Dose-area Product Meter Research Articles

The Efficiency of Applying the Radiology Technologist of the Radiation Dose Monitoring Technique During the Fluoroscopy Procedures for Oncology in Paediatrics Care Aged Between 4 to 7 Years

Fluoroscopy is one of the radiation sources used in diagnostic processes in radiology. Owing to the diagnostic approach that entails observation of the affected anatomy using radiation in real time, harmful effects may potentially occur. Therefore, safety measures in the radiographer's use of equipment and effective monitoring and management are essential in diagnostic processes. Additionally, patients in the age group of four to seven years have less anatomy and tissue development, which presents higher levels of health risks. The study will focus on analyzing the pre-procedure requirements and the set of guidelines, which enable the enforcement of the safety of the concerned patients within the paediatric practice. For example, the study will observe the potency of undertaking the reduction of the fluoroscopic times and improving the communications between the health specialists. The study will also evaluate methods and techniques employed in achieving efficiency in fluoroscopy radiation dose management. Direct and indirect methods will be employed to monitor the dosage effects. Direct methods would entail performing a skin dose test on the target area of fluoroscopic radiation. Detectors would be employed, for example the photographic films and thermo-luminescent dosimeters. The indirect methods will employ the use of the dose area product meter to ascertain the effects of radiation on the patients. Some of the dose reduction techniques involve the manipulation of equipment operation, for example beam quality adjustment, dose level setting, and dose spreading. The results used to evaluate the dosage level will entail analyzing measurements of the skin exposure unit of the fluoroscopic equipment. These results will be achieved through the use of different operational voltage levels on the fluoroscopic equipment. Skin dose will be determined through a combination of several measurable factors in fluoroscopic equipment operation.

Local diagnostic reference levels for intraoral dental radiography in the public hospitals of Cyprus

PurposeThe purpose of this study was to determine local DRLs for children and adults undergoing intraoral dental examinations at the intraoral radiology units of the public hospitals in Cyprus. MethodsMeasurements were made on all the twenty intraoral X-ray units of the public hospitals in Cyprus with the intention to establish the local DRLs for all the possible intraoral X-ray examinations for children and adults. All units are film based. The measurements were made by a Dose Area Product (DAP) meter (GAMMEX RMI 841-RD) placed at the surface of the dental unit’s X-ray shaping cone (FSD 20cm). A diagnostic radiology dosimeter (Dosimax Plus A) was also placed at an FSD of 100cm to compare the dose reading between the two dosimeters. ResultsDRLs were established at the 3rd quartile for 7 exposure settings corresponding to 12 types of teeth (Adult and children mandibular and maxillary incisor, premolar and molar) with values of 197, 163, 128, 102, 81, 65 and 49mGycm−2 and 7.23, 5.94, 4.75, 3.68, 3.10, 2.41 and 1.88mGy for benchmark nominal exposure times of 1000, 800, 640, 500, 400, 320 and 250ms respectively, at a nominal exposure voltage of 70kVp. ConclusionsThe local DRLs of the present study compare well with other similar published DRLs.

Patient and staff dosimetry during radiographic procedures in an intensive care unit

The performance of radiography in the Intensive Care Unit (ICU) may be associated with a certain level of radiation exposure for staff and patients in the unit. Little evidence on exposure levels is available in the literature. However, healthcare professionals in the ICUs at our centre tend to leave the room during radiographic examinations, potentially compromising patient care.The objectives of this study were to quantify dose levels within the ICU and to evaluate the performance of ICU x-ray studies according to patient dose measurements.This study was conducted in the 18-bed ICU of a third-level hospital. The scattering radiation due to mobile x-ray examinations was measured by using four personal thermoluminiscent dosimeters (TLDs). The dose area product (DAP) was measured at each examination using a transmission chamber installed on the diaphragm of the x-ray equipment.Based on the TLD readings and taking account of the error margin, the annual dose to patients and staff was less than 0.6 mSv. The value given by the DAP meter for chest x-rays was 94 ± 17 mGy cm2; this value is well below the lower limit recommended by different agencies and committees.Exposure levels were found to be extremely low and pose no apparent risk to staff or to those in beds adjacent to the patients undergoing x-ray examinations, which were correctly performed in the unit.

