Evaluation of patient-absorbed doses during coronary angiography and intervention by femoral and radial artery access

The aim of this study was to compare the radiation dose to patients during coronary angiography (CA) and coronary intervention (percutaneous transluminal coronary angioplasty, PTCA) by the femoral or radial artery access routes. A plane-parallel ionisation chamber, mounted on an under-couch X-ray tube (Siemens Coroskop TOP with an optional dose reduction system), recorded the dose-area product (DAP) to the patient from 40 coronary angiographies and 42 coronary interventions by the femoral route. The corresponding numbers for radial access were 36 and 24, respectively. Using a human-shaped phantom, conversion factors between maximum entrance surface dose and DAP were derived for CA and CA plus PTCA, respectively. The dose to the staff was measured with TL dosimeters for 22 examinations. Fluoroscopy time and DAP were significantly (p=0.003) larger using the radial access route for coronary angiography (7.5 min, 51 Gy cm²) than the corresponding values obtained from femoral access route (4.6 min, 38 Gy cm²). For CA plus PTCA the fluoroscopy time and DAP were larger for radial access (18.4 min, 75 Gy cm²) than for femoral access (12.5 min, 47 Gy cm²; p=0.013). In our experience, radial access did significantly prolong the fluoroscopy time and increase the patient doses.     

用胶片法对心脏介入程序中患者峰值皮肤剂量测量研究

目的 采用胶片法对进行心血管介入手术中患者所受峰值皮肤剂量（PSD）进行测量研究,包括冠状动脉血管造影术（CA）和经皮穿刺腔内冠状动脉成形术（PTCA）。方法 选用Gafchromic XR-RV3胶片在两家医院进行患者峰值皮肤剂量的测量。手术时将胶片放在患者身下的诊视床上。记录手术中监视器上显示的kV、mA、透视时间、剂量面积乘积（DAP）、参考点累积剂量等相关信息。采用Epson V750平板扫描仪对胶片进行分析扫描及分析,选用FilmQA软件分别测量图像的红、绿、蓝三色通道的像素值,使用红通道数据计算患者的 PSD。对PSD与设备显示参数进行相关分析,对相关的变量进行多元线性回归分析。结果 共测量CA手术26例,CA+PTCA手术19例。CA手术中,透视时间最高为17.62 min,累积剂量和DAP最大分别为1 498.50 mGy和109.68 Gy ·cm²,PSD最大为361.20 mGy。CA+PTCA手术中,曝光时间最长为64.48 min,累积剂量和DAP最大分别为6 976.20 mGy和5 336.00 Gy ·cm²,17例患者的PSD在1 Gy以内,1例患者PSD在1~2 Gy之间,1例患者PSD超出了发生皮肤损伤2 Gy的阈值,达到了2 195.70 mGy。CA程序中,患者PSD与DAP相关（R²=0.815,P<0.05）,CA+PTCA程序中,患者PSD与累积剂量相关（R²=0.916,P<0.05）。结论 心脏介入放射学程序中部分患者的PSD会超出ICRP建议的发生皮肤确定性效应的2 Gy阈值。DSA设备上显示的剂量相关的参数,只能粗略估算患者PSD的大小。使用XR-RV3胶片精确测量介入手术中患者的峰值皮肤剂量是一种非常快捷、有效的方法。     

Evaluation of exposure dose to patients undergoing catheter ablation procedures—a phantom study

The aim of this study was to evaluate entrance skin dose (ESD), organ dose and effective dose to patients undergoing catheter ablation for cardiac arrhythmias, based on the dosimetry in an anthropomorphic phantom. ESD values associated with mean fluoroscopy time and digital cine frames were in a range of 0.12–0.30 Gy in right anterior oblique (RAO) and 0.05–0.40 Gy in left anterior oblique (LAO) projection, the values which were less than a threshold dose of 2 Gy for the onset of skin injury. Organs that received high doses in ablation procedures were lung, followed by bone surface, esophagus, liver and red bone marrow. Doses for lung were 24.8–122.7 mGy, and effective doses were 7.9–34.8 mSv for mean fluoroscopy time of 23.4–92.3 min and digital cine frames of 263–511. Conversion coefficients of dose-area product (DAP) to ESD were 8.7 mGy/(Gy·cm²) in RAO and 7.4 mGy/(Gy·cm²) in LAO projection. The coefficients of DAP to the effective dose were 0.37 mSv/(Gy·cm²) in RAO, and 0.41 mSv/(Gy·cm²) in LAO projection. These coefficients enabled us to estimate patient exposure in real time by using monitored values of DAP.     

