Interventional radiology: lens and team skin

A 52-year-old interventional cardiologist has been performing catheterizations for 20 years, on average eight procedures a day. He goes to the ophthalmologist because he feels that the light from headlights at night has become glaring. The slit-lamp exam shows a small posterior subcapsular opacity in the left eye, and the right eye is almost normal. He does not have diabetes, does not use corticosteroids and has no history of eye trauma. He wears a lead apron and thyroid shield every day, but rarely wears the lead glasses because they weigh on his prescription glasses, and he almost never pulls the suspended shield close to the patient. The dosimeter sits in the apron pocket, under the lead. He asks the occupational physician whether the opacity is related to work, whether he can continue in the hemodynamics room and what needs to change. The scene is fictional and was written for teaching.

This text uses the case as a scenario for clinical reasoning for students and health professionals. The topic is occupational exposure to scattered radiation in interventional radiology and hemodynamics, with a focus on the lens and the skin of the team. The focus is what the occupational physician and the interventionalist themselves decide: recognize the pattern of the opacity, estimate the dose the eye received, correct the way it is measured, choose the protection that actually works and know the dose limit. It does not replace your service's radiation protection program or the medical physicist's assessment. If you play the case of the day on NEXO, you will recognize the challenge: deciding with clues that arrive in sequence.

Key points

• The ICRP currently considers a threshold of 0.5 Gy for effects on the lens.
• The occupational limit for the lens is 20 mSv per year averaged over 5 years, without exceeding 50 mSv in any single year.
• Posterior subcapsular opacity is the type most linked to radiation in the interventional team.
• The interventionalist's left eye usually receives more dose, because it is on the side of the tube and the patient.
• Lead glasses worn over prescription glasses reduce the dose well, and prescription lenses alone barely protect.
• A dosimeter under the apron does not measure the dose to the eye.

Why this is a reasoning scenario

The complaint in the scene is common, and cataract is one of the most frequent diseases after age 50. The clinical reasoning lies in not closing the diagnosis as age-related cataract before asking about work. The posterior subcapsular opacity in only one eye, the left eye, in a physician who spends hours beside an X-ray tube, is a strong clue to an occupational cause. The next question is how much the eye received, and the answer is almost never ready, because the dosimeter was in the wrong place.

Della Vecchia and colleagues reviewed 21 studies, and all of them recorded more cataract, especially posterior subcapsular, in health professionals exposed to ionizing radiation, with higher prevalence in the interventional cardiology team (Della Vecchia and colleagues, 2020). The same authors note that the data support a relationship between dose and the prevalence of opacities, especially posterior subcapsular ones (Della Vecchia and colleagues, 2020). They also recall that, over the last 30 years, interventional cardiology procedures have greatly increased the occupational exposure of the medical, nursing and technical team (Della Vecchia and colleagues, 2020).

The post on differential diagnosis helps keep the occupational cause among the hypotheses, and the post on interprofessional clinical reasoning shows why the medical physicist and the ophthalmologist join the same conversation.

What the scene teaches

The scene trains six habits. The first is to ask about occupational exposure when faced with a posterior subcapsular opacity. The second is to compare both eyes and remember that the left side usually receives a higher dose. The third is to check where the dosimeter is and whether there is a dosimeter for the eye. The fourth is to estimate the dose from the volume and the type of procedure. The fifth is to choose protective measures with a measured effect. The sixth is to extend the care to nursing and to the technologist, who stay close to the patient.

What is not at stake

The text does not address skin injury in patients undergoing long procedures guided by fluoroscopy, nor acute radiation syndrome, which were covered in other texts in this series. It also does not address the surgical technique of cataract surgery. The focus is the chronic exposure of the team, which adds up small doses over the years. The post about diagnostic pause helps to stop before calling the opacity age-related cataract.

The lens: threshold, limit and type of opacity

In April 2011, the ICRP reviewed the epidemiological evidence and concluded that some tissue effects with very late manifestation may have lower thresholds than previously thought (ICRP, 2011 statement). For the lens, the threshold in absorbed dose came to be considered 0.5 Gy (ICRP, 2011 statement). The same statement explains that these effects, formerly called deterministic, are now called tissue reactions, because they can be modified after exposure (ICRP, 2011 statement).

