Radiation dose optimization in coronary angiography and percutaneous coronary intervention (PCI). II. Clinical evaluation

In a previous part of this study, the fluoroscopy dose rate was reduced in a cardiac catheterization laboratory. The objectives of the present study were to evaluate the effects in a clinical population undergoing percutaneous coronary intervention (PCI) of the dose-reducing measures detailed previously. Kerma area-product (KAP) values were first recorded for 154 patients undergoing PCI. Then, the fluoroscopy KAP rate was reduced from 44 to 16 mGy cm²/s by increasing filtration and reducing the image intensifier dose request. After this optimization, KAP was recorded for another 138 PCI procedures. After adjustment for differing proportions of combined procedures (coronary angiography+PCI), the total KAP was reduced to 67% of the original value with a 95% confidence interval from 57 to 78%, statistically significant. The mean total KAP values were 93.6 Gy cm² before and 69.1 Gy cm² after optimization. The KAP for digital acquisition did not change significantly. It is possible to make a large dose reduction in PCI by reducing the fluoroscopy dose rate. This dose reduction is beneficial for both patients and staff. Electronic Publication     

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。     

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.     

旋转造影与标准造影术患者辐射剂量比较

目的 比较双轴旋转造影（RA）与传统标准造影（SA）时患者所受辐射剂量。方法 采用同一拟人模体模拟临床条件下的冠状动脉造影。根据不同造影模式,实验分为RA组和SA组,根据不同电影时间,SA组又分为2 s组（SA1）、3 s组（SA2）、5 s组（SA3）3个亚组。造影操作使用机器预设程序自动调节造影体位并控制透视及造影时间,每组均使用同一模体重复操作10次完整造影,采用TLD 3×3矩阵和造影机随机配备的射线剂量仪同时记录辐射剂量,后者可记录剂量面积乘积（DAP）和空气比释动能（AK）,每组数据重复测量10次取均值进行比较。结果 完成整个造影操作,RA组累计DAP、AK均值分别为3 061.6 mGy·cm²和64.2 mGy,低于SA1组（4 213.9 mGy·cm²和85.5 mGy）、SA2组（6 436.0 mGy·cm²和112.2 mGy）、SA3组（12 810.4 mGy·cm²和243.7 mGy）。RA组累计皮肤入射剂量的均值（37.70 mGy）高于SA1组（26.56 mGy）,但低于SA2组（46.86 mGy）、SA3组（77.79 mGy）。SA中3个亚组TLD剂量最大点与剂量最小点差异十分显著,而RA组剂量分布相对平均。结论 双轴旋转造影与传统标准造影相比,患者的累计辐射剂量显著降低,在一定程度上避免了皮肤损伤。     

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.

     

心血管介入手术中透视时间作为辐射剂量警示指标的可行性研究

目的以心血管介入术后采集空气比释动能(reference air kerma,AK)值和剂量面积乘积(dose-area product,DAP)值数据为依据,分析术中透视时间报警设置作为心血管介入手术辐射剂量的监测和警示工具的可行性。方法回顾性分析2016年11月至2018年1月上海长海医院736例冠状动脉造影术(CAG)和经皮冠状动脉治疗术(PCI)病例,收集术中透视时间、AK和DAP数据资料。德国西门子成像设备分组(Ceiling系统和Biplane系统)和手术类型分组(CAG和PCI),对辐射剂量数据进行比较,以及对心血管介入手术AK和DAP值与透视时间数据采用Spearman检验解析相关性。结果Ceiling和Biplane成像系统中手术透视时间为(8.9±7.8)和(8.6±7.3)min,透视AK均值和DAP均值分别为(472±474)、(510±509)mGy、(4548±4085)和(4255±3781)μGy·m^2,术中总(透视+造影)AK和DAP均值为(703±595)、(733±614)mGy、(6253±4938)和(5681±4432)μGy·m^2。CAG与PCI术中透视时间均值分别为(2.4±0.9)和(15.7±4.9)min。PCI透视辐射剂量(AK和DAP)与术中总辐射剂量比值分别为74%和78%。心血管介入手术中透视时间与AK值(r=0.822)和DAP值(r=0.844)都呈高度相关性(P<0.001)。结论透视采集辐射剂量是心血管介入手术中辐射剂量的主要来源,辐射剂量随透视时间延长而增加,透视时间监测和报警设置在心血管介入临床应用中作为术中辐射防护工具有一定的参考和警示价值。     

