Radiation doses to patients undergoing coronary angiography and percutaneous transluminal coronary angioplasty

A detailed study of radiation doses received by 168 patients who underwent coronary angiography (CAG) and 102 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) in two Greek hospitals is presented. Radiation dose was measured in terms of dose-area product (DAP). The contribution of fluoroscopy and cineradiography to the total DAP was examined separately for each radiological projection used in both procedures. Effective dose and doses to various organs were estimated with the help of the ODS-60 software. Total DAP was found to correlate linearly to fluoroscopy time and cine film length. Mean DAP values were found to be 80.8 +/- 28.0 Gy cm2 for CAG and 86.2 +/- 65.6 Gy cm2 for PTCAs, whereas the estimated mean values of effective dose were 20.9 +/- 7.5 and 23.2 +/- 18.1 mSv respectively. DAP to effective dose conversion coefficients were estimated to be 0.26 mSv/Gy cm2 for CAG and 0.27 mSv/Gy cm2 for PTCAs.     

Comparison of patient doses in interventional radiology procedures performed in two large hospitals in Greece

Purpose of the study was to determine patient doses in the most common interventional radiology (IR) procedures performed in two large Greek hospitals. A total of 164 patients who underwent 4 types of IR procedures were studied. Fluoroscopy time, total exposure time, number of frames, number of runs, radiation field size, and cumulative dose-area product (DAP) were recorded. The median DAP values for carotid arteriography and lower limb arteriography were 66 and 123 Gy cm2 for hospital 'A' and 21 and 49 Gy cm2 for hospital 'B'. For the cerebral arteriographies performed in hospital 'A', the median DAP was 116 Gy cm2, while for the hepatic embolizations performed in hospital 'B', it was 104 Gy cm2. The DAP values observed in hospital 'A' for carotid arteriography and lower limb arteriography were almost three times than those of hospital 'B'. From the data analysis, it is evident that dose optimization in hospital 'A' should be pursued through revision of the techniques used.     

Optimisation strategies and justification: an example in uterine artery embolisation for fibroids

Radiation risk has to be justified and optimised. This study discusses the radiation risk of uterine artery embolisation (UAE) for the treatment of fibroids. A total of 70 consecutive UAE dosimetry parameters were assessed. Using Monte Carlo simulation, organ and effective doses and dose conversion coefficients (DCCs) (mSv Gy cm(-2)) were calculated. During UAE optimisation, avoidance of oblique views and use of last-image-hold (LIH) documentation instead of digital subtraction angiography (DSA) were investigated. Mean dose-area product (DAP) was 37.1 Gy cm2 (median 23.7 Gy cm2) and mean fluoroscopy time was 18.4 min (median 16.6 min). Dose values decreased as the study progressed: mean DAP for patients 1-21, 68.5 Gy cm2; patients 22-43, 35.7 Gy cm2; and patients 44-69, 13.0 Gy cm2. Average DCC for DSA image procedures was 0.572, yielding a mean effective dose of 29.6 mSv (median 17.1 mSv). For LIH-only procedures, an average DCC of 0.813 was estimated [using mean effective dose: 10.6 mSv (median 8.1 mSv)].     

Increases in patient doses need to be avoided when upgrading interventional cardiology systems to flat detectors

The aim of this study was to evaluate patient doses in two interventional cardiology laboratories over a period of 1 y in which the imaging devices were changed from image intensifier (II) to flat detector (FD). Dosimetric data from a total of 1040 coronary angiography (CA) procedures and 1087 percutaneous transluminal coronary angioplasty (PTCA) procedures were gathered. During the period studied with II imaging, median values of dose area product were 28 Gy cm(2) for CA and 57 Gy cm(2) for PTCA. In the first half of the year with FD imaging, median values were 37 Gy cm(2) for CA and 89 Gy cm(2) for PTCA. A significant increase in patient doses was noticed in the early stages of use of FD technology for imaging IC procedures, while fluoroscopy time and number of images remained similar. A careful setting of the X-ray systems, after upgrading the imaging system, is essential to avoid unjustified increases in patient doses.     

