A voluntary and anonymous questionnaire (Supplement S1) was emailed to all registered APIC members between August and November 2021. The questionnaire consisted of 50 questions, including demographics as well as four main topics: knowledge surrounding IR; techniques and methods used to minimize exposure to IR; equipment used to protect against IR; awareness/prevention on the effects of IR. Inclusion criteria were being an active member of APIC, and currently employed in an IC role. For the purpose of this study, the IC team was composed of the following members: main operator – interventional cardiologist who performs the procedures as the first operator; assistant operator – interventional cardiologist/interventional cardiology fellow/cardiology fellow or cardiorespiratory technician/nurse who is an intervention assistant on the intervention table; room assistant – cardiorespiratory or radiology technician/nurse whose function is to assist the team that is on the intervention table (for example as a circulating nurse or scrub assistant).

Data were cleaned and a descriptive analysis was subsequently performed. Categorical variables are presented as frequencies and percentages, and continuous variables as means and standard deviations, or medians and interquartile ranges for variables with skewed distribution or a significant Shapiro–Wilk test. Statistical analysis was performed with SPSS Inc., Chicago, IL, USA, version 21.0.

Most of the survey respondents were male (81 of 156, 51.9%), aged between 30 and 49 years (62.2%). Physicians were the most represented class, accounting for 67 of 156 (42.9%), from which 61 (39.1%) were main operators (only six doctors were considered assistant operators). Radiation exposure reflected by a higher time experience in Cath-Lab for over 20 years was present in 49 (31.4%) participants. Most responses were from professionals based in the Greater Lisbon area (63 of 156, 40.4%), although all regions were represented (Table 1).

These questions aimed to assess the level of knowledge regarding IR, as well as understanding the different forms of monitoring used by the sample (Supplement S1, Table 1).

Most survey respondents were unaware of what type of occupational radiation exposure category they belonged to (103 of 156, 66.0%), with older participants mostly in category A (27 of 96, 28.7%). The vast majority of participants were monitored dosimetrically (150 of 156, 96.2%), despite only 60.4% (93 of 154) participants reporting a systematic use of the dosimeter. Full body monitoring was the most used approach by all participants (131 of 143, 91.6%). Almost a third of main operators also used a ring for radiation monitoring (15 of 53, 28.3%) (Figure 1). Dosimeter reading was performed monthly in 100 (64.9%) survey respondents. Exposure in more than one entity (54 of 156, 34.6%), as well as communication between them (13 of 82, 30.5%), was not a usual practice.

Figure 1.

Type of individual monitoring used by main operators (%) (53 responses).

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Most participants had access to dose recordings (117 of 155, 75.5%) and had not been previously called due to exceeding occupational dose limits (131 of 155, 84.5%). The majority knew the legally defined dose limits (100 of 155, 64.5%), as well as the need for mandatory notification in case of pregnancy (123 of 156, 78.8%), but were not aware of the trigger levels that determine the need for exposed patient follow-up (102 of 156, 65.4%).

Having received training in radiation protection was reported by 104 of 156 (66.7%) survey respondents, but this was mainly informal training. Academic (formal) training was more commonly reported by younger participants (14 of 33, 42.4%) (Figure 2).

Figure 2.

Type of training in radiation protection (%) (103 responses).

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Questions focusing on safety methods aimed to assess the use of techniques in clinical practice that minimize IR exposure (Supplement S1, Table 2).

Most participants used techniques to minimize exposure to IR (141 of 156, 90.4%). Optimization of the interventional table and detector position were reported to be always used by 36 of 58 (62.1%) main operators. Fluoroscopy optimization and collimation were also frequently adopted by main operators (always or often in 68.4% and 65.5%, respectively). Distance to the radiation source was less frequently adopted by main operators (Figure 3) (details in Supplement S1, Table 2.1). IC operators mostly used low-dose protocols (total sample: 120 of 156, 76.9%; main operators: 48 of 61, 78.7%), favored a pulse rate of 7.5 pulse/second (p/s) during fluoroscopy (total sample: 71 of 128, 55.5%; main operators: 31 of 56, 55.4%) and a frame rate of 15 frame/second (f/s) in cinefluorography (total sample: 51 of 130, 39.2%; main operators: 28 of 56, 50.0%).