Ultra-low iodine concentrations iso-attenuating with diagnostic 0.5 M gadolinium in endovascular procedures to minimize the risk of contrast nephropathy: A phantom study

PurposeTo establish the concentrations of iodine contrast media (I-CM) iso-attenuating with 0.5M gadolinium contrast media (Gd-CM), regarded diagnostic in catheter angiography and vascular interventions in azotemic patients, at various X-ray tube potentials with correlation to skin radiation dose. Materials and method20-mL syringes filled with 30, 40, 50, 70 and 90mgI/mL, 0.5M Gd-CM and air were placed in a water-equivalent phantom and exposed at about 50, 60, 70, 80 and 90kV in an X-ray angiographic system. Relative contrast between the contrast materials and the background phantom material was measured on a PACS workstation. Radiation entrance dose, measured with a dose meter and estimated from the dose-area-product (DAP), was adjusted for radiation backscatter to simulate absorbed skin dose. ResultThe iodine concentrations 30, 40, 50, 70 and 90mg/mL resulted in the same relative contrast as 0.5M gadolinium at 53, 57, 62, 71 and 85kVp, respectively. Air had lower relative contrast than all iodine concentrations at all kVp-settings except for 30mgI/mL above 84kVp. The measured skin radiation dose was less than 1mGy per exposure at all kVp-settings, and around 25–30% lower than the dose estimations derived from the angiographic system's in-built DAP meter. ConclusionLow-kilovoltage X-ray technique and ultra-low concentrations of I-CM iso-attenuating with 0.5M Gd-CM may be utilizable in peripheral arteriography and endovascular interventions, to minimize the total CM-dose to avoid CIN in azotemic patients.

Transition from image intensifier to flat panel detector in interventional cardiology: Impact of radiation dose

Flat panel detector (FPD) technology in interventional cardiology is on the increase due to its varied advantages compared to the conventional image intensifier (II) systems. It is not clear whether FPD imparts lower radiation doses compared to II systems though a few studies support this finding. This study intends to compare radiation doses from II and FPD systems for coronaryangiography (CAG) and Percutaneous Transluminal Coronary Angioplasty (PTCA) performed in a tertiary referral center. Radiation doses were measured using dose area product (DAP) meter from patients who underwent CAG (n = 222) and PTCA (n = 75) performed using FPD angiography system. The DAP values from FPD were compared with earlier reported data using II systems from the same referral center where the study was conducted. The mean DAP values from FPD system for CAG and PTCA were 24.35 and 63.64 Gycm2 and those from II system were 27.71 and 65.44 Gycm2. Transition from II to FPD system requires stringent dose optimization strategies right from the initial period of installation.

Optimisation of direct digital chest radiography using Cu filtration

PurposeTo assess the impact of additional Cu filtration with the DRX-1 detector in optimisation of adult chest radiography. MethodsA simulated anatomical phantom was imaged at different levels of Cu filtration (0 mm, 0.1 mm, 0.3 mm and 0.5 mm of Cu) at 120 kVp. Image quality was assessed using exposure index, conspicuity index, signal-to-noise ratio and pixel density. Dose area product (DAP) meter was used to measure dose; effective dose and risk of exposure induced cancer death (REID) were estimated using the PCXMC software 2.0. ResultsExposure index increased with increasing Cu thickness; 0.3 mm Cu filtration increased conspicuity index of simulated nodules, with a minimal decrease in signal-to-noise ratio, and pronounced decrease in pixel density. Patient doses were reduced by 20.7%, 36.6%, and 39.79% at 0.1 mm, 0.3 mm, and 0.5 mm levels of Cu filtration respectively. ConclusionAdditional beam filtration using 0.3 mm Cu filter with the DXR-1 detector reduced patient doses by 37% without decline in image quality.