Correlation of patient maximum skin doses in cardiac procedures with various dose indicators

In most countries of European Union, legislation requires the determination of the total skin dose received by patients during interventional procedures in order to prevent deterministic damages. Various dose indicators like dose-area product (DAP), cumulative dose (CD) and entrance dose at the patient plane (EFD) are used for patient dosimetry purposes in clinical practice. This study aimed at relating those dose indicators with doses ascribed to the most irradiated areas of the patient skin usually expressed in terms of local maximal skin dose (MSD). The study was performed in two different facilities for two most common cardiac procedures coronary angiography (CA) and percutaneous coronary interventions (PCI). For CA procedures, the registered values of fluoroscopy time, total DAP and MSD were in the range (0.7-27.3) min, (16-317) Gy cm(2) and (43-1507) mGy, respectively, and for interventions, accordingly (2.1-43.6) min, (17-425) Gy cm(2), (71-1555) mGy. Moreover, for CA procedures, CD and EFD were in the ranges (295-4689) mGy and (121-1768) mGy and for PCI (267-6524) mGy and (68-2279) mGy, respectively. No general and satisfactory correlation was found for safe estimation of MSD. However, results show that the best dose indicator which might serve for rough, preliminary estimation is DAP value. In the study, the appropriate trigger levels were proposed for both facilities.     

Radiation doses to patients from enteroclysis

The purpose of this study was to determine the patient doses during enteroclysis and compare them with the available bibliographical data. For 14 enteroclysis examinations, the dose-area product (DAP) meter readings, fluoroscopy time, number of radiographs and exposure data were recorded. From these data, the fluoroscopy and radiography contributions to DAP, the entrance surface dose (ESD) and the effective dose (E) for each examination were estimated. The mean DAP was 81 Gy cm(2) and the mean fluoroscopy time was 19.5 min. The fluoroscopy contribution to DAP was 77% and 8.7 films were acquired in each examination on average. The mean ESD and E were estimated to be 428 mGy and 21 mSv, respectively. The mean DAP and fluoroscopy time calculated in this study are quite high when compared with those reported in the literature, suggesting that the examination technique should be reviewed and the ways to reduce patient exposure without compromising the diagnostic quality should be acquired.     

Effective dose to a patient undergoing coronary angiography

Detailed data relating to patient dose have been acquired for 18, randomly chosen, patients undergoing coronary angiographies. During the procedure, dose-area product (DAP), kV and beam collimation were recorded for each projection. Total DAP, fluoroscopy time and number of cine frames were also noted. Patient effective doses were calculated using two different methods. Mean and median DAP values were 58 and 56 Gy.cm2 respectively, with a range between 26 and 125 Gy.cm2, screening time ranged from 3 to 37 min and cine frames from 1013 to 2344, depending on patient size, examination protocol and complexity of procedure. Our results correspond well with those obtained by other authors. Differences in the estimation of effective doses, due to the calculation method used and the approximation made, are discussed.     

Dose conversion coefficients calculated using tomographic phantom, KTMAN-2, for X-ray examination of cardiac catheterisation

In this study, organ-absorbed doses and effective doses to patient during interventional radiological procedures were estimated using tomographic phantom, Korean Typical Man-2 (KTMAN-2). Four projections of cardiac catheterisation were simulated for dose calculation by Monte Carlo technique. The parameters of X-ray source and exposure conditions were obtained from literature data. Particle transport was simulated using general purposed Monte Carlo code, MCNPX 2.5.0. Organ-absorbed doses and effective doses were normalised to dose area product (DAP). The effective doses per DAP were between 0.1 and 0.5 mSv Gy(-1) per cm2. The results were compared with those derived from adult stylised phantom. KTMAN-2 received up to 105% higher effective doses than stylised phantom. The dose differences were mainly caused by more realistic internal topology of KTMAN-2 compared to stylised phantom that are closely positioned organs near the heart and shift of abdominal organs to the thoracic region due to supine position. The results of this study showed that tomographic phantoms are more suitable for dose assessment of supine patients undergoing the interventional radiology. The results derived from KTMAN-2 were the first radiation dose data based on non-Caucasian individuals for interventional procedures.     

