within a 12-month period. Lastly, a statistical analysis was performed to determine the influence of breast compression thickness, compression force and patient age. ResultsSeventy-seven patients participated in the comparative study and forty-four in the dosimetric study. Differences in radiation dose (ESD/AGD) were found among the 3breast imaging techniques. The dose in CESM (1.70/5.39 mGy) was lower than in DBT (2.19/6.79 mGy) and higher than in FFDM (1.26/4.06 mGy) for an average breast compression thickness of 59.64mm. A positive correlation was observed between the dose received in CESM and breast compression thickness (ρ=0.55), and a negative correlation was observed with patient age (ρ= –0.27). No differences in dosimetric variables were observed for different compression forces. ConclusionsThe ESD and AGD in the CC projection of the right breast in CESM are higher than in FFDM but lower than in DBT. The dose had a positive correlation with breast compression thickness and a negative correlation with patient age.

Usefulness of Copper Filter Addition and Potential for Dose Reduction in Hip-joint Radiography

In this study, we evaluated image quality and radiation dose reduction when a Copper (Cu) filter was added to hip joint X-ray imaging. We measured effective energy without (0 mm) and with (0.1/0.2 mm) Cu-added filter at 70 kV, and we calculated soft tissue-bone contrast and signal-difference-to-noise-ratio (SDNR) under constant entrance surface dose. After that, we estimated the dose reduction rate. The effective energy was 32.07 keV for 0 mm Cu, 37.59 keV for 0.1 mm Cu, and 40.91 keV for 0.2 mm Cu. As the thickness of the Cu-added filter was increased, contrast decreased, but SDNR increased. The dose reduction rate in bone calculated measuring SDNR was 34% for 0.1 mm Cu and 47% for 0.2 mm Cu in max. It was suggested that adding Cu filter to hip-joint X-ray imaging could reduce entrance surface dose while maintaining the image quality based on SDNR.

Gridless adult cervical spine radiography and its' effect on image quality and radiation dose: A phantom study

IntroductionImaging of the cervical spine in general radiography is most frequently performed using an anti-scatter grid. The purpose of this study was to investigate the effects of a gridless setting on image quality and radiation dose during digital radiography of the anteroposterior (AP) and lateral (LAT) cervical spine. MethodsA phantom study was performed with a variety of tube voltages (63–75 kV) with and without an anti-scatter grid. The tube current time product (mAs) and dose area product (DAP) were recorded and used to calculate effective dose (ED) and individual organ dose using PCXMC 2.0 software, as well as entrance surface dose (ESD) and objective image quality: signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Subjective visual image quality grading characteristics (VGC) was performed by five qualified radiographers. ResultsIn a gridless setting, the AP and LAT positions showed significantly lower DAP (1.6 μGym2; 61.3 % and 1.6 μGym2; 51.2%), ESD (27.6 μGy; 57.3% and 77.2 μGy; 47.2%) and ED (4.2 μSv; 61.3% and 2.3 μSv; 48.9%). In a gridless setting in the AP position, there is a slight significant deterioration in image quality. In the lateral projection, on the other hand, the image quality without the use of grid was only significantly reduced in three of six criteria and there was no difference in the objective image quality between the two settings examined. ConclusionThe results of this study show that gridless setting significantly decreases radiation dose and image quality, but the quality in the lateral projection is still acceptable for diagnostic purpose. Implications for practiceThe protocol without the use of the anti-scatter grid in cervical spine radiography leads to a reduction in the radiation dose in both projections, but the image quality in the AP is significantly reduced for all criteria examined, with a slight deterioration in image quality in the lateral projection.

Analisa Pengukuran Entrance Surface Dose (ESD) Menggunakan Optically Stimulated Luminescence Dosimeter (OSLD) Pada Pasien Anak

The surface dose of radiation in conventional diagnostic radiology exams, also known as the entrance surface dose (ESD), is measured to ensure optimal radiation protection for patients. This study aimed to determine and analyze the doses received by pediatric patients who underwent a chest X-ray examination while being treated in the NICU and PICU rooms at Hermina Karawang Hospital. The research involved measuring the radiation dose in pediatric patients using the OSLD nanoDot. This susceptible device can detect low-dose X-ray radiation exposure, especially in pediatric patients. The study was conducted from September to December 2022 and included 35 patients aged 0 to 5. The results of the ESD measurements received by pediatric patients at Hermina Karawang Hospital in the 0-1 year age group were found to be in line with the DRL (Diagnostic Reference Levels) of the United Kingdom (UK) and Austria, which recommend a range of 0.05 – 0.055 mGy. The average ESD value for this age group was 0.05 mGy. Similarly, for the 1-5 year age group, an average ESD value of 0.048 mGy was obtained, below the UK and Austria DRL range of 0.05 – 0.069 mGy. These results indicate that the ESD received by pediatric patients during thoracic examination at Hermina Karawang Hospital is close to the DRL values recommended by the UK and Austria. However, it is essential to note that regardless of the dose received, it must always be justified and optimized to prevent unnecessary radiation exposure. Keywords: ESD, OSLD, unnecessary exposure, paediatric radiation protection, radiation exposure