Panoral dose assessment: a comparative report of methodologies

National guidance from the Institute of Physics and Engineering in Medicine (IPEM Report 91) currently recommends that the patient dose for a panoral X-ray unit is measured as dose area product (DAP) replacing dose width product described in earlier guidance. An investigation identifying different methods available to carry out this measurement has been undertaken and errors in the methodologies analysed. It has been shown that there may be up to a 30 % variation in DAP measurement between methods. This paper recommends that where possible a DAP meter is used to measure the dose-area product from a panoral X-ray unit to give a direct DAP measurement. However, by using a solid-state dose measurement and film/ruler to calculate DAP the authors have established a conversion factor of 1.4. It is strongly recommended that wherever a DAP value is quoted the methodology used to obtain that value is also reported.

Conversion coefficients for the estimation of effective dose in cone-beam CT

PurposeTo determine the conversion coefficients (CCs) from the dose-area product (DAP) value to effective dose in cone-beam CT.Materials and MethodsA CBCT scanner with four fields of view (FOV) was used. Using two exposure settings of the adult standard and low dose exposure, DAP values were measured with a DAP meter in C mode (200mm×179 mm), P mode (154 mm×154 mm), I mode (102 mm×102 mm), and D mode (51 mm×51 mm). The effective doses were also investigated at each mode using an adult male head and neck phantom and thermoluminescent chips. Linear regressive analysis of the DAP and effective dose values was used to calculate the CCs for each CBCT examination.ResultsFor the C mode, the P mode at the maxilla, and the P mode at the mandible, the CCs were 0.049 µSv/mGycm2, 0.067 µSv/mGycm2, and 0.064 µSv/mGycm2, respectively. For the I mode, the CCs at the maxilla and mandible were 0.076 µSv/mGycm2 and 0.095 µSv/mGycm2, respectively. For the D mode at the maxillary incisors, molars, and mandibular molars, the CCs were 0.038 µSv/mGycm2, 0.041 µSv/mGycm2, and 0.146 µSv/mGycm2, respectively.ConclusionThe CCs in one CBCT device with fixed 80 kV ranged from 0.038 µSv/mGycm2 to 0.146 µSv/mGycm2 according to the imaging modes and irradiated region and were highest for the D mode at the mandibular molar.

Monte Carlo simulation-based feasibility study of a dose-area product meter built into a collimator for diagnostic X-ray

According to the International Electro-technical Commission, manufacturers of X-ray equipment should indicate the number of radiation doses to which a patient can be exposed. Dose-area product (DAP) meters are readily available devices that provide dose indices. Collimators are the most commonly employed radiation beam restrictors in X-ray equipment. DAP meters are attached to the lower surface of a collimator. A DAP meter consists of a chamber and electronics. This separation makes it difficult for operators to maintain the accuracy of a DAP meter. Developing a comprehensive system that has a DAP meter in place of a mirror in the collimator would be effective for measuring, recording the dose and maintaining the quality of the DAP meter. This study was conducted through experimental measurements and a simulation. A DAP meter built into a collimator was found to be feasible when its reading was multiplied by a correction factor.

Evaluation of Maximum Patient Skin Dose Arising from Interventional Cardiology Using Thermoluminescence Dosimeter in Mashhad, Iran

Introduction The increasing practice of interventional fluoroscopy in diagnosis and treatment of cardiovascular disease has risen attention to improve radiation protection of patients and cardiologists in these relatively high dose techniques. Therefore, nowadays there is an emphasis on the measurement of radiation dose received by patients and cardiologists arising from the relevant procedures. Materials and Methods Maximum skin dose of 90 patients in two hospitals in Mashhad have been measured by a grid of 30 thermoluminescent dosimeters (TLDs). The X-ray units were Axiom Artis Siemens in both hospitals which were equipped with integrated dose area product (DAP) meters. The procedures were divided into two groups: diagnostic procedures (angiography and angiography with measurement of left or right ventricle and pulmonary artery) and therapeutic procedures (angioplasty with or without dilatation or stent and angiography with angioplasty). DAP value, fluoro time, and cumulative dose at Interventional Reference Point (CDIRP) were also registered for each procedure. Results The mean values of maximum skin dose (MSD) and DAP for diagnostic procedures were 68.51 mGy and 20.96 Gy.cm2, respectively and for therapeutic procedures 344.18 mGy and 70.94 Gy.cm2, respectively. A good correlation was found between MSD and DAP (R=0.88) but correlation between MSD and CDIRP was stronger (R=0.90). Conclusion MSD values did not exceed the 2000 mGy dose threshold for deterministic effects. The highest MSD obtained for diagnostic procedures was 229.40 mGy and for therapeutic procedures it was 820.50 mGy. The results show that CDIRP can be a fairly good estimate of MSD.