心血管病介入操作时患者受照剂量研究

目的 对心血管介入手术中患者所受辐射剂量及与辐射剂量相关的指标进行采集和分析,为改善患者的辐射防护提供依据.方法 对在省属三级甲等医院进行的26例完整的心血管介入手术的患者进行临床数据采集,按手术类别分成冠状动脉血管造影术(CA)及行冠状动脉血管造影术(CA)后继续行经皮穿刺腔内冠状动脉成形术(PTCA)两组,采用TLD个人剂量计照射野矩阵测量法,检测患者荧光照射时间、入射皮肤剂量(ESD)、最高皮肤剂量(PSD)、剂量-面积乘积(DAP)等指标,用TLD测量在模拟心血管手术条件下体模器官剂量.结果 荧光透视时间为(17.7±15.6)min,范围为0.80～42.4 min;ESD范围为(159±138)mGy,4.40～459 mGy;PSD范围为(769±705)mGy,22.6～2.43×103mGy.CA+PTCA组的荧光照射时间、ESD、PSD均大于CA组,差异有统计学意义.最大皮肤受照剂量与透视时间有较好的相关性(r=0.84,P＜0.01).结论 心血管病放射性介入操作时,可通过透视时间来估算最大皮肤受照剂量.

Abstract：

Objective To collect and analyze the radiation dose to patients in cardiovascular interventional procedures and the radiation dose-related indicators,in order to provide a basis for improving radiation protection of patients.MethodsThe clinical data of 26 cases of complete cardiovascular interventional procedures was collected in the municipal Grade A Class Three hospitals,including coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA),and the patient-received radiation doses and other related factors was studied.TLD personal dosimeter radiation field matrix method was used to measure fluorescence time,the entrance skin dose (ESD),the peak skin dose (PSD),dosearea product (DAP) and other indicators.TLD was used to measure the organ dose of the phantom under the cardiovascular interventional procedure condition.ResultsThe fluoroscopy time was (17.7 ±15.6) min during the range of 0.80-42.4 min.The average entrance skin dose (ESD) was (159 ± 138)mGy during the range of 4.40-459 mGy.The peak skin dose (PSD) was (769 ± 705) mGy during the range of 22.6 - 2.43 × 103mGy.The fluorescence time,entrance skin dose (ESD) ,peak skin dose (PSD) of the group CA + PTCA are greater than the group CA and the difference has statistical significan.The peak skin dose and the fluoroscopy time have good linear correlation (r = 0.84,P ＜ 0.01 ).Conclusion The peak skin dose the patient received in cardiovascular interventional radiological operation can be estimated through the fluoroscopy time.     

How to set up and apply reference levels in fluoroscopy at a national level

A nationwide survey was launched to investigate the use of fluoroscopy and establish national reference levels (RL) for dose-intensive procedures. The 2-year investigation covered five radiology and nine cardiology departments in public hospitals and private clinics, and focused on 12 examination types: 6 diagnostic and 6 interventional. A total of 1,000 examinations was registered. Information including the fluoroscopy time (T), the number of frames (N) and the dose-area product (DAP) was provided. The data set was used to establish the distributions of T, N and the DAP and the associated RL values. The examinations were pooled to improve the statistics. A wide variation in dose and image quality in fixed geometry was observed. As an example, the skin dose rate for abdominal examinations varied in the range of 10 to 45 mGy/min for comparable image quality. A wide variability was found for several types of examinations, mainly complex ones. DAP RLs of 210, 125, 80, 240, 440 and 110 Gy cm² were established for lower limb and iliac angiography, cerebral angiography, coronary angiography, biliary drainage and stenting, cerebral embolization and PTCA, respectively. The RL values established are compared to the data published in the literature.     

