Safety guideline

Guidelines for Patient Radiation Dose Management

Concerns surrounding the consequences of ionizing radiation (IR) have increased in interventional cardiology (IC). Despite this, the ever-growing complexity of diseases as well as procedures can lead to greater exposure to radiation. The aim of this survey, led by Portuguese Association of Interventional Cardiology (APIC), was to evaluate the level of awareness and current practices on IR protection among its members.

An online survey was emailed to all APIC members, between August and November 2021. The questionnaire consisted of 50 questions focusing on knowledge and measures of IR protection in the catheterization laboratory. Results were analyzed using descriptive statistics.

From a response rate of 46.9%, the study obtained a total sample of 159 responses (156 selected for analysis). Most survey respondents (66.0%) were unaware of the radiation exposure category, and only 60.4% reported systematically using a dosimeter. A large majority (90.4%) employed techniques to minimize exposure to radiation. All participants used personal protective equipment, despite eyewear protection only being used frequently by 49.2% of main operators. Ceiling suspended shields and table protectors were often used. Only two-thirds were familiar with the legally established limit on radiation doses for workers or the dose that should trigger patient follow-up. Most of the survey respondents had a non-certified training in IR procedures and only 32.0% had attended their yearly occupational health consultation.

Safety methods and protective equipment are largely adopted among interventional cardiologists, who have shown some IR awareness. Despite this, there is room for improvement, especially concerning the use of eyewear protection, monitoring, and certification.

A preocupação com as consequências da radiação ionizante tem vindo a crescer na cardiologia de intervenção. O objetivo da Associação Portuguesa de Cardiologia Interventiva (APIC) foi avaliar o nível de sensibilização e práticas atuais na proteção contra a radiação ionizante.

Um inquérito voluntário foi enviado por e-mail aos membros da APIC, entre Agosto-Novembro de 2021, que consistiu em 50 questões relativas ao conhecimento e medidas de proteção contra a radiação. Posteriormente foi efetuada a respetiva análise descritiva.

Obtiveram-se 159 respostas (46,9% do inquérito enviado) - 156 foram consideradas adequadas para análise. A maioria (66,0%) desconhecia a categoria de exposição à radiação correspondente e apenas 60,4% utilizaram o dosímetro de forma sistemática. 90,4% dos inquiridos utilizaram técnicas para minimizar a exposição à radiação. Praticamente todos os participantes utilizaram equipamento de proteção individual, mas a proteção ocular apenas ocorreu de forma frequente em 49,2% dos operadores principais. Escudos de teto e protetores de mesa foram os materiais disponíveis mais utilizados. Apenas dois terços conheciam a dose limite legalmente estabelecida para os trabalhadores ou a dose que deve desencadear um acompanhamento do paciente. A maioria dos inquiridos tinha uma formação não certificada em radiação ionizante e apenas 32,0% tiveram consulta anual de medicina do trabalho.

A consciencialização e as práticas adotadas para proteção contra radiação ionizante têm vindo a aumentar entre os profissionais de cardiologia de intervenção. Ainda assim, existe espaço para melhorar, nomeadamente no uso da proteção ocular, necessidade de monitoração e certificação.

Endovascular treatment is continuously gaining ground in vascular surgery procedures. However, current patient radiation dose estimation does not take into account the exact patient morphology and organs' composition. Monte Carlo (MC) simulation can accurately estimate the dose by recreating the irradiation process generated during X-ray-guided interventions. This study aimed to validate the MC simulation models by comparing simulated and measured dose distributions in endovascular aortic aneurysm repair (EVAR) procedures.

We conducted a clinical study in patients treated for EVAR. Patient dose measurements were taken with passive dosimeters using Optically Stimulated Luminescence technology in 4 specific anatomical points on the skin: xiphoid process, pubic symphysis, right and left iliac crest. Dose measurements were compared to the corresponding simulated doses with the Geant4 Application for Emission Tomography (GATE) and GPU Geant4-based Monte Carlo Simulations (GGEMS) MC simulations softwares. The MC simulation took as input the computed tomography scan of the patient and the parameters of the imaging system (orientation angles, tube voltage, and aluminum filtration) and gives as output the three-dimensional (3D) dose map for each patient and angulation.

A good agreement with real doses was found for doses simulated by the MC GATE method (P < 0.0001; r = 0.97; 95% confidence interval [CI] [0.96–0.98]), as well as for doses simulated by the GGEMS method (P < 0.0001; r = 0.96; 95% CI [0.94–0.97]). The mean relative error for all measurements was 5 ± 5% in the MC GATE group and 6 ± 5% in the GGEMS group. Process execution on GGEMS (6 sec) was faster than the GATE MC simulation (5 hr).

Considering the current imaging settings, this study shows the potential of using the GATE and GGEMS MC simulations platforms to model the 3D dose distributions during EVAR procedures.

Fluoroscopically-guided neurointervention may be associated with prolonged procedure time and substantial radiation exposure to the patient and staff. This study sought to examine technological features affecting the potential radiation exposure reduction of new angiography systems, compared to older systems, for neurointerventional procedures.