On that basis, the ICRP came to recommend, for occupational exposure, an equivalent dose limit to the lens of 20 mSv per year, averaged over defined periods of 5 years, without exceeding 50 mSv in any single year (ICRP, 2011 statement). The introductory text of the IAEA basic safety standard records that the previous limit was 150 mSv per year (IAEA, GSR Part 3). The reduction was large, and many services have not yet adjusted how they measure the dose to the eye.

The type of opacity

Lens opacities are classified by location as nuclear, cortical and posterior subcapsular (Della Vecchia et al., 2020). Alhasan and Aalam note that posterior subcapsular cataract accounts for about 10 percent of all cataracts, and almost half of them appear together with other types (Alhasan and Aalam, 2022). In these authors' meta-analysis, with 15 studies, exposed health professionals had a higher risk of posterior subcapsular cataract, of cataract and of any lens opacity than those not exposed (Alhasan and Aalam, 2022). In the analysis by group, nursing had the highest risk of posterior subcapsular cataract, with a hazard ratio of 4.00, followed by interventional cardiologists, with 3.85 (Alhasan and Aalam, 2022).

Lens density also separates the groups. Masumi et al. compared 150 people and found higher posterior lens density in the interventional radiology team than in operating room nursing staff who use a C-arm and than in the unexposed group (Masumi et al., 2026). There was no difference between operating room nursing and the unexposed group (Masumi et al., 2026). The finding suggests that intermittent exposure weighs less than the daily exposure of the interventional suite.

What the eye dose does not say on its own

Della Vecchia et al. note that the lowest dose capable of causing cataract and the relationship between dose and cataract in humans are not yet well established (Della Vecchia et al., 2020). Alhasan and Aalam note that studies show a higher risk of cataract even with exposure to low doses (Alhasan and Aalam, 2022). Therefore, the approach in the scene does not depend on proving the cause. It depends on reducing the future dose and following the eye with periodic examinations.

Where the team's dose comes from

The interventionalist barely receives the direct beam. Most of the dose comes from radiation scattered by the patient's body, which leaves in all directions and is more intense on the tube side. Hulthén and colleagues measured, with thermoluminescent dosimeters in phantoms, the relationship between the dose at the cardiologist's eye and the procedure's kerma-area product, in nine standard projections (Hulthén and colleagues, 2024). The highest coefficient was 5.47 µGy per Gy·cm² in the left lens (Hulthén and colleagues, 2024). The left lens had the highest value because it faces the patient and the tube in the usual working position.

Complex procedures and position in the room

The complexity of the procedure also matters. In the study by Vlastra and colleagues, staff interventional cardiologists performed 637 procedures and physicians in training performed 129, from January to May 2017 (Vlastra and colleagues, 2019). The more complex procedures performed by staff interventionalists used 74 percent more radiation than those of physicians in training (Vlastra and colleagues, 2019). As a result, staff interventionalists had 50 percent more actual exposure (Vlastra and colleagues, 2019).

In catheter-based aortic valve implantation, Zanon and colleagues recorded operator lens doses of about 30 to 110 µSv per procedure (Zanon and colleagues, 2026). Doses were higher in transapical or transaortic access and in the team that stays near the patient, such as anesthesiologists and circulating staff (Zanon and colleagues, 2026). The authors estimate that accumulated exposure may approach the limits after about 150 to 300 procedures, depending on role, access and protection used (Zanon and colleagues, 2026).

The physician's own head

One detail changes the measurement. Ohno and colleagues showed in phantoms that radiation backscattered by the physician's own head accounted for 17.3 to 22.3 percent of the lens dose, increasing with tube voltage (Ohno and colleagues, 2024). They conclude that the dosimeter must be in close contact with the skin to measure this portion well (Ohno and colleagues, 2024). In the scene, the dosimeter in the pocket, under the apron, measures none of this.

Protection: what reduces the eye dose

Eye protection combines distance, shielding and imaging technique. No single measure solves it, and the choice depends on what has a measured effect. The IAEA basic standard uses the quantity Hp(3) to monitor lens exposure (IAEA, GSR Part 3). This means a dedicated dosimeter, near the eye, and not the body dosimeter.

Lead glasses and prescription glasses

The physician's problem in the scene is common: he wears prescription glasses and finds it uncomfortable to put lead glasses over them. Shindo and colleagues tested in phantoms lead glasses of the type worn over prescription glasses (Shindo and colleagues, 2025). Against radiation coming from below and from the left, as in clinical practice, the mean shielding rate was 0.72 to 0.74 in the left eye and 0.74 to 0.80 in the right eye (Shindo and colleagues, 2025). The plastic lenses of prescription glasses alone reduced the dose by less than 9 percent with 80 and 120 kV X-rays (Shindo and colleagues, 2025). The practical conclusion is that prescription glasses do not replace lead glasses.

