Entrance Dose Rate Research Articles

Technical note: A comparison of physician doses in C-Arm and CT fluoroscopy procedures.

We address the misconception that the typical physician dose is higher for CT fluoroscopy (CTF) procedures compared to C-Arm procedures. We compare physician scatter doses using two methods: a literature review of reported doses and a model based on a modified form of the dose area product (DAP). We define thismodified form of DAP, "cumulative absorbed DAP," as the product of the area of the x-ray beam striking the patient, the dose rate per unit area, and the exposure time. The patient entrance dose rate for C-Arm fluoroscopy (0.2mGy/s) was found to be 15 times lower than for CT fluoroscopy (3mGy/s). A typical beam entrance area for C-Arm fluoroscopy reported in the literature was found to be 10.6×10.6cm (112cm2), whereas for CTF was 0.75×32cm (24cm2). The absorbed DAP rate for C-Arm fluoroscopy (22mGy*cm2/s) was found to be 3.3 times lower than for CTF (72mGy*cm2/s). The mean fluoroscopy time for C-Arm procedures (710s) was found to be 21 times higher than for CT fluoroscopy procedures (23s). The cumulative absorbed DAP for C-Arm procedures was found to be 9.4 times higher when compared to CT procedures (1.59 mGy*m2 vs. 0.17 mGy*m2). The higher fluoroscopy time in C-Arm procedures leads to a much lower cumulative DAP (i.e., physician scatter dose) in CTF procedures. This result can inform interventional physicians deciding on whether to perform inter-procedural imaging inside the room as opposed to retreating from the room.

Influence of radiation dose reduction gloves on exposure parameters, entrance dose rates and eye doses of interventionalists during mobile C-arm fluoroscopic procedures: A phantom study

IntroductionDuring fluoroscopic examinations, radiation dose reduction gloves (RRGs) protect the hands of the interventionalist against ionising scattered radiation from the patient. Some fluoroscopic procedures may require the hands of the interventionalist in the path of the primary X-ray beam. This study investigates the influence of RRGs in the field of view (FOV) on exposure parameters, entrance dose rates and eye doses of interventionalists during mobile C-arm fluoroscopic procedures. MethodPolymethylmethacrylate (PMMA) slabs were stacked on each other to simulate patient thicknesses. The abdomen protocol of the unit was selected for the study. The entrance dose rates to the surface of the PMMA slabs and the scattered radiation were measured for an undercouch configuration with and without RRGs in the FOV. The exposure parameters were noted. The scattered radiation for an overcouch configuration was measured. ResultsThe entrance dose rate increases as the FOV decreases for a fixed thickness of PMMA. The presence of RRGs in the FOV increases the exposure parameters, entrance dose rates and the scattered radiation to the eyes of the interventionalist. For the first level of RRG coverage, percentage increases in entrance dose rates and eye doses for the 23 cm FOV for all thicknesses of PMMA slabs ranged from 1.0% to 17.0% and 20.0%–30.0%, respectively; for the second level of RRG coverage, the entrance dose rates ranged from 17.0% to 45.0% and the eye doses from 50.0% to 60.0%. Percentage increases depend on the FOV, the patient's thickness, and the size and orientation of the RRGs in the FOV. Scattered radiation to the eyes of the interventionalist increases with an overcouch configuration compared to an undercouch configuration. ConclusionSterile RRGs protects the hands of the interventionalist against scattered radiation. But in the FOV, they increase the scattered radiation to the personnel and the patient entrance dose rate. Implications for practiceFor best practice in C-arm fluoroscopy-guided procedures, appropriate FOV and C-arm orientation should be selected, whilst RRGs should not be in the path of the primary beam unless necessary.

Development of a dose-rate dosimeter for x-ray CT scanner using silicon x-ray diode.

In an x-ray diagnosis, it is important to evaluate the entrance dose rate, as the dose rate of exposure becomes highest in that position. To investigate the effect of the entrance dose rate of x-ray CT scanners, a dose-rate dosimeter comprising a silicon x-ray diode (Si-XD), a CMOS dual operational amplifier, resistors, capacitors, and a mini-substrate measuring 20 × 17mm2 were developed. The Si-XD is desirable for measuring the changing entrance dose rate, as it enables the reduction of the response time, dimensions, and cost of the dosimeter. The dosimeter was connected to a microcomputer (mbed), and the output voltages from the dosimeter were measured using an analog-digital converter in the mbed. The output voltages were proportional to the tube currents at a constant tube voltage of 100 kV using an industrial x-ray tube, and the calibrated dose rates corresponded well to those obtained using a commercially available semiconductor dosimeter. However, owing to the energy dependence of the dosimeter, the calibrated dose rate was ∼10% higher than that of a commercially available semiconductor dosimeter at the lower tube voltage. In the angular dependence of the dosimeter, the flatness measured from 60° to 120° was ∼103% in this study. A fundamental study for measuring the dose-rate variations with rotation was performed. The results showed a different profile than the angular dependence due to the distance from the source and the complex factors of the scattered radiation.