Contemporary Interventional Radiology Dosimetry: Analysis of 4,784 Discrete Procedures at a Single Institution

PurposeTo report dosimetry of commonly performed interventional radiology procedures and compare dose analogues to known reference levels.Materials and MethodsDemographic and dosimetry data were collected for gastrostomy, nephrostomy, peripherally inserted central catheter placement, visceral arteriography, hepatic chemoembolization, tunneled catheter placement, inferior vena cava filter placement, vascular embolization, transjugular liver biopsy, adrenal vein sampling, transjugular intrahepatic portosystemic shunt (TIPS) creation, and biliary drainage between June 12, 2014, and April 26, 2018, using integrated dosimetry software. In all, 4,784 procedures were analyzed. The study included 2,691 (56.2%) male subjects and 2,093 (43.8%) female subjects with mean age 55 ± 21 years (range: 0-104 years) and with mean weight of 76.9 ± 29.4 kg (range: 0.9-268.1 kg). Fluoroscopy time, dose area product (DAP), and reference dose were evaluated.ResultsTIPS had the highest mean fluoroscopy time (49.1 ± 16.0 min) followed by vascular embolization (25.2 ± 11.4 min), hepatic chemoembolization (18.8 ± 12.5 min), and visceral arteriography (17.7 ± 3.2 min). TIPS had the highest mean DAP (429.2 ± 244.8 grays per square centimeter [Gy·· cm²]) followed by hepatic chemoembolization (354.6 ± 78.6 Gy·· cm²), visceral arteriography (309.5 ± 39.0 Gy·· cm²), and vascular embolization (298.5 ± 29 Gy·· cm²). TIPS was associated with the highest mean reference dose (2.002 ± 1.420 Gy) followed by hepatic chemoembolization (1.746 ± 0.435 Gy), vascular embolization (1.615 ± 0.381 Gy), and visceral arteriography (1.558 ± 1.720 Gy). Of the six procedures available for comparison with the reference levels, the mean fluoroscopy time, DAP, and reference dose for each procedure were below the proposed reference levels.ConclusionAdvances in image acquisition technology and radiation safety protocols have significantly reduced the radiation exposure for a variety of interventional radiology procedures.     

Kodak EDR2 film for patient skin dose assessment in cardiac catheterization procedures

Patient skin doses were measured using Kodak EDR2 film for 20 coronary angiography (CA) and 32 percutaneous transluminal coronary angioplasty (PTCA) procedures. For CA, all skin doses were well below 1 Gy. However, 23% of PTCA patients received skin doses of 1 Gy or more. Dose-area product (DAP) was also recorded and was found to be an inadequate indicator of maximum skin dose. Practical compliance with ICRP recommendations requires a robust method for skin dosimetry that is more accurate than DAP and is applicable over a wider dose range than EDR2 film.     

Radiation Exposure of Patients and Interventional Radiologists during Prostatic Artery Embolization: A Prospective Single-Operator Study

Purpose

To prospectively analyze the radiation exposure of patients and interventional radiologists during prostatic artery embolization (PAE).

10种介入诊疗程序中患者的辐射剂量调查

目的 调查研究介入诊疗程序中患者的受照剂量,评估其放射诊疗风险.方法 利用配置有符合IEC 60601-2标准的穿透型电离室的飞利浦Allura Xper FD20 DSA系统,收集记录10种介入诊疗程序共198例患者的剂量参数,估算出可供评估皮肤损伤的最高皮肤剂量及有效剂量.结果 累计透视时间范围为2.1～80.9 min,摄影帧数范围为15～678帧,剂量面积乘积范围为11～825 Gy·cm2,累计剂量范围为24～3374 mGy.有16例患者最高皮肤剂量超过1 Gy,79例患者有效剂量大于20 mSv.结论 有部分病例的最高皮肤剂量超过了皮肤损伤阈值,所以对患者的放射防护应给予足够的重枧.