디지털 심혈관조영장치의 기하학적 특성에 따른 선량 감소

심혈관 촬영 시 선량감소를 위해 실무자가 조절 가능한 기하학적 특성을 살펴보고, 각 특성에 따른 유효선량을 비교해 보았다. 인체 모형 팬텀을 이용하여 투시촬영과 영화촬영을 시행하였고, 선량의 측정은 심혈관 장치의 DAP meter를 이용하여 DAP 값을 유효선량으로 환산하였다. 먼저 영화촬영은 투시촬영에 비해 기하학적 특성 전반에 걸쳐서 선량이 약 6-7배 높았다. FPS mode에 따른 선량은 FPS를 낮게 설정할수록 선량이 70%까지 감소하였다. 선관 각도에 따른 선량은 LAO <TEX>$45^{\circ}$</TEX>+Caudal <TEX>$30^{\circ}$</TEX>이 가장 높게 측정되었고, 조사야 조절장치를 많이 적용할수록 선량은 감소하였다. X-선관과 영상증배관의 거리가 10 cm 멀어질수록 투시촬영과 영화촬영에서 각각 선량이 25-35%까지 증가하였다. FOV가 확대될수록 선량이 1.21-2배 증가하였고, 테이블과 영상증배관 거리가 10cm 멀어질수록 선량은 1.11-1.25배 까지 증가하였다. 따라서 본 연구에서 실험한 기하학적 특성인 FPS mode, 선관 각도, 조준기, 선관과 영상증배관 거리, 테이블과과 영상증배관 거리, FOV 영상 확대 등은 중재적 시술 시 실무자가 수시로 조절 가능한 인자이며, 각 특성에 따라 선량 감소 효과를 기대할 수 있다. This study aims to find out geometric parameters which practitioner adjustable to reduce dose in coronary angiography. We take fluoroscopy and cine exposure by use of phantom, and got dose use the dose-area product(DAP) meter of angiography device, than convert DAP to effective dose. As results, Cine exposure shows higher dose measurement about 6-7 times than fluoroscopy. Dose in frame per second(FPS) mode could be decrease down to 70%, as lower FPS. In view of X-ray tube angle, LAO <TEX>$45^{\circ}$</TEX>+Caudal <TEX>$30^{\circ}$</TEX> shows highest dose measurement. More use of Collimator, lower dose measurement. Source-image intensifier distance(SID) get longer to 10cm, dose of each fluoroscopy and cine exposure increase up to 25-30%. Image magnification of field of view(FOV) could increase dose up to 1.21-2 times. Also table-image intensifier distance get longer to 10cm, dose increased 1.11-1.25 times. Practitioner can adjust several geometric parameters, as FPS mode, tube angle, Collimation, SID, table-image intensifier distance, FOV. And each factors can reduce radiation dose in coronary angiography.