Figure 3.

Techniques used by main operators to minimize exposure to ionizing radiation and frequency (%) (58 responses).

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Almost a quarter reported having finished a procedure by reaching a radiation dose greater than tolerated levels (total sample: 42 of 156, 26.9%; main operators: 17 of 61, 27.9%), mainly when performing a CTO.

When not involved in direct patient contact, 96.5% (110 of 114) of survey respondents would follow specific room positioning within the Cath-Lab, with most favoring the bottom of the patient's table (81 of 112, 72.3%).

One section of the questionnaire also aimed to ascertain the access to and availability of radiological protection and its use within the Cath-Lab (Supplement S1, Table 3).

All participants reported using personal radiation protection equipment, mainly thyroid protectors and aprons (96.2%). Head and eye protections (32 of 123, 26.0%) and arms/hands and legs protections (5 of 88, 5.7%) were used less often (Figure 4). Despite largely available, eye protection with glasses/visors was seldom used (glasses: always and often in 50 of 127, 39.4%; visors: always and often in 6 of 91, 6.6%; glasses and visors: always and often in 56 of 156, 35.9%), and this was also reported when evaluating the main operators only (glasses: always and often in 26 of 58, 44.8%; visors: always and often in 4 of 45, 8.8%; glasses and visors: always and often in 30 of 61, 49.2%) (Supplement S1, Table 3.1). Protective gloves were frequently not used by survey respondents (only 3 of 44 main operators used, 6.8%). Beanies, gloves, sleeves, and boots were the radiation protection equipment least available by the Cath-Labs (Supplement S1, Figure 1).

Figure 4.

Types of radiological protection equipment used and frequency (%).

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Most Cath-Labs provided additional radiation protections (Figure 5) including suspended ceiling shield, table with pelvic protection and portable barrier, frequently used (Supplement S1, Figure 2).

Figure 5.

Types of accessories provided by the Cath-Labs to complement radiation protection (%) (150 responses).

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The survey also assessed the awareness of participants regarding IR exposure, as well as determining the regularity of occupational health reviews (Supplement S1, Table 4).

Most survey respondents had attended at least one occupational health consultation (104 of 156, 66.7%), but only 39 of 122 (32.0%) reported a yearly attendance. Lens evaluation during occupational health review was reported by 28 of 134 (20.6%) of participants, and only one participant had been referred for an ophthalmology review. General investigations such as thyroid function tests, chest radiograph and electrocardiogram were usually included in the occupational health review (Table 2).

The majority of survey respondents had concerns regarding the exposure to radiation by operators (150 of 156, 96.2%) and patients (141 of 156, 90.4%) during procedures. Overall, the concern was high (Figure 6).

Figure 6.

Quantification of concern about the radiation the patient (a) and the operator (b) are exposed to, compared according to age (1-low to 5-high) (146 responses).

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For monitoring and surveillance, there are two categories of exposed workers:

• •

  category A: workers who are liable to receive an effective dose of 20 mSv per year averaged over five consecutive years (100 mSv in 5 years) and of 50 mSv in any single year; an equivalent dose to the lens of the eye of 20 mSv per year averaged over five consecutive years (100 mSv in 5 years) and of 50 mSv in any single year; an equivalent dose to the extremities (hands and feet) or to the skin of 500 mSv in a year, and

• •

  category B: workers who are not classified as A.3,13,14

Knowledge of these categories is crucial for the understanding of the suitability (and safety) for any given radiation dose exposure.

In the present survey, most of the workers did not know to which category they belonged (66.0%). This is also important in defining the periodicity of dosimeter readings (monthly in category A and quarterly in category B).13 A total of 64.9% of the survey respondents reported monthly readings, which should be equivalent to the true percentage of workers in category A.