Abstract：

Objective To investigate radiation dose to the patients undergoing interventional radiology and make radiation risk assessment.Methods Data was collected on 198 instances of 10 interventional radiology procedures by using Philips Allura Xper FD20 DSA, which was equipped with the transparent ionization chamber system in compliance with IEC 60601-2.Patient peak skin dose and effective dose were estimated.Results Cumulative fluoroscopy time was 2.1 - 80.9 min, and number of images monitored for PSD were above 1 Gy and 79 cases monitored for E were above 20 mSv.Conclusions Substantial number of cases exceeded the dose threshold for erythema.Due attention should be paid to radiation protection of patients.     

Local skin and eye lens equivalent doses in interventional neuroradiology

Purpose

To assess patient skin and eye lens doses in interventional neuroradiology and to assess both stochastic and deterministic radiation risks.

Methods

Kerma–area product (P _KA) was recorded and skin doses measured using thermoluminescence dosimeters. Estimated dose at interventional reference point (IRP) was compared with measured absorbed doses.

Results

The average and maximum fluoroscopy times were 32 and 189 min for coiling and 40 and 144 min for embolisation. The average and maximum P _KA for coiling were 121 and 436 Gy cm², respectively, and 189 and 677 Gy cm² for embolisation. The average and maximum values of the measured maximum absorbed skin doses were 0.72 and 3.0 Sv, respectively, for coiling and 0.79 and 2.1 Sv for embolisation. Two out of the 52 patients received skin doses in excess of 2 Sv. The average and maximum doses to the eye lens (left eye) were 51 and 515 mSv (coiling) and 71 and 289 mSv (embolisation).

Conclusion

The ratio between the measured dose and the dose at the IRP was 0.44?±?0.18 mSv/mGy indicating that the dose displayed by the x-ray unit overestimates the maximum skin dose but is still a valuable indication of the dose. The risk of inducing skin erythema and lens cataract during our hospital procedures is therefore small.     

A national patient dose survey and setting of reference levels for interventional radiology in Bulgaria

Objectives

A national study on patient dose values in interventional radiology and cardiology was performed in order to assess current practice in Bulgaria, to estimate the typical patient doses and to propose reference levels for the most common procedures.

Methods

Fifteen units and more than 1,000 cases were included. Average values of the measured parameters for three procedures—coronary angiography (CA), combined procedure (CA?+?PCI) and lower limb arteriography (LLA)—were compared with data published in the literature.

Results

Substantial variations were observed in equipment and procedure protocols used. This resulted in variations in patient dose: air-kerma area product ranges were 4–339, 6–1,003 and 0.2–288 Gy cm² for CA, CA?+?PCI and LLA respectively. Reference levels for air kerma-area product were proposed: 40 Gy cm² for CA, 140 Gy cm² for CA?+?PCI and 45 Gy cm² for LLA. Auxiliary reference intervals were proposed for other dose-related parameters: fluoroscopy time, number of images and entrance surface air kerma rate in fluoroscopy and cine mode.

Conclusions

There is an apparent necessity for improvement in the classification of peripheral procedures and for standardisation of the protocols applied. It is important that patient doses are routinely recorded and compared with reference levels.

Key Points

? Patient doses in interventional radiology are high and vary greatly ? Better standardisation of procedures and techniques is needed to improve practice ? Dose reference levels for most common procedures are proposed     

Skin dose alarm levels in cardiac angiography procedures: is a single DAP value sufficient?