Radiation dose optimization research: Exposure technique approaches in CR imaging – A literature review

The purpose of this paper is to review the literature on exposure technique approaches in Computed Radiography (CR) imaging as a means of radiation dose optimization in CR imaging. Specifically the review assessed three approaches: optimization of kVp; optimization of mAs; and optimization of the Exposure Indicator (EI) in practice. Only papers dating back to 2005 were described in this review.The major themes, patterns, and common findings from the literature reviewed showed that important features are related to radiation dose management strategies for digital radiography include identification of the EI as a dose control mechanism and as a “surrogate for dose management”. In addition the use of the EI has been viewed as an opportunity for dose optimization. Furthermore optimization research has focussed mainly on optimizing the kVp in CR imaging as a means of implementing the ALARA philosophy, and studies have concentrated on mainly chest imaging using different CR systems such as those commercially available from Fuji, Agfa, Kodak, and Konica-Minolta. These studies have produced “conflicting results”. In addition, a common pattern was the use of automatic exposure control (AEC) and the measurement of constant effective dose, and the use of a dose-area product (DAP) meter.

SU‐E‐I‐31: Moving From Image Intensifier to Flat Panel Detector in Interventional Radiology: Initial Experiences in a Tertiary Referral Center in India

Purpose: To audit radiation doses imparted to patients from interventional procedures performed in image intensifier and flat panel based interventional systems in a tertiary referral center in India. Methods: Forty cerebral angiographies were performed using Siemens Multistar top Image intensifier (II) and nine using Artis Zee flat panel detector (FPD) based angiographic systems. Dose area product (DAP) meter was used to measure dose imparted to patients during interventional procedures. Dose audit involved assessment of radiation dose, exposure parameters and image quality relevant to the examination. Copper filtration of 0.2mm was selected in the II based system, whereas 0.6mm copper filters were selected in FPD system. Subjective evaluation of image quality was performed by the interventionalists performing the procedure. Results: The mean DAP values for cerebral angiography using II and FPD systems were 127.5 (32.96 to 366.47) and 94.6 (26.31 to 228.68) Gy cm2 respectively. Dose reduction of about 26 % without sacrificing diagnostic information was achieved using FPD compared to the II system. Conclusion: It is necessary to orient the interventional staff to strictly adhere to low dose protocols so that inadvertent selection of preset protocols may impart high doses to patients. Further data collection on several other interventions is necessary in order set reference levels for Indian adult. At present using low dose protocols involving high filtration does not degrade image quality and are suggestive for use in FPD systems for the Indian adult.

The establishment of local diagnostic reference levels for paediatric interventional cardiology

BackgroundThere is a paucity of information worldwide on radiation exposure in paediatric interventional cardiology. At present Nationally established Diagnostic Reference Levels exist for adult interventional cardiology procedures in the UK but little data is available for paediatrics. In addition, interventional cardiology has been identified as one the highest contributors to medical exposure to ionising radiation and children are more radiosensitive than adults. ObjectiveThis study sought to determine current radiation dose levels in paediatric interventional cardiology (IC) with a view to establishing local diagnostic reference levels (LDRL). MethodsRadiation dose and examination details were recorded for 354 paediatric patients examined by IC in a specialised paediatric centre in Europe. Radiation doses were recorded using a Dose Area Product meter along with examination details. Procedures were categorised as either diagnostic (A) or therapeutic (B). Data was further sub-divided into five age ranges; (1) newborn <1 year (2) 1 <5 years (3) 5 <10 years (4) 10 <15 years (5) 15 years and over. Proposed LDRL were calculated from the mean dose area product readings. ResultsThe mean patient age was 2.6 years (range 0.0 days–16 years) and weight was 14.9 kg (range 2.4–112 kg). LDRL for the five age groupings were calculated as 190, 421, 582, 1289 and 1776 cGycm² respectively. ConclusionLocal dose reference levels have been proposed for paediatric IC and can be used as a benchmark for other hospitals to compare against their own radiation doses.