Establishment of Microbeam Radiation Therapy at a Small-Animal Irradiator

Microbeam radiation therapy is a preclinical concept in radiation oncology. It spares normal tissue more effectively than conventional radiation therapy at equal tumor control. The radiation field consists of peak regions with doses of several hundred gray, whereas doses between the peaks (valleys) are below the tissue tolerance level. Widths and distances of the beams are in the submillimeter range for microbeam radiation therapy. A similar alternative concept with beam widths and distances in the millimeter range is presented by minibeam radiation therapy. Although both methods were developed at large synchrotron facilities, compact alternative sources have been proposed recently. A small-animal irradiator was fitted with a special 3-layered collimator that is used for preclinical research and produces microbeams of flexible width of up to 100 μm. Film dosimetry provided measurements of the dose distributions and was compared with Monte Carlo dose predictions. Moreover, the micronucleus assay in Chinese hamster CHO-K1 cells was used as a biological dosimeter. The focal spot size and beam emission angle of the x-ray tube were modified to optimize peak dose rate, peak-to-valley dose ratio (PVDR), beam shape, and field homogeneity. An equivalent collimator with slit widths of up to 500 μm produced minibeams and allowed for comparison of microbeam and minibeam field characteristics. The setup achieved peak entrance dose rates of 8 Gy/min and PVDRs >30 for microbeams. Agreement between Monte Carlo simulations and film dosimetry is generally better for larger beam widths; qualitative measurements validated Monte Carlo predicted results. A smaller focal spot enhances PVDRs and reduces beam penumbras but substantially reduces the dose rate. A reduction of the beam emission angle improves the PVDR, beam penumbras, and dose rate without impairing field homogeneity. Minibeams showed similar field characteristics compared with microbeams at the same ratio of beam width and distance but had better agreement with simulations. The developed setup is already in use for invitro experiments and soon for invivo irradiations. Deviations between Monte Carlo simulations and film dosimetry are attributed to scattering at the collimator surface and manufacturing inaccuracies and are a matter of ongoing research.

Intraoperative 2D C-arm and 3D O-arm in children: a comparative phantom study.

:PurposeExposure to ionizing radiation is a concern for children during intraoperative imaging. We aimed to assess the radiation exposure to the paediatric patient with 2D and 3D imaging.MethodsTo evaluate the radiation exposure, patient absorbed doses to the organs were measured in an anthropomorphic phantom representing a five-year-old child, using thermoluminescent dosimeters. For comparative purposes, organ doses were measured using a C-arm for one minute of fluoroscopy and one acquisition with an O-arm. The cone-beam was centred on the pelvis. Direct and scattered irradiations were measured and compared (Student’s t-test). Skin entrance dose rates were also evaluated.ResultsAll radiation doses were expressed in µGy. Direct radiation doses of pelvic organs were between 631.22 and 1691.87 for the O-arm and between 214.08 and 737.51 for the C-arm, and were not significant (p = 0.07). Close scattered radiation on abdominal organs were between 25.11 and 114.85 for the O-arm and between 8.03 and 55.34 for the C-arm, and were not significant (p = 0.07). Far scattered radiation doses on thorax, neck and head varied from 0.86 to 6.42 for the O-arm and from 0.04 to 3.08 for the C-arm, and were significant (p = 0.02). The dose rate at the skin entrance was 328.58 µGy.s−1 for the O-arm and 1.90 with the C-arm.ConclusionDuring imaging of the pelvis, absorbed doses for a 3D O-arm acquisition were higher than with one minute fluoroscopy with the C-arm. Further clinical studies comparing effective doses are needed to assess ionizing risks of the intraoperative imaging systems in children.