Measurement of Entrance Surface Air Kerma of plain abdominal radiography in some Nigerian health facilities

Background : Patient dose assessments in many Nigerian radiological departments have shown large inter- and intra-hospital variations for the same type of radiological examinations, hence, there is a need for regular monitoring of radiological equipment and measurement of patient dose in our health facilities. The main objective of this survey was to evaluate the Entrance Surface Dose Air Kerma (ESAK) of the patients who underwent abdominal (anteroposterior; AP) radiography in ten health facilities in Southern Nigeria.&#x0D; Material and Methods: A total of ten health facilities comprising private and public health facilities were included in this investigation. A total of 223 adult patients who weighed within 70±5kg `were considered in this survey. The ESAK was calculated from the tube output of the x-ray machines and the exposure parameters utilized during examinations according to the International Atomic Energy Agency code of practice.&#x0D; Results : The mean ESAK values obtained from the health centres ranged from 1.00 milligray (mGy) to 17.21mGy. The maximum/minimum ratio of individual ESAK which is the range factor (RF) varied from 1.3 to 6.1.&#x0D; Conclusion and Recommendation : Variations were observed in patient dose values among radiological units. The entrance surface air kerma (ESAK) obtained in the study were comparable with the dose values in the UK- 2010 review in most cases. The intra-radiological unit patient dose variations, as revealed by the range factor show that the operation technique employed was not fully optimized and that dose reduction is possible without degrading image quality. Therefore, there is a need for regular monitoring of radiographic equipment and periodic surveys of the patient dose.

Evaluation of the Entrance Surface Doses (ESD) for common diagnostic X-ray examinations

ObjectiveThe purpose of this study was to assess the Entrance Skin Dose (ESD) in patients undergoing multiple types of radiographic examinations across three hospitals in Saudi Arabia. MethodsThe patient ESD was estimated directly using optically stimulated luminesces (OSL) and indirectly using a survey meter and calculations for 100 adult patients undergoing common diagnostic X-ray examinations, including a posterior anterior chest, posterior anterior hand, anterior posterior foot, and anterior posterior knee examinations, in three hospitals in Saudi Arabia. Comparative analysis with national and international reference values was conducted. ResultsOur analyses revealed considerable heterogeneity in X-ray exposure parameters among the hospitals. The mean ESD values for the chest examination were 0.28 ± 0.13 mGy for the direct method and 0.19 ± 0.11 mGy for the indirect method. Hand examination using the direct method resulted in a mean ESD of 0.42 ± 0.15 mGy, while the indirect method yielded 0.23 ± 0.06 mGy. Remarkably, the ESD values in most cases exceeded national and international guidelines, with the knee examination ESD using the direct and indirect methods showing an alarming value of 1.54 ± 0.31 mGy and 1.18 ± 0.21 mGy, respectively. The correlation between direct ESD, indirect ESD showed a strong positive correlation exists between direct ESD and Indirect ESD (r = 0.8, p < 0.001). ConclusionThe study highlights the urgent need for standardized protocols and quality control measures across radiographic facilities in Saudi Arabia. The elevated ESD values signify a critical issue that requires immediate attention to minimize patient radiation exposure while maintaining diagnostic image quality. Quality control tests and adjustments in examination parameters are strongly advised.

CNR performance of semiconductor materials for X-ray imaging of breast calcifications

We present the results of a GAMOS/GEANT4 computer simulation of a standard X-ray mammography system, which consists of a Tungsten 28 kVp polychromatic X-ray source with a 50 μm Rh filter, a mammography phantom with Al2O3 spherical specks of different diameters, and a generic pixel detector (55 μm × 55 μm pixel size) with different types of semiconductor sensors. The number of photons simulated is calibrated to produce similar entrance surface dose (ESD) as the one used by a standard clinical mammography screening. Estimates of Contrast to Noise Ratio (CNR) as a function of ESD, sensor thickness and microcalcification diameter are presented for four different sensor materials: Silicon (Si), Cadmium Telluride (CdTe), Gallium Arsenide (GaAs) and Perovskite (MAPbI3). For the X-ray energy spectrum and pixel size considered, and an ESD dose of 4 mGy, our study shows that, with the exception of Si, these sensors, as thin as 200 μm, are able to resolve (with at least 3 standard deviations above background) Al2O3 spherical specks up to a minimum diameter of 180 μm, having statistically compatible CNR performance. The increase in substrate thickness has a substantial improvement in the CNR values provided by the Si sensor, while for the other cases the enhancement of CNR is marginal and consistent with statistical uncertainties with the thinnest case considered.