Radiation doses to patients from digital subtraction angiography

This investigation determined patient doses during digital subtraction angiography (DSA). Fluoroscopy time, dose-area product (DAP) and entrance surface air kerma (ESAK) were analysed from 263 DSA examinations, classified into seven categories: (1) abdominal aorta, iliac, femoral, popliteal and leg arteries; (2) abdominal aorta and superselective DSA of renal arteries; (3) combination of (1) and (2); (4) superselective DSA of common carotid and vertebral arteries, intracranial branches in face and profile projections; (5) superselective DSA of hepatic, splenic, superior and inferior mesenteric arteries; (6) combination of (1) and (4); and (7) celiac trunk and branches. Median DAP values were 67.7, 92.9, 76.6, 53.6, 105.7, 76.1 and 2.6 Gy cm2, respectively. With the exception of one examination, ESAK values were below 2 Gy: the limit for erythema. Compared with published data, DAP values were within the range reported for (1) and (4), slightly larger for (2) and (5), whereas no references were identified for the remaining three categories.     

Skin dose measurements on patients for diagnostic and interventional neuroradiology: a multicentre study

The present study reports on the skin dose measurements on patients undergoing diagnostic and interventional neuroradiology procedures. Grids of thermoluminescence dosemeters were attached on the head of the patient. The exposure parameters of the X-ray systems and the clinical procedures were fully documented. While for the diagnostic procedure, the dose threshold of 2 Gy for deterministic effects was not reached, this situation was much different for the embolisations. For angiography of the carotid arteries, no skin doses were measured >320 mGy. For the cerebral embolisations, maximum skin doses up to 5.4 Gy were measured. Doses to the patients varied largely between different hospitals and within the same hospital for similar procedures. On the one hand, the complexity of the pathology for interventional procedures was responsible for the large variability in dose. On the other hand, large differences in clinical protocol and technical parameters of the X-ray systems, explaining the dose variations, were also observed. A correlation was found between the maximum skin dose measured on a patient and the total dose-area product (DAP) value for cerebral embolisations. This correlation makes it possible to estimate the maximum skin dose from these DAP values and to determine a trigger level. In conclusion, management of patient doses in interventional radiology requires training, specialisation and well-documented procedure guidelines.     

Organ and effective doses of patients arising from coronary angiography and percutaneous transluminal coronary angioplasty at two hospitals in Mashhad-Iran

A detailed study of radiation doses received by 83 patients who underwent coronary angiography (CA) and 26 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) by the femoral route in two hospitals in Mashhad-Iran is presented. All procedures were undertaken with Siemens angioscope X-ray equipment. Thermoluminescent dosimeters (TLD-100), suitably calibrated, were used to measure the dose received at five locations on the patient's skin (on the thyroid, gonads and lens of eyes). A dose area product (DAP) meter was also used. DAP values and fluoroscopy times were recorded for each patient. The mean values for DAP were 32.47+/-4.03 and 44.49+/-5.64 Gy cm2 for CA and PTCA, respectively. The patient dosimetry results revealed the thyroid receives the highest dose in CA and PTCA examinations. Also, in this study, DAP to effective dose conversion factors were estimated by means of a Rando phantom and the effective dose received by the patients was estimated for CA and PTCA examinations. The estimated mean values of effective dose were 6.75+/-0.85 and 9.61+/-1.24 mSv, respectively.     

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.     