Consecutive neurointerventional patients (2020–2022) were retrospectively analyzed. The air kerma at the reference point (K_a,r) and kerma-area product (KAP) were compared between Artis icono and Artis zee (Siemens) using statistical analyses (two-tailed t tests), where P < 0.05 is considered significant. X-ray tube potential and copper filtration were examined. Tests with an anthropomorphic phantom (Sun Nuclear) on Artis icono were conducted and entrance skin exposure and x-ray spectral half value layer were measured. Effective spectral filtration was characterized by x-ray spectral modeling.

The number of procedures was 1158 [median (range) age, 59 (7–95) years] on Artis zee and 1087 [60 (1–95) years] on Artis icono, without significant difference in age (p = 0.059) between cohorts. K_a,r was 925.4 (890.6–960.1) mGy [mean (95 % CI)] and KAP was 119.8 (115–124.5) Gy∙cm² on Artis zee. The measures were 48–50 % lower on Artis icono, 440.5 (411.7–469.4) mGy (K_a,r) and 59.5 (55.4–63.6) Gy∙cm² (KAP); while the difference in fluoroscopic time between the two generations of angiography systems was insignificant (p = 0.55).

The newer angiography system, with updated hardware and software, was found to result in half the radiation exposure compared to older technology of the same manufacturer, even though fluoroscopic time was similar.

Multimodal imaging is the incorporation of two or more imaging modalities during the same examination, and it has both diagnostic and treatment applications. The use of image fusion for intraoperative guidance in endovascular interventions is being extended increasingly to the field of vascular surgery, especially in the context of hybrid operating rooms. The aim of this work was to perform a review and narrative synthesis of the available literature in order to report on current applications of multimodal imaging in diagnosis and treatment of emergent vascular conditions. Of 311 records selected in the initial search, 10 articles were included in the present review: 4 cohort studies and 6 case reports. The authors have presented their experience in treating ruptured abdominal aortic aneurysms; aortic dissections; traumas; standard endovascular aortic aneurysm repair, with or without deterioration of renal function; and complex endovascular aortic aneurysm repair, and reported on the long-term clinical results. Although the current literature about multimodal imaging application in emergency vascular conditions is limited, this review highlights the potential of image fusion in hybrid angio-surgical suites, especially for diagnosing and performing treatment in the same operating room, avoiding patient transfer, and allowing procedures with zero or low-dose contrast mean.

In the present study, we have described the technical success using Fiber Optic RealShape (FORS) endovascular guidance and its effects on the overall procedural time and radiation usage during complex endovascular aortic repair (EVAR).

Fenestrated and branched EVARs performed at a single center from 2017 to 2022 were prospectively studied. FORS-guided procedures were matched retrospectively 1:3 to non–FORS-guided procedures by the incorporated target arteries and body mass index. Technical success was defined as successful target vessel cannulation using FORS for the entirety of navigation (wire insertion to exchange for a stiff wire). The predictors of technical success were evaluated via logistic regression. The procedural times and radiation doses were compared between the matched cohorts using the Wilcoxon rank sum test.

A total of 21 FORS-guided procedures were matched to 61 non–FORS-guided procedures. A total of 95 FORS cannulations were attempted (87 for the visceral target artery and 8 for the bifurcate gate). Technical success was achieved in 81 cannulations (85%); 15 (16%) were completed without the use of live fluoroscopy. The univariate predictors of FORS technical success included <50% target artery stenosis, <50% target artery calcification, and the target vessel attempted (P < .05 for each). FORS failures were attributed to device material properties in six cases, device failure in two cases, and the wire/catheter combination in six. The use of FORS guidance was associated with shorter median procedural and fluoroscopy times and a lower dose area product and air kerma (P ≤ .0001 for each).

The results from our initial experience with FORS during complex EVAR, including our learning curve, has shown promise, with acceptable technical success and reductions in procedural times and radiation usage.

Patient skin dose from interventional fluoroscopy procedures may exceed the threshold of tissue injuries and established guidelines recommend patient follow-up for air kerma at reference point (K_a,r) ≥ 5 Gy for individual procedures. Patients may undergo multiple procedures and skin injuries may be possible by cumulative exposure, even when individually insufficient to cause injury. This study sought to quantify the frequency of patients whose individual procedure doses are below 5 Gy but whose cumulative K_a,r is ≥ 5 Gy.

This retrospective study analyzed 37,917 consecutive procedures in interventional radiology and vascular surgery at a tertiary-care hospital between January 2016 and June 2021. Radiation dosage was retrieved from the fluoroscopy acquisition systems. For a patient receiving multiple procedures, but each with K_a,r < 5 Gy, cumulative K_a,r within 2, 7, 14, 30, 183, and 365 days was assessed.

Nearly 1/3rd (37.4 %) patients underwent multiple procedures. With individual procedures of K_a,r < 5 Gy exclusively, 1.9, 4.4, and 5.6 in 1000 patients received cumulative K_a,r of 5–14.1 Gy from the procedures within 30, 183, and 365 days, respectively. From the procedures within 14 days, 1.3 in 1000 patients received cumulative K_a,r of 5–11.4 Gy; and from those within 7 days, 0.87 in 1000 patients received 5–9.1 Gy. In comparison, 4.3 in 1000 patients received K_a,r of 5–12 Gy from a single procedure.

In the absence of guidelines on patient follow-up for multiple procedures, our study may provide good material for setting up such guidelines.