Radiation Dose in Prostatic Artery Embolization Using Cone-Beam CT and 3D Roadmap Software

PurposeTo evaluate the radiation dose in patients undergoing prostatic artery embolization (PAE) using cone-beam CT and 3-dimensional (3D) guidance software.Materials and MethodsIn this single-center retrospective study, 100 patients with benign prostatic hyperplasia (mean prostate volume, 83.6 mL ± 44.2; 69.4 ± 9.6 years of age; body mass index, 26.5 ± 4.2) were treated using PAE between October 2016 and April 2018. Informed consent was obtained from all participants included in the study. All patients received at least 1 intraprocedural cone-beam CT per side for evaluation of the vessel anatomy and software rendering of 3D guidance for catheter guidance. Digital subtraction angiography (DSA) was performed in the distal branches only. The total dose area product (DAP), along with the DAP attributed to fluoroscopy, DSA, and cone-beam CT, were assessed.ResultsBilateral embolization was achieved in 83 patients (83%). The average total DAP was 134.4 Gy ⋅ cm² ± 69.5 (range, 44.7–410.9 Gy ⋅ cm²). Fluoroscopy, DSA, and cone-beam CT accounted for 35.5 Gy ⋅ cm² ± 21.3 (range, 8.6–148.6 Gy ⋅ cm²) or 26.4% (percentage of total DAP), 58.2 Gy ⋅ cm² ± 48.3 (range, 10.3–309.3 Gy ⋅ cm²) or 43.3%, and 40.7 Gy ⋅ cm² ± 14.5 (range, 15.9–86.3 Gy ⋅ cm²) or 30.3%, respectively. Average procedure time was 89.4 ± 27.0 minutes, and the average fluoroscopy time was 30.9 ± 12.2 minutes.ConclusionsIntraprocedural cone-beam CT in combination with 3D guidance software allows for identification and catheterization of the prostatic artery in PAE. Furthermore, the results of this trial indicate that this study protocol may lead to a low overall radiation dose.     

3D cerebral angiography: radiation dose comparison with digital subtraction angiography

BACKGROUND AND PURPOSE: As the use of 3D rotational angiography (3D RA) for the evaluation of cerebral vasculature becomes more widespread, it is important to evaluate this imaging method's effect on patient radiation dose. The purpose of the study is to measure 3D RA radiation dose as compared with biplanar digital subtraction angiography (DSA). METHODS: The distribution and peak skin dose were measured for 3D RA and biplanar DSA by using an anthropomorphic skull phantom. In addition, the cumulative incident dose, summed over all images in each acquisition, was determined. Measurements were acquired for our facility's standard 3D RA acquisition mode (25 degrees /s rotational speed; 162 total frames) and other available acquisition mode selections. RESULTS: For 3D RA, the skin dose was found to be distributed across the back and sides of the skull with the peak skin dose located at the center of the back of the skull. The peak skin dose for the standard 3D RA acquisition mode was 15 mGy. For a biplanar DSA run, the peak skin dose was 58 mGy, also located at the back of the skull. The cumulative incident dose for the standard 3D RA acquisition mode was 33 mGy, compared with 53 mGy for biplanar DSA. CONCLUSION: The patient radiation dose for 3D RA is significantly lower than for biplanar DSA, by nearly a factor of 4 in peak skin dose and 40% lower in cumulative incident dose.     

Dynamic swallowing study and radiation dose to patients

PURPOSE: The purpose of this study was to define an optimal radiological procedure to evaluate the results of rehabilitation therapy for swallowing disorders and to calculate both the effective and organ dose to the patient to provide a measure of the radiation risk associated with the procedure. MATERIALS AND METHODS: In order to define the optimal radiological procedure, kerma-area product (KAP) measurements and evaluations of image quality in fluoroscopy and fluorography mode were made using dedicated phantoms. Twenty-two patients were included in the study, and the values of KAP, screening time and average voltage selected were individually recorded. The recorded KAP values were used to estimate radiation risk with the use of dedicated calculation software. RESULTS: Median, first and third quartiles of the KAP distribution were, respectively, 2.1, 1.5 and 2.7 Gy cm2, with a corresponding effective dose of 0.35, 0.26 and 0.46 mSv. A good correlation between KAP and exposure time was also found (R2=0.85). Exposure of the thyroid, which is inside the radiation field, accounts for the greatest share to the effective dose, with a calculated median dose of 6 mGy. CONCLUSIONS: With the defined radiological procedure, the obtained KAP values are lower than recorded doses in interventional radiology, and the corresponding values of entrance skin dose are lower than the threshold dose for deterministic effects. Considering the effective dose at the median KAP value, the probability for stochastic effects is shown to be low, at approximately 1 in 39,000.     