Patient dose measurements in diagnostic radiology procedures in Montenegro

It was the aim of the study presented here to estimate for the first time patient dose levels in conventional diagnostic radiology in Montenegro. Measurements of patient dose in terms of entrance surface air kerma (ESAK) and kerma-area product (KAP) were performed on at least 10 patients for each examination type, in each of five randomly selected health institutions in Montenegro, so that a total of 872 patients for 16 different examination categories were included in the survey (817 patients for 1049 radiographies and 55 fluoroscopy patients). Exposure settings and individual data were recorded for each patient. Mean, median and third quartile values ESAK of patient doses are reported. The estimated mean ESAK values obtained are as follows: 4.7 mGy for pelvis anteroposterior (AP), 4.5 mGy for lumbar spine AP, 7.8 mGy for lumbar spine lateral (LAT), 3.1 mGy for thoracic spine AP and 4.3 mGy for thoracic spine LAT. When compared with the European diagnostic reference values, the mean ESAK for all studied examination types are found to be below the reference levels, except in chest radiography. Mean ESAK values for chest radiography are 0.9 mGy for posteroanterior (PA) projection and 2.0 mGy for LAT. The results exhibit a wide range of variation. For fluoroscopy examinations, the total KAP was measured. The mean KAP value per procedure for barium meal is found to be 22 Gy cm(2), 41 Gy cm(2) for barium enema and 19 Gy cm(2) for intravenous urography. Broad dose ranges for the same types of examinations indicate the necessity of applying practice optimisation in diagnostic radiology and establishment of national diagnostic reference levels.     

Patient skin dosimetry in haemodynamic and electrophysiology interventional cardiology

With the increase in number and complexity of interventional cardiology (IC) procedures, it is important to monitor skin dose in order to decrease skin injuries. This study investigated radiation doses for patients undergoing IC procedures, compare results with the literature and define a local dose-area product trigger level for operators to identify situations likely to exceed the threshold for transient skin erythema of 2 Gy. Dosimetric data were collected for 77 haemodynamic and 90 electrophysiological procedures. Mean maximum local skin doses (MSDs) were 0.28 Gy for coronary angiography, 1.03 Gy for percutaneous transluminal coronary angioplasty (PTCA), 0.03 Gy for pacemaker insertion, 0.17 Gy for radiofrequency ablation for nodal tachycardia, 0.10 Gy for WPW and 0.22 Gy for atrial flutter. Since MSD values for the other procedures were well below the deterministic effect limit, a trigger level of 140 Gy cm2 was derived for PTCA procedures alone.     

Patient dose during radiological examination in the follow-up of bariatric surgery

A patient dose survey was carried out measuring the kerma-area product (KAP) values during radiological evaluation in the follow-up of bariatric surgery. The procedures were performed by three radiologists to adjust laparoscopic gastric bands and to detect postoperative complications after Roux-en-Y gastric bypass procedures to treat morbid obesity. Total fluoroscopy time, exposure factors and the overall contribution of fluoroscopy to the accumulated KAP value were recorded. The median KAP values were used to estimate organ doses and effective dose to a standard patient; the radiation risk associated with the procedures was also evaluated. The doses were smaller for one of the three radiologists, owing to a more appropriate beam collimation and a reduction of the screening time. The KAP values ranged from 1.6 to 7.1 Gy cm(2) for the laparoscopic adjustable gastric banding management, and from 3.0 and 8.3 Gy cm(2) for the radiological examinations after gastric bypass. As a whole, the effective doses associated to these procedures were between 0.5 and 2.7 mSv. The organs receiving the highest doses were not only breast, stomach, pancreas and liver, but also lungs, owing to of their high radiosensitivity, significantly contributed to the effective dose.     

Exposure to patient during interventional endourological procedures

The purpose of this work is to study doses to patients undergoing interventional endourological procedures. The study was performed in a modern Clinic of Endourology and Shockwave Lithotripsy, equipped with two dedicated X-ray systems. The following information was recorded for each patient: type of the procedure, patient age, fluoroscopy time, number of images acquired and patient dose in air kerma-area product, P(KA), measured with KAP-meters integrated in the X-ray units. Eleven types of procedures were included. From the collected sample of 429 patients for all procedures, the mean fluoroscopy time varied between 0.2 and 4 min. The highest values of mean P(KA) 457 and 590 cGy cm(2) were found for percutaneous nephrolithotripsy and ureteroscopy, respectively. The mean values of P(KA) for rest of the procedures investigated were between 58 and 398 cGy cm(2). Individual patient doses varied between 2 and 2440 cGy cm(2) and fluoroscopy time--between 0.1 and 13.7 min. The first study in interventional endourology in Bulgaria demonstrated big variations in patient doses depending on the type and the complexity of procedure, operator's experience and exposure modes.     