Reducing the risk of skin injuries in cardiac catheterization procedures: Optimization proposal for obese patients

PurposeDuring interventional cardiology procedures, high doses of X-ray may be delivered to patients. This is especially critical in cases of obese patients and/or high obliquity projections. High dose rates can then be produced in patients’ skin as well as insufficient image quality due to regulatory limitations in the X-ray tube output working in the fluoroscopy mode. In this paper, an optimization action is proposed to reduce patient entrance dose rate and preserve image quality in cases of thick patients. MethodsThe action is based on the evaluation of dose rate to the patient and image quality in a new fluoroscopy protocol with less frame rate (7.5 vs. 15 frames/s) and higher spectral shape filter (0.4 vs. 0.1 mm Cu). The new protocol is tested in an angiography room using a PMMA phantom and a test object. ResultsThe new fluoroscopy protocol (7.5 fr/s and 0.4 mm Cu) reduces entrance surface air kerma in 70%–10% (depending on PMMA thickness), preserving the incident air kerma per frame at the image detector. While at lower PMMA thickness, the MTF measured with bar pattern is better for the default protocol; at PMMA thickness between 32 and 37 cm, the optimized protocol produces better image quality indicators. ConclusionsThis work demonstrates that in the case of high thicknesses of PMMA (32–37 cm), increasing spectral beam filter and reducing frame rate may help improve image quality and maintain entrance surface air kerma so as to fulfil the regulatory requirements.

OA195] Dosimetric evaluation of the O-arm® imaging system

Purpose Three-dimensional (3D) imaging devices are emerging in operating theatres for intra-operative applications. Although there are reported benefits of this technology, such as increased surgical accuracy and higher patient safety, radiation exposure of staff and patient remains a concern. This study aims at evaluating this exposure when using the O-arm® (2D and 3D imaging device). Methods To assess patient radiation exposure, absorbed doses to organs were measured on two anthropomorphic phantoms representing a five-year-old child and an adult female. The phantoms are made of slabs containing holes at the location of different organs, where thermoluminescent detectors (TLDs) were placed. Organ doses were measured for one 3D-acquisition of the O-arm® and during one minute of fluoroscopy using a conventional C-arm for comparative purposes. Skin entrance dose rates were also evaluated during 2D fluoroscopy by measuring incident kerma rates on the phantom. Staff exposure was evaluated by creating a 2D ambient equivalent dose cartography of the operating theatre for a single 3D O-arm® acquisition. Moreover, whole body and eye lens doses to the O-arm® technician were measured by placing an anthropomorphic phantom equipped with TLDs. Results Phantom organ doses for one 3D pelvic acquisition with the O-arm® ranged from 4.0 μGy to 6.7 mGy for the adult and from 0.9 μGy to 1.7 mGy for the child; on average 4 times higher than doses obtained after one minute of fluoroscopy with the C-Arm. Consistently, kerma rates at the surface of the skin were between 6 and 164 times lower for the C-Arm compared to the O-arm®. Results from the cartography showed that at 2 m from the isocenter, the maximum ambient equivalent dose is 11 μSv per acquisition and 3 μSv at the technician’s position. Dosimeters placed on the technician phantom showed doses below the detection limit (i.e. 0.1 mSv). Conclusions Doses delivered to the patient during a 3D acquisition of the O-Arm® are systematically higher than the corresponding irradiation with the C-arm. The staff, if positioned as far as possible from the isocenter and adequately equipped with protective gear, may remain inside the operative room during an O-arm® 3D acquisition.

Estimation of dose rates at the entrance surface for exposure scenarios of total body irradiation using MCNPX code

One of the main criteria that must be held in Total Body Irradiation (TBI) is the uniformity of dose in the body. In TBI procedures the certification that the prescribed doses are absorbed in organs is made with dosimeters positioned on the patient skin. In this work, we modelled TBI scenarios in the MCNPX code to estimate the entrance dose rate in the skin for comparison and validation of simulations with experimental measurements from literature. Dose rates were estimated simulating an ionization chamber laterally positioned on thorax, abdomen, leg and thigh. Four exposure scenarios were simulated: ionization chamber (S1), TBI room (S2), and patient represented by hybrid phantom (S3) and water stylized phantom (S4) in sitting posture. The posture of the patient in experimental work was better represented by S4 compared with hybrid phantom, and this led to minimum and maximum percentage differences of 1.31% and 6.25% to experimental measurements for thorax and thigh regions, respectively. As for all simulations reported here the percentage differences in the estimated dose rates were less than 10%, we considered that the obtained results are consistent with experimental measurements and the modelled scenarios are suitable to estimate the absorbed dose in organs during TBI procedure.