Dose indices in dental cone beam CT and correlation with dose–area product

In the 2011 project "Safety and efficacy of a new and emerging dental X-ray modality (SEDENTEXCT)", it was suggested that dose index (DI) and dose-area product (DAP) could be easily measured and used as diagnostic reference levels (DRLs), which would help in the management of radiation doses to patients in optimum exposure settings. Such indices could be directly related to effective dose. The purposes of this study, therefore, were to measure and calculate the DI and DAP in cone beam CT (CBCT) machines and to evaluate the correlation between the two. Dose measurements were performed on three-dimensional cone beam CT (3D-CBCT) machines [3D Accuitomo (J. Morita Mfg. Corp., Kyoto, Japan), Veraviewepocs (J. Morita Mfg. Corp.) and CS9300 (Carestream, New York, NY)] by exposing a cylindrical poly-methyl methacrylate (PMMA) phantom using a CT ionization chamber. These dose measurements were used for the calculation of Dose Indices 1 and 2, according to the methodology suggested by SEDENTEXCT. The DAP was measured using a DAP meter that was attached to the detector to cover the entire irradiated area. The DI1 ranged from 53.6 mR to 216.6 mR, the DI2 ranged from 77.1 mR to 325.0 mR and the DAP ranged from 101.1 mGy cm(2) to 457.9 mGy cm(2), depending on the machines and exposure settings. Index 2 had a better correlation with the DAP than Index 1. The DIs and DAP proposed by SEDENTEXCT may be useful for establishing DRLs for dental CBCT machines; however, further studies are necessary to determine which of these indices provide accurate dose estimates proportionally relating to the effective dose.

PF8 Expandable intramedullary nailing: a new method in the treatment of femoral periprosthetic fractures

Introduction: High doses of ionizing radiation are used during surgeries such as interlocking intra-medullary nailing and minimally invasive plate osteosynthesis. So, excessive use of fluoroscopy is seen to be a feared procedure among orthopedic surgeons. DAP (Dose area product) values which shows the total radiation dose with the aid of preinstalled DAPmeters, can bemonitored on the recent fluoroscopic units in mGy·cm2 or mGy·m2. This value is a more reliable indicator than the fluoroscopy time. The aim of the study is to investigate the total fluoroscopic DAP values in interlocking intramedullary nailing operations and comparing the total values with other radiologic procedures. Materials and Methods: Between 2010 and 2012, nine patients underwent femoral locking intramedullary nailing operation in our institute. Total DAP values, fluoroscopy time and number of images were retrieved from the fluoroscopic unit’s HDD. We have also recorded the DAP values of postoperative direct roentgenograms which were taken with portable digital x-ray machine which has on-board DAP meter. While the mean operation time was 3.2 hours (2–4.2 hours), total fluoroscopy use was 1.6 minutes (0.8–3.1 minutes). Results: Total mean DAP value was resulted in 1720mGy·cm2 and total number of fluoroscopic images were 44 (16–82). The mean DAP for postoperative AP and lateral direct femur radiographs were 1790mGy·cm2 and 2100mGy·cm2 respectively. We have found the total fluoroscopic unit DAP values comparable with even AP or lateral direct radiograms. Conclusion: DAP value is more practical than the fluoroscopy time in monitoring the total radiation dose used in the orthopedic procedures. If properly adjusted preoperatively, fluoroscopic units are more reliable and safe than the direct radiographies. We recommend routineuse of fluoroscopy insteadof direct radiographies intraoperatively.

A method to derive appropriate exposure parameters from target exposure index and patient thickness in pediatric digital radiography

Little information exists concerning appropriate exposure and measuring overall patient dose in pediatric digital radiography. To establish a convenient method of appropriate exposure from target exposure index (EI) and thickness in pediatric digital radiography and estimate patient entrance-surface dose (ESD) and dose-area product (DAP) associated with chest, abdomen and pelvis radiography. A formula was deduced to calculate appropriate mAs changed with children's weight and height. EI was used to control image quality. With this formula, dose-optimized procedures were carried out. Data were collected from 180 pediatric examinations, including chest, abdomen and pelvis anterior-posterior (AP) projections. The children were divided into the following age bands: newborns (0-28days), infants (28days-2years) and older children (2-7years). In each age band, ten children were exposed with the calculated appropriate mAs and EI values were kept steady in appropriate range (referred as target group) and ten children were exposed to the factors routinely used in practice (referred to as the routine group). DAP to children was measured with a DAP meter, and ESD was calculated using measured DAP and data from the National Radiological Protection Board. Data were compared between groups. ESD ranges in the target group were 32-202μGy (chest AP), 57-333μGy (abdomen AP) and 52-372μGy (pelvis AP). For every radiographic procedure, chi-square Student's t tests showed a significant difference in average ESD and DAP between the two groups (P < 0.005). Most ESD values from the routine group were two times higher than those from the target group. The study established a convenient method to set appropriate exposure parameters (mAs) to reach a target EI using the child's weight and height in pediatric radiography. By this method, ESD and DAP can be significantly reduced in children.