Maximum estimated skin doses to patients undergoing coronary angiography procedures were obtained using radiographic slow film and diode dosemeters. Conversion factors of maximum entrance skin dose versus dose-area product (MESD/DAP) for diagnostic (coronary angiography (CA); 20 patients; 2 operators) and interventional procedures (percutaneous transluminal coronary angiography (PTCA); 10 patients; 1 operator) were 4.3 (mean value of 10 CA; operator A), 3.5 (mean value of 10 CA; operator B) and 9.7 (mean value of 10 PTCA; operator B) mGy(Gycm2)(-1), respectively. The results emphasise a need for both operator- and procedure-specific conversion factors. Compared with a single, global factor for all cardiac procedures and/or operators that is commonly applied today, such a refinement is expected to improve the accuracy in skin dose estimations from these procedures. Consequently, reference DAP values used in the clinic to define patients who could suffer from a radiation induced skin injury following a cardiac procedure, should be defined for each operator/procedure. The film technique was found to be superior to the diode in defining conversion factors in this study, and allowed for a rapid and accurate estimation of MESD for each patient. With appropriate positioning of the diode, a combined film/diode technique has a potential use in the training of new angiography operators. The patient body mass index (BMI) value was a good indicator of the variation in average lung dose (critical organ) between patients. The highest lung dose/DAP value was obtained for normal sized patients (BMI: 19-26), and was close to 1.5 mGy(Gycm2)(-1) with both CA and PTCA procedures.     

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 cm² (II system) and 33 Gy cm² (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.     

Live MR Angiographic Roadmapping for Uterine Artery Embolization: A Feasibility Study

PurposeTo assess the feasibility of live magnetic resonance (MR) angiography roadmapping guidance for uterine artery (UA) embolization (UAE) for fibroid tumors.Materials and MethodsTwenty patients underwent UAE with live MR angiographic roadmapping. The pre-acquired MR angiography scan was coregistered with the live intraprocedural fluoroscopy stream to create a visual roadmap to direct the microcatheter during UAE. Patient radiation dose, as measured by dose–area product (DAP), procedure time, contrast medium volume, and fluoroscopy time, was recorded. For the first 10 patients, an additional parameter of contrast medium volume needed to catheterize each UA was recorded.ResultsIn all 20 patients (40 UAs), the MR angiography overlay on live fluoroscopy was accurate and allowed for successful catheterization of the UA, resulting in a technical success rate of 100%. In the subset of the initial 20 UAs (ie, the first 10 patients) in which this data point was recorded, 17 (85%) were successfully catheterized with no iodinated contrast medium at all, by purely relying on the MR angiography roadmap. Mean procedure time was 45 minutes (range, 30–99 min), mean contrast agent dose was 75 mL (range, 46–199 mL), and mean DAP was 155 Gy·cm² (range, 37–501 Gy·cm²).ConclusionsLive MR angiographic roadmapping is feasible and accurate for catheter guidance during UAE.     

Patient Dose Reference Levels for Interventional Radiology: A National Approach

A set of patient dose reference levels (RLs) for fluoroscopically guided interventional procedures was obtained in a survey launched by the National Society of Interventional Radiology (IR), involving 10 public hospitals, as recommended by the European Medical Exposures Directive. A sample of 1391 dose values (kerma area product [KAP]) was collected randomly during clinical procedures for seven of the most frequent procedures. Third quartiles of the KAP distributions were used to set the RLs. A regular quality control of the X-ray systems and a calibration of the dose meters were performed during the survey. The fluoroscopy time and total number of digital subtraction angiography images per procedure were also analyzed. The RL values proposed were 12 Gy cm² for fistulography (hemodialysis access; sample of 180 cases), 73 Gy cm² for lower limb arteriography (685 cases), 89 Gy cm² for renal arteriography (55 cases), 80 Gy cm² for biliary drainage (205 cases), 289 Gy cm² for hepatic chemoembolization (151 cases), 94 Gy cm² for iliac stent (70 cases), and 236 Gy cm² for uterine embolization (45 cases). The provisional national RL values are lower than those obtained in a similar survey carried out in the United States from 2002 to 2004. These new values could be used to improve the practice of centers consistently working with doses higher than the RLs. This national survey also had a positive impact, as it helped increase the awareness of the members of the National Society of IR on a topic as crucial as patient dose values and programs on radiation protection. This paper was accepted as a scientific poster at the CIRSE annual meeting in Copenhagen, September 2008.     