Correlation between scatter radiation dose at height of operator's eye and dose to patient for different angiographic projections

Studies have reported cases of radiation-induced cataract among cardiology professionals. In view of the evidence of epidemiological studies, the ICRP recommends a new threshold for opacities and a new radiation dose to eye lens limit of 20mSv per year for occupational exposure. The aim of this paper is to report scattered radiation doses at the height of the operator's eye in an interventional cardiology facility without considering radiation protection devices and to correlate these values with different angiographic projections and operational modes. Measurements were taken in a cardiac laboratory with an angiography X-ray system equipped with flat-panel detector. PMMA plates of 30×30×5cm were used with a thickness of 20cm. Measurements were taken in two fluoroscopy modes (low and normal, 15pulses/s) and in cine mode (15frames/s). Four angiographic projections were used: anterior posterior; lateral; left anterior oblique caudal (spider); and left anterior oblique cranial, with a cardiac protocol for patients weighing between 70 and 90kg. Measurements of phantom entrance dose rate and scatter dose rate were performed with two Unfors Xi plus detectors. The detector measuring scatter radiation was positioned at the usual distance of the cardiologist's eyes during working conditions. There is a good linear correlation between the kerma area product and scatter dose at the lens. Experimental correlation factors of 2.3, 12.0, 12.2 and 17.6μSv/Gycm2 were found for different projections. PMMA entrance dose rates for low and medium fluoroscopy and cine modes were 13, 39 and 282mGy/min, respectively, for AP projection.

Fetal Radiation Dose in Prophylactic Uterine Arterial Embolization

The purpose of the study was to estimate the absorbed dose (AD) to the fetus for pregnant patients with placenta accreta undergoing fluoroscopy imaging during prophylactic catheterization and uterine artery embolization. We hypothesize that after optimizing the use of the radiation, this endovascular method is safe. Catheterization was performed for seven women before their elective cesarean section. The correct position of the catheter was confirmed by a radiologist using a small bolus of contrast medium and optimized pulsed fluoroscopy imaging. For the AD measurements of the fetus, four radiophotoluminescence dosimeters were placed in the vaginal fornix. Dose area product (DAP), entrance skin exposure (ESE), fluoroscopy time (Tf), and dose rate also was recorded. The mean values of the radiation exposure for the seven patients were as follows: AD in the vaginal fornix was 11.2 (range 2.2-28.7)mGy, DAP 1,122 (648-2,001)cGycm(2), ESE 120 (63-184)mGy, Tf 7:31 (5:05-11:35)min:sec, and dose rate 15 (8-21)mGy/min, respectively. This study revealed that the AD to the fetus due to the endovascular method can be reduced to be below the risk for developmental disorders when pulsed fluoroscopy with an optimized protocol is used without angiography exposures.

Measuring patient entrance dose rates on fluoroscopy systems for larger size patients

Measuring patient entrance dose rates on fluoroscopy systems for larger size patients

SU-D-144-04: Physiologically Gated Microbeam Radiation Therapy Using Electronically Controlled Field Emission X-Ray Source Array

Purpose: Microbeam radiation therapy (MRT) is an experimental pre‐clinical technique using arrays of microscopically‐thin, low‐energy X‐ray radiation to treat radio‐resistant, deep‐seated tumors. All previous MRT experiments were performed using synchrotron radiation. We have developed a compact MRT small animal system using carbon nanotube (CNT) field emission x‐ray technology. Our purpose is to incorporate respiratory gating to the MRT system, minimizing motion blurring and increasing the peak‐to‐valley‐dose ratio (PVDR), which is important for normal tissue sparing. Methods: A prototype CNT MRT system was employed. The intrinsically divergent radiation is collimated into ∼300um microbeams using an external collimator. Parallel microbeam planes were delivered by translating the object perpendicular to the microbeam plane in a step‐and‐shoot fashion. The device generated an average entrance dose rate of 1Gy/minute. For respiratory‐gated irradiation, electron field emission from CNT cathodes was synchronized with the respiratory cycle of the mouse so x‐ray radiation is only extracted during the motionless phase of respiration.A phantom simulating mouse respiration used a servo motor pushing on a pressure sensor in a typical breathing pattern. A control program used the signal to trigger x‐ray irradiation during the motionless phase. Two experiments were run: a single line irradiation at 160 kVp delivering 0.9 Gy/min for 5 minutes, and three such lines of irradiation separated by 900um. Dose profiles were measured with EBT2 Gafchromic dosimetry films. Results: A single beam showed a FWTM increase from 638 to 1088um with un‐gated motion. With gating, the FWTM was 669um, similar to the motionless case.PVDR quantifies MRT effectiveness in the case of multiple lines. Motion reduces PVDR 50 percent; with gating PVDR is almost entirely recovered, 5.5 percent higher than without motion. Conclusion: Gated MRT largely eliminates microbeam broadening from physiological motion, maintaining high PVDR. The technique increases precision and will be tested during MRT treatments.