Reference levels in PTCA as a function of procedure complexity

The multicentre assessment of a procedure complexity index (CI) for the introduction of reference levels (RLs) in percutaneous transluminal coronary angioplasties (PTCA) is presented here. PTCAs were investigated based on methodology proposed by Bernardi et al. Multiple linear stepwise regression analysis, including clinical, anatomical and technical factors, was performed to obtain fluoroscopy time predictors. Based on these regression coefficients, a scoring system was defined and CI obtained. CI was used to classify dose values into three groups: low, medium and high complexity procedures, since there was good correlation (r = 0.41; P < 0.001) between dose-area product (DAP) and CI. CI groups were determined by an ANOVA test, and the resulting DAP and fluoroscopy time third quartiles suggested as preliminary RLs in PTCA, as a function of procedure complexity. PTCA preliminary RLs for DAP are 54, 76 and 127 Gy cm2, and 12, 20 and 27 min for fluoroscopy time, for the three CI groups.     

Patient dosimetry in interventional cardiology at the University Hospital of Osijek

The interventional cardiology was recently implemented at the University Hospital of Osijek. Patients' absorbed doses during coronary angiography (CA) and the percutaneous transluminal coronary angioplasty (PTCA) procedures were measured and compared with published data and international standards. All patients undergoing CA or PTCA procedures during a 1-month period were included in the study. Patients' doses are expressed in terms of dose area product (DAP) per procedure. The patients' DAPs ranged from 2.6 to 210 Gy cm2 (average of 59 Gy cm2) during CAs, and from 61 to 220 Gy cm2 (average of 120 Gy cm2) during PTCAs. Patients' doses during CAs and PTCAs at the University Hospital of Osijek are in good agreement with the published ones. In complex cases, the radiochromic dosimetry films were used to show possible dose distributions across patient's skin. The film dosimetry showed a limitation of using only DAP values for the estimation of skin injuries risk.     

Variation in radiation doses in paediatric cardiac catheterisation procedures

Paediatric cardiac catheterisation involves diagnostic and therapeutic procedures that range from simple to complex and can subject paediatric patients to varying radiation doses. The study aims to determine the variation in entrance doses in patients in terms of dose-area product (DAP) values and to investigate the methods for optimising radiation protection. A total of 190 paediatric patients belonging to age groups 0, 1, 5 and 10 y who underwent diagnostic and six selected therapeutic procedures at King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia were included in the study. Therapeutic procedures include coarctation (COA), patent ductus arteriosus (PDA), radiofrequency ablation, pulmonary, embolisation and septostomy. Fluoroscopy and cine radiography were used in all procedures. Patient demography (weight, age, gender and height), radiographic technique factors, fluoroscopy and cine time, frame rate, and DAP values were taken from patients records. Effective doses for each procedure were estimated from the DAP values. The mean DAP per procedure were analysed for correlation with patient equivalent cylindrical diameter, weight, fluoroscopy time and number of frames. Factors influencing the variation in doses were investigated. Initial results show that PDA occlusion has the highest mean DAP value of 23.21 Gy-cm(2), while the diagnostic and septostomy procedures have the lowest value of 7.77 and 6.95 Gy-cm(2), respectively.     

Skin doses to patients undergoing coronary angiography in a Greek hospital

In this study, the skin dose (SD) to patients undergoing coronary angiography (CA) were measured with thermoluminescence dosemeters (TLD) attached to various anatomical locations on the patient's skin during 93 CA procedures in a Greek hospital. The dose-area product (DAP) for every radiological projection was also measured for each procedure. The SD values were measured to be in the range 2.4-427.5 mGy, lower than the 2 Gy dose threshold for transient erythema. No general correlation was observed between the SD and the total DAP.