Radiation Exposure in Nonvascular Fluoroscopy-Guided Interventional Procedures

Purpose

To investigate the radiation exposure in non-vascular fluoroscopy guided interventions and to search strategies for dose reduction.

Materials and Methods

Dose area product (DAP) of 638 consecutive non-vascular interventional procedures of one year were analyzed with respect to different types of interventions; gastrointestinal tract, biliary interventions, embolizations of tumors and hemorrhage. Data was analyzed with special focus on the fluoroscopy doses and frame doses. The third quartiles (Q3) of fluoroscopy dose values were defined in order to set a reference value for our in-hospital practice.

Results

Mean fluoroscopy times of gastrostomy, jejunostomy, right and left sided percutaneous biliary drainage, chemoembolization of the liver and embolization due to various hemorrhages were 5.9, 8.6, 13.5, 16.6, 17.4 and 25.2 min, respectively. The respective Q3 total DAP were 52.9, 73.3, 155.1, 308.4, 428.6 and 529.3 Gy*cm². Overall, around 66% of the total DAP originated from the radiographic frames with only 34% of the total DAP applied by fluoroscopy (P < 0.001). The investigators experience had no significant impact on the total DAP applied, most likely since there was no stratification to intervention-complexity.

Conclusion

To establish Diagnostic Reference Levels (DRLs), there is a need to establish a registry of radiation dose data for the most commonly performed procedures. Documentation of interventional procedures by fluoroscopy “grabbing” has the potential to considerably reduce radiation dose applied and should be used instead of radiographic frames whenever possible.     

Radiation dose to the operator during fluoroscopically guided spine procedures

Purpose

Fluoroscopy is widely used to guide diagnostic and therapeutic spine procedures. The purpose of this study was to quantify radiation incident on the operator (operator Air Kerma) during a wide range of fluoroscopy-guided spine procedures and its correlation with the amount of radiation incident on the patient (Kerma Area Product—KAP).

Methods

We retrospectively included 57 consecutive fluoroscopically guided spine procedures. KAP [Gy cm²] and total fluoroscopy time were recorded for each procedure. An electronic dosimeter recorded the operator Air Kerma [μGy] for each procedure. Operator Air Kerma for each procedure, correlation between KAP and operator Air Kerma, and between KAP and fluoroscopy time was obtained.

Results

Operator Air Kerma was widely variable across procedures, with median value of 6.4 μGy per procedure. Median fluoroscopy time and median KAP per procedure were 2.6 min and 4.7 Gy cm², respectively. There was correlation between operator Air Kerma and KAP (r ² = 0.60), with a slope of 1.6 μGy Air Kerma per unit Gy cm² KAP incident on the patient and between fluoroscopy time and KAP (r ² = 0.63).

Conclusion

Operator Air Kerma during individual fluoroscopy-guided spine procedures can be approximated from the commonly and readily available information of the total amount of radiation incident on the patient, measured as KAP.

     

Importance of a Patient Dosimetry and Clinical Follow-up Program in the Detection of Radiodermatitis After Long Percutaneous Coronary Interventions

Purpose

Complex percutaneous interventions often require high radiation doses likely to produce skin radiation injuries. We assessed the methodology used to select patients with potential skin injuries in cardiac procedures and in need of clinical follow-up. We evaluated peak skin dose and clinical follow-up in a case of radiodermatitis produced during a total occlusion recanalization.

Materials and Methods

This prospective study followed CIRSE and ACC/AHA/SCAI recommendations for patient radiation dose management in interventional procedures carried out in a university hospital with a workload of 4200 interventional cardiac procedures per year. Patient dose reports were automatically transferred to a central database. Patients exceeding trigger levels for air kerma area product (500 Gy cm²) and cumulative skin dose (5 Gy) were counseled and underwent follow-up for early detection of skin injuries, with dermatologic support. The Ethical Committee and the Quality Assurance and Radiation Safety Committee approved the program.