Development and Dosimetry of a Small Animal Lung Irradiation Platform

Advances in large scale screening of medical countermeasures for radiation-induced normal tissue toxicity are currently hampered by animal irradiation paradigms that are both inefficient and highly variable among institutions. Here, a novel high-throughput small animal irradiation platform is introduced for use in orthovoltage small animal irradiators. Radiochromic film and metal oxide semiconductor field effect transistor detectors were used to examine several parameters, including 2D field uniformity, dose rate consistency, and shielding transmission. The authors posit that this setup will improve efficiency of drug screens by allowing for simultaneous targeted irradiation of multiple animals to improve efficiency within a single institution. Additionally, they suggest that measurement of the described parameters in all centers conducting countermeasure studies will improve the translatability of findings among institutions. The use of tissue equivalent phantoms in performing dosimetry measurements for small animal irradiation experiments was also investigated. Though these phantoms are commonly used in dosimetry, the authors recorded a significant difference in both the entrance and target tissue dose rates between euthanized rats and mice with implanted detectors and the corresponding phantom measurement. This suggests that measurements using these phantoms may not provide accurate dosimetry for in vivo experiments. Based on these measurements, the authors propose that this small animal irradiation platform can increase the capacity of animal studies by allowing for more efficient animal irradiation. They also suggest that researchers fully characterize the parameters of whatever radiation setup is in use in order to facilitate better comparison among institutions.

Improving safety in the electrophysiology laboratory using a simple radiation dose reduction strategy: a study of 1007 radiofrequency ablation procedures

BackgroundThe use of fluoroscopic screening involves exposure to ionising radiation for both patients and operators.ObjectiveTo assess the effects of radiation dose reduction manoeuvres (DRM) during radiofrequency ablation (RFA) procedures.DesignProspective study...

Overlap of radiation field and radiation field shape in cardiac catheterization

The radiation field shape for cardiac catheterization has changed from being circular to being rectangular with the spread of flat-panel detector systems. A rectangular radiation field provides a wide fluoroscopy field to the four corners of a subject area; however, in cardiac catheterization, there is not much usable information around the four corners at several angles, and this tends to be regarded as a meaningless radiation exposure. Hence, overlap of radiation fields has been of concern recently. The authors changed field sizes/fluoroscopy angles and examined entrance dose rates to study radiation field shapes and configurations of radiation exposure to patients, and they discussed a radiation exposure reduction method. In measurements of phantom entrance dose rates, we considered right anterior oblique (RAO) directions, cranial (CRA) directions and RAO-CRA directions and found that entrance dose rates rose considerably, particularly at the RAO-CRA. In the study of radiation field overlap, we discuss radiation field shapes (rectangular/circular) as well as angles. In the RAO-CRA directions, differences occurred in angles of non-overlapping radiation field by differences in radiation field shapes. For RAO-CRA, compared with the RAO and CRA directions, entrance dose rates increased with an increase in angle. When convenience in clinics is considered, the utilization frequency of the four corners of a rectangular field is low. When one considers the increases in radiation exposure caused by radiation field overlap, it is more effective to use circular radiation fields.

Staff Radiation Doses in Interventional Cardiology: Correlation With Patient Exposure

In pediatric interventional cardiology, cardiologists need to stay closer to the patient than during adult catheterization, and the use of biplane systems increases the scatter radiation. Occupational radiation risk is rather high, and estimation of lens doses becomes necessary. Deriving factors for assessing these doses from the patient doses displayed in catheterization laboratories can help in preserving staff radiation safety. A biplane X-ray system and polymethylmethacrylate plates of 4 to 20 cm to simulate pediatric patients have been used. Patient entrance dose rates, dose-area product, and doses to the eyes of the cardiologists for the typical operation modes have been measured. Correlations between patient and staff doses have been obtained. Scatter dose rates increase by a factor of 92 from low fluoroscopy to cine acquisition when phantom thickness increases from 4 to 20 cm. Scatter doses increase linearly with dose-area product for all the thicknesses. Administration of 1 Gy x cm(2) to the patient involves 7 microSv to the eyes of the cardiologist (without extra protection). In conclusion, the experimental correlation factors found between phantom and scatter doses allow a fairly good estimation of staff doses from the dosimetric patient data.