EVALUASI DOSE-AREA PRODUCT DAN WAKTU FLUOROSKOPI SEBAGAI METRIK DOSIS PADA AUDIT DOSIS PROSEDUR FLUOROSKOPI INTERVENSIONAL: STUDI MULTISENTER

This study aims to evaluate conventional dose metrics, namely Dose-Area Product (DAP) and fluoroscopy time, commonly used in interventional fluoroscopy procedure dose audits, by comparing them to a dose metric that more closely represents the dose at the patient's skin, namely Entrance Surface Dose (ESD). The research was conducted by first calculating the ESD using AndroidTM-based software from a previous study (Mulia et al., 2020) with retrospective data from 2 (two) hospitals (20 patients each) that utilized the Philips Allura XPer FD20 interventional fluoroscopy system. The results showed that DAP and fluoroscopy time did not exhibit a linear correlation with the skin dose represented by ESD, with R2 values of 0.11 for Hospital A and 0.79 for Hospital B. Consequently, the DAP and fluoroscopy time dose metrics were deemed insufficient in representing the actual skin dose received by the patients. This study recommends medical physicists also include ESD calculations and utilize them in radiation dose audits as supplementary data to monitor patient deterministic effects directly. Keywords: skin dose, kerma, DAP, dose, interventional

Feasibility of new patient dose management tool in digital radiography: Using clinical exposure index data of mobile chest radiography in a large university hospital

The clinical anteroposterior (AP) chest images taken with a mobile radiography system were analyzed in this study to utilize the clinical exposure index (EI) as a patient dose-monitoring tool. The digital imaging and communications in medicine header of 6048 data points exposed under the 90 kVp and 2.5 mAs were extracted using Python for identifying the distribution of clinical EI. Even under the same exposure conditions, the clinical EI distribution was 137.82–4924.38. To determine the cause, the effect of a patient's body shape on EI was confirmed using actual clinical chest AP image data binarized into 0 and 255-pixel values using Python. As a result, the relationship between the direct X-ray area of the chest AP image, the higher the clinical EI, the larger the rate of the direct X-ray area. A conversion equation was also derived to infer entrance surface dose through clinical EI based on the patient thickness. This confirmed the possibility of directly monitoring patient dose through EI without a dosimeter in real-time. Therefore, to use the clinical EI of the mobile radiography system as a patient dose-monitoring tool, the derivation method of clinical EI considers several factors, such as the relationship between patient factors.

Estimation of Entrance Surface Dose and Dose Area Product in Most Frequently Used Radiography Examinations in Hamadan

Background: Radiation dose in C-arm procedure and radiography may lead to late complications such as cancer. Entrance surface dose (ESD) and dose area product (DAP) are two practical indicators for patient dose estimation. This study aimed to calculate ESD and DAP based on exposure parameters for the most common radiographic examinations in educational hospitals of Hamadan. Methods: This work was conducted in three radiography centers in Hamadan in 2020. ESD was determined using a standard equation. Radiation parameters, including maximum kilovolt and milliampere-seconds (mAs), were obtained from the device console, and the output factor was obtained from the calibration certificate. Eventually, ESD and DAP were computed for the head, chest, abdomen, and pelvic radiography examinations. Results: Means of ESD and DAP were 0.68±0.44 mGy and 274.03±179.84 mGy.cm2 for head, as well as 0.13±0.07 mGy and 117.64±70.07 mGy.cm2 for chest. In addition, the corresponding valures were 1.31±0.82 mGy and 1187.17±738.3 mGy.cm2 for the abdomen, as well as 0.84±0.83 mGy and 764.84±753.59 mGy.cm2 for the pelvic. The difference in ESD and DAP for all examinations between centers was significant (P&lt;0.05). Conclusion: Several factors affect radiation exposure and patient dose in radiography. Some of these factors are subjective and depend on technician knowledge. It is possible to reduce the patients’ dose while maintaining image quality by regular training of technicians.