Results

During 2010, a total of 13 patients (3.0/1,000 that year) received dose values exceeding trigger levels in the cardiovascular institute. Only one patient, who had undergone two consecutive procedures resulting in 970 Gy cm² and 13.0 Gy as cumulative skin dose, showed signs of serious radiodermatitis that resolved in 3.7 months. The remaining patients did not manifest skin lesions during follow-up, and whenever patient examination was not feasible as part of the follow-up, neither patients nor families reported any skin injuries.

Conclusions

Peak skin dose calculation and close clinical follow-up were feasible and appropriate, with a moderate additional workload for the staff and satisfaction for the patient.     

Reference levels and patient doses in interventional cardiology procedures in Greece

Objectives

To present a national survey that was performed for the establishment of national reference levels (RLs) for interventional cardiology (IC) procedures and to estimate the effective dose (E) received by the patient during these procedures.

Methods

Data concerning the fluoroscopy time and air kerma-area product (P _KA) during coronary angiography (CA), percutaneous coronary intervention (PCI), pacemaker implantation (PMI) and radiofrequency cardiac ablation (RFCA) from 26 centres were collected. Moreover, measurements concerning the performance of X-ray systems used in IC were performed in order to set system-related reference levels. P _KA to E conversion factors were also calculated.

Results

The suggested P _KA RLs for CA, PCI, PMI and RFCA are 53 Gycm², 129 Gycm², 36 Gycm² and 146 Gycm², respectively, and the estimated E to the patient from these procedures is 9.7 mSv, 26.8 mSv, 5.5 mSv and 20.4 mSv, respectively. Reference levels for the fluoroscopic dose rate and dose per frame during image acquisition at the entrance of a water phantom are 29 mGy/min and 0.23 mGy/frame, respectively.

Conclusions

The suggested RLs are comparable to those suggested by other studies. Additional information concerning the complexity of the procedures and patient pathology should be collected for future reevaluation of the suggested RLs.

Key Points

? The radiation dose imparted during fluoroscopically guided interventional procedures can be high ? Understanding of reference levels might help optimise interventional cardiological procedures ? Optimisation by changing the systems’ settings seems feasible in some cases ? Procedure complexity and the patient’s clinical problem should be taken into account     

Comparison of a conventional and a flat-panel digital system in interventional cardiology procedures

The purpose of the study was to analyse the technical characteristics of a newly installed flat-panel fluoroscopy (FPF) system in an interventional cardiology (IC) department and compare it with an older conventional system. A patient survey was performed to investigate the radiation doses delivered by the X-ray systems. Finally, methods of technique optimization regarding the new digital system were investigated. Dose rates in all fluoroscopic and cine modes were measured and image quality assessed using a dedicated test tool. 200 patients were investigated, half using the conventional and half using the digital FPF system. Patient data collected were: sex, age, weight, height, dose-area product (DAP), fluoroscopy time (T) and total number of frames (F). Our results are: (1) Digital FPF system: high contrast resolution (HCR) is not affected by fluoroscopic mode, whereas low contrast resolution (LCR) is slightly decreased in the low mode. (2) The digital FPF system has 2.5 times better HCR than the conventional system, with 5 times lower dose in the fluoroscopy mode. (3) Median values of DAP, T and F, respectively, in coronary angiography (CA) are: 27.7 Gycm(2), 4.1 min and 876 for the digital and 39.3 Gycm(2), 5.3 min and 1600 for the conventional system. Median values for percutaneous transluminal coronary angioplasty (PTCA) are: 51.1 Gycm(2), 12.7 min and 1184 for the digital and 44.3 Gycm(2), 7.4 min and 1936 for the conventional system. Digital DAP in CA is reduced by 30%, suggesting that a dose reduction in the FPF system is possible. The results of the study concerning the FPF system lead to the conclusion that the lowest fluoroscopic mode and the lowest frame rate should be used in routine practice.