Radiation Dose Reduction during Uterine Fibroid Embolization Using an Optimized Imaging Platform

Purpose

To assess radiation dose reduction during uterine fibroid embolization (UFE) using an optimized angiographic processing and acquisition platform.

Fetal Radiation Dose in Prophylactic Uterine Arterial Embolization

Purpose

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.

Methods

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 (T_f), and dose rate also was recorded.

Results

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) cGy cm², ESE 120 (63–184) mGy, T_f 7:31 (5:05–11:35) min:sec, and dose rate 15 (8–21) mGy/min, respectively.

Conclusions

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.     

Low-Dose Three-Dimensional Rotational Angiography for Evaluating Intracranial Aneurysms: Analysis of Image Quality and Radiation Dose

ObjectiveThis study aimed to evaluate the image quality and dose reduction of low-dose three-dimensional (3D) rotational angiography (RA) for evaluating intracranial aneurysms.Materials and MethodsWe retrospectively evaluated the clinical data and 3D RA datasets obtained from 146 prospectively registered patients (male:female, 46:100; median age, 58 years; range, 19–81 years). The subjective image quality of 79 examinations obtained from a conventional method and 67 examinations obtained from a low-dose (5-seconds and 0.10-µGy/frame) method was assessed by two neurointerventionists using a 3-point scale for four evaluation criteria. The total image quality score was then obtained as the average of the four scores. The image quality scores were compared between the two methods using a noninferiority statistical testing, with a margin of -0.2 (i.e., score of low-dose group – score of conventional group). For the evaluation of dose reduction, dose-area product (DAP) and air kerma (AK) were analyzed and compared between the two groups.ResultsThe mean total image quality score ± standard deviation of the 3D RA was 2.97 ± 0.17 by reader 1 and 2.95 ± 0.20 by reader 2 for conventional group and 2.92 ± 0.30 and 2.95 ± 0.22, respectively, for low-dose group. The image quality of the 3D RA in the low-dose group was not inferior to that of the conventional group according to the total image quality score as well as individual scores for the four criteria in both readers. The mean DAP and AK per rotation were 5.87 Gy-cm² and 0.56 Gy, respectively, in the conventional group, and 1.32 Gy-cm² (p < 0.001) and 0.17 Gy (p < 0.001), respectively, in the low-dose group.ConclusionLow-dose 3D RA was not inferior in image quality and reduced the radiation dose by 70%–77% compared to the conventional 3D RA in evaluating intracranial aneurysms.     

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).

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.     

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.     

Radiation dose optimization in coronary angiography and percutaneous coronary intervention (PCI). I. Experimental studies

The objectives of this study were to evaluate the influence on image quality and dose to the patient and operator of various equipment settings for percutaneous coronary intervention (PCI), and to optimize the set-up. With an Alderson phantom, different settings, such as projection, protective screens, filtration, image intensifier size and collimation, were evaluated. Kerma-area product (KAP) was recorded as a measure of patient dose and scattered radiation was measured with an ionization chamber. Effective dose for a standardized PCI procedure was measured with thermoluminescent dosimeters inside the phantom. Image quality was evaluated with a contrast-detail phantom. Based on these findings, the equipment set-up was optimized to a low fluoroscopy dose rate with a sufficient image quality. Several operating parameters affected dose, particularly scattered radiation. The optimization reduced the fluoroscopy KAP rate from 44 to 16 mGy cm(2)/s using 15 cm of acrylic. The effective dose was reduced from 13 to 4.6 mSv for a standardized PCI procedure. Radiation dose to patient and operator in PCI is heavily dependent on both equipment set-up and operating parameters which can be influenced by the operator. With a careful optimization, a large reduction of radiation dose is possible.     

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.     

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.     

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