Does digital flat detector technology tip the scale towards better image quality or reduced patient dose in interventional cardiology?

As dynamic flat-panel detectors (FD) are introduced in interventional cardiology (IC), the relation between patient dose and image quality (IQ) needs to be reconsidered for this type of image receptor. On one hand this study investigates IQ of a FD system by means of a threshold contrast-detail analysis and compares it to an image intensifier (II) system on a similar X-ray setup. On the other hand patient dose for coronary angiography (CA) procedures on both systems is compared by Dose-Area Product (DAP)-registration of a patient population. The comparative IQ study was performed for a range of entrance dose rates (EDR) covering the fluoroscopy and cinegraphy working mode. In addition the IQ investigation was extended to a similar study under automatic brightness control (ABC). As well the systematic study of IQ as a function of EDR as the study performed under ABC point to a better IQ for FD in cinegraphy mode and no difference between both systems in fluoroscopy mode. The patient population study resulted in mean DAP values of 31 Gy cm 2 (II system) and 33 Gy cm 2 (FD system) ( p = 0.68) for CA procedures. As well total DAP as contributions of fluoroscopy and cinegraphy on both systems are not significantly different. To conclude, we could state that profit was taken from the intrinsic better performance of the FD for cinegraphy mode in producing higher quality images in this mode but without any effect on patient dose for CA procedures.

Comparison of radiation dose to patient and staff for two interventional cardiology units: a phantom study

The purpose of this investigation was to measure the patient and staff dose during routine interventional cardiology procedures for an image intensifier-based and a flat detector system using a water phantom. The Integris BH3000 image intensifier-based (Philips) and the Axiom Artis flat detector-based (Siemens) angiography units were used in this study. The accuracy of tubes potential and irradiation timers and also internal dosimeters were verified and confirmed. A water phantom with a thickness of 18 cm was used for patient and staff dose measurements. For the Philips system, phantom entrance dose rates were 2.77 and 38.97 microGym(2) s(-1) during fluoroscopy and cineangiography. The respective dose rates for the Siemens were 1.98 and 13.46 microGym(2) s(-1). Phantom entrance dose rate was 28.5 and 65% higher for the Philips system during fluoroscopy and cineangiography, respectively. Comparing the scattered dose rates at the operator location showed that the flat detector-based Siemens system delivers five times lower dose to the operator in comparison with the image intensifier-based Philips unit. The results suggest that the decrease in received dose of the patient and staff is achievable using the flat detector system. In addition, application of lead curtain and glass is recommended to lower the cardiologist dose especially for the image intensifier-based Philips system.

Patient dose in interventional radiology: a European survey

Patient doses for a few common fluoroscopy-guided procedures in interventional radiology (IR) (excluding cardiology) were collected from a few radiological departments in 13 European countries. The major aim was to evaluate patient doses for the basis of the reference levels. In total, data for 20 procedures for about 1300 patients were collected. There were many-fold variations in the number of IR equipment and procedures per population, in the entrance dose rates, and in the patient dose data (total dose area product or DAP, fluoroscopy time and number of frames). There was no clear correlation between the total DAP and entrance dose rate, or between the total DAP and fluoroscopy time, indicating that a number of parameters affect the differences. Because of the limited number of patients, preliminary reference levels were proposed only for a few procedures. There is a need to improve the optimisation of IR procedures and their definitions and grouping, in order to account for their different complexities.

Survey on performance assessment of cardiac angiography systems

Advances in imaging technology have facilitated the development of increasingly complex interventional cardiac equipment. Consequently, there is a need for definitive equipment requirements. The aim of the study is to assess the performances of different cardiac angiographic systems. A questionnaire was sent to centres participating in SENTINEL Project to collect dosimetry data (typical entrance dose rate in fluoroscopy and imaging mode), image quality evaluations (low and high contrast resolutions) and KAP calibration factors. Results from this survey could contribute to the explanation of patient dose variability in angiographic cardiac procedures and to derive reference levels for cardiac angiographic equipment performance parameters.