The use of dosimeters should be systematic, which is not the case for about 40.0% of the survey respondents. Only two-thirds of participants knew the legally established limits for workers (50 mSv in any single year), as well as the exposure that should trigger patient follow-up due to possible tissue reactions (cumulative air kerma (Ka,r) of 5000 mGy or air kerma-area product (PKA) of 500 Gy cm2).15 Any pregnant or breastfeeding professional must report to the occupational health team, and may not perform functions involving a significant risk (should not exceed 1 mSv during pregnancy).4,13,16 The majority of participants appear to be aware of these regulations. Certified IR training is recommended to all team members, but this appears to be lacking in the majority of survey respondents.1,13

Methods and techniques to minimize radiation exposure were often used (90.4%), albeit “as low as reasonably achievable” (ALARA). The use of collimation and the reduced distance between the patient and the image detector (raised table, low detector) was widely used by the survey respondents (main operators). Collimation reduces the irradiated volume, the overall patient dose and scatter radiation, and this parameter directly affects PKA.1,17 In addition, guidelines also advise the use of “store-fluoro” option and to avoid angled projections, techniques to minimize IR that can potentially be used more often in Portuguese Cath-Labs.1,17

The use of low-dose protocols is important to minimize exposure, as was the case for 76.9% of survey respondents. Low-rate fluoroscopy at 7.5 p/s is a very effective measure to reduce both operator and patient radiation exposure, without significant effect on procedure duration, fluoroscopy time or contrast use. A reduction from 15 p/s to 7.5 p/s with a low-dose fluoroscopy mode minimizes radiation exposure by 67%.1,8,9,18–20 It is important to highlight that most main operators used fluoroscopy pulse rate at 7.5 p/s (55.4%), but this may not be standard practice in all Cath-Labs.

Performing a CTO was the main intervention leading to suspension of a procedure due to reaching the permitted radiation dose limit. Thereby, it is recommended that operators with experience in highly complex procedures must be aware of the importance of intensifying efforts to reduce radiation exposure for both the patient and the operator.8

Knowledge of the distribution of scattered radiation levels around a patient and the effective use of protective devices are crucial for team protection.12,21 Personal protective devices comprise aprons (or vest/skirt), thyroid protectors, eyewear and radiation protection gloves.22 All survey respondents used aprons and thyroid protectors. Aprons should be individually tailored, because if oversized, they normally provide insufficient protection to the exposed areas. The fitting of the protective apron is often more important to reduce effective dose than the lead equivalent. Aprons do not protect the neck, and if no thyroid protection is worn, the dose at which the unprotected thyroid is irradiated may be twofold that of the effective dose.12

The most important factor in protecting the head and the eyes is the proper use of ceiling shields. Lead glasses/visors are an important component of the eyewear protection, proved to reduce the lens exposed dose substantially.12 In one study, 45.0% of IC professionals had posterior subcapsular lens changes attributed to IR exposure with infrequently use of lead glasses (only 57% of IC).23 Considering the low rates of glasses/visors used in this study, across all professionals, alongside the scarcity of lens evaluation at occupational health, eye health may be neglected in the sample.

Protective gloves block 30.0–40.0% of the scattered radiation with some limitation of finger movement. Its use can be justified when the IC have to operate close to the irradiated area.22 In the current study, only 6.8% of main operators of the survey respondents used this type of protection.

Curtains attached to the patient table and properly placed ceiling suspended shields have been shown to dramatically reduce operator dose.22 This type of protection is common in Cath-Labs and was used by most survey respondents.

There are two main biological effects of radiation: deterministic or tissue effects, which cause immediate and predictable tissue lesion, like cataracts (in professionals) and skin burns (in patients); and stochastic effects, with long term carcinogenic and genetic alterations.3 Most operators seem to have an insight into the deleterious effects of IR, with high rates of concern about their own and their patients’ IR exposure.

Workers in category A should have at least one yearly occupational health appointment (including ophthalmologic/lens evaluation).13 Only 32.0% of the participants in the survey have been checked with this periodicity, despite the estimated real percentage of operators in category A being 64.9%.