Evaluation of the radiation dose to a phantom for various X-ray exposure factors performed using the dose area product in digital radiography

The aim of this study is to measure the dose area product (DAP) in digital radiography by using a DAP meter to determine the X-ray exposure. Pediatric X-ray examinations can be obtained for any radiographic examinations using the selected radiographic examination parameters (kVp and mAs), the DAP information recorded. The best peak signal-to-noise ratio (PSNR) at a fixed tube voltage of 70 kVp was obtained at tube currents of 20 and 32 mA, whereas the best PSNR at a fixed tube current of 25 mA was obtained at a tube voltage of 73 kVp. The fixed tube voltage of 70 kVp and the fixed tube current of 25 mA could help to obtain the best image quality and depict the spatial resolution of an anthropomorphic torso phantom radiographic examination. The normalized data over the DAP were provided to determine the patient dose from radiography.

Development of a scintillating fiber-optic dosimeter for measuring the entrance surface dose in diagnostic radiology

Abstract As a direct method, a scintillating fiber-optic dosimeter (SFOD) was fabricated using an organic scintillator, a plastic optical fiber, and a photomultiplier tube (PMT) to measure entrance surface doses (ESDs) in diagnostic radiology. In this study, we measured the scintillating lights, which are altered by to the exposure parameters, such as the tube potential, current-time product, and focus-surface distance (FSD), with an SFOD placed on the top of an acrylic and aluminum chest phantom to provide a backscatter medium. The scintillating light signals of the SFOD were compared with the ESDs obtained using conventional dosimeters. The ESDs that were measured using the dose-area product (DAP) meter, as an indirect method, and a semiconductor dosimeter, as a direct method, were distinguished according to differences in the measurement position and the method used. In the case of the two direct methods with the SFOD and the semiconductor dosimeter, the output light signals of the SFOD were similar to the ESDs of the semiconductor dosimeter. It is expected that the SFOD will be a useful dosimeter for diagnostic radiology due to its many advantages, including its small size, lightweight, substantial flexibility, remote sensing, real-time monitoring, and immunity to electromagnetic interference (EMI).

Estimation of radiation dose and risk to children undergoing cardiac catheterization for the treatment of a congenital heart disease using Monte Carlo simulations

Children diagnosed with congenital heart disease often undergo cardiac catheterization for their treatment, which involves the use of ionizing radiation and therefore a risk of radiation-induced cancer. The purpose of this study was to calculate the effective and equivalent organ doses (H(T)) in those children and estimate the risk of exposure-induced death. Fifty-three children were divided into three groups: atrial septal defect (ASD), ventricular septal defect (VSD) and patent ductus arteriosus (PDA). In all procedures, the exposure conditions and the dose-area product meters readings were recorded for each individual acquisition. Monte Carlo simulations were run using the PCXMC 2.0 code and mathematical phantoms simulating a child's anatomy. The H(T) values to all irradiated organs and the resulting E and risk of exposure-induced death values were calculated. The average dose-area product values were, respectively, 40 ± 12Gy·cm(2) for the ASD, 17.5 ± 0.7Gy·cm(2) for the VSD and 9.5 ± 1Gy·cm(2) for the PDA group. The average E values were 40 ± 12, 22 ± 2.5 and 17 ± 3.6mSv for ASD, VSD and PDA groups, respectively. The respective estimated risk of exposure-induced death values per procedure were 0.109, 0.106 and 0.067%. Cardiac catheterizations in children involve a considerable risk for radiation-induced cancer that has to be further reduced.