Shields and imaging technique

In Zanon and colleagues' review of aortic valve implantation, additional shielding and lead-free drapes reduced the normalized eye dose by about 25 to 40 percent (Zanon and colleagues, 2026). A disposable protective drape reduced the dose at the operator's eye level from 24.3 to 14.8 µSv per procedure (Zanon and colleagues, 2026). The authors recommend combining routine eye protection and eye-level dosimetry with imaging adjustments: low pulse rate fluoroscopy, fewer cine and digital subtraction acquisitions and narrow collimation (Zanon and colleagues, 2026). They also highlight that team position and beam angulation strongly influence the dose (Zanon and colleagues, 2026).

The table summarizes the measures and what is known about the effect.

Measure	Described effect	Source
Lead glasses over prescription glasses	Shielding rate from 0.72 to 0.80	Shindo and colleagues, 2025
Prescription lenses without lead	Reduction of less than 9 percent	Shindo and colleagues, 2025
Additional shielding and lead-free drapes	Reduction of about 25 to 40 percent	Zanon and colleagues, 2026
Disposable protective drape	From 24.3 to 14.8 µSv per procedure	Zanon and colleagues, 2026
Dosimeter close to the skin of the face	Measures backscatter of 17 to 22 percent	Ohno and colleagues, 2024

The order of actions

The list below organizes the changes the physician in the room can make starting tomorrow, each linked to a source:

• Use lead glasses of the type that fits over prescription glasses in all {SHI} procedures.
• Pull the suspended shield close to the patient and use the additional table shielding {ZAN}.
• Reduce the pulse rate, limit cine and collimate the beam {ZAN}.
• Request a lens dosimeter, in Hp(3), near the left eye {GSR}.
• Review with the medical physicist the annual volume and the estimated dose per procedure {HUL}.

Skin and hands of the team

The eye is not the only organ at risk. The IAEA basic safety standards set for the worker a limit of equivalent dose to the extremities, hands and feet, or to the skin, of 500 mSv per year (IAEA, GSR Part 3). The skin limit applies to the average dose over 1 cm² of the most irradiated area (IAEA, GSR Part 3). The operator's hands are often near the beam, and sometimes inside it.

Kumagai and colleagues followed orthopedic surgeons at a university hospital in Japan in 2019 and 2024 (Kumagai and colleagues, 2026). They compared the weekly fluoroscopy time reported by the physicians and the skin findings on the hands assessed by a dermatologist (Kumagai and colleagues, 2026). Between 2020 and 2023, educational campaigns reinforced the principle of keeping the dose as low as reasonably possible and the use of personal protective equipment (Kumagai and colleagues, 2026). The proportion of surgeons attentive to radiation rose from 5.8 to 70.9 percent (Kumagai and colleagues, 2026). The prevalence of radiation skin injury fell from 34.9 to 25.6 percent (Kumagai and colleagues, 2026). The authors conclude that, during the period of repeated education, the surgeons improved their safety attitude, reduced the reported fluoroscopy time and had better skin findings (Kumagai and colleagues, 2026).

The study is of orthopedic surgeons, not cardiologists, but the lesson applies to the cath lab. Repeated education changes behavior, and behavior changes the dose. In the room, the same consultation that found the opacity is the moment to examine the hands.

Pregnancy on the team

The IAEA basic safety standards say that a worker's notification of suspected pregnancy or breastfeeding should not be grounds for removing her from work (IAEA, GSR Part 3). The employer must adapt working conditions so that the embryo, the fetus or the breastfed baby have the same level of protection required for the public (IAEA, GSR Part 3). The standard also makes clear that notification cannot be imposed, but that every worker needs to understand the importance of doing it (IAEA, GSR Part 3). For the occupational physician, this means talking about the topic with the whole team, and not only with those who are already pregnant.

Risks and reasoning errors

The most common errors in this scenario are of reasoning and of habit. The list summarizes the main ones:

• Calling the opacity age-related cataract without asking about the work {DVE}.
• Relying on the body dosimeter under the apron to estimate the eye dose {OHN}.
• Thinking that prescription glasses protect the eye {SHI}.
• Forgetting nursing and anesthesia, who stay near the patient and also receive dose {ZAN}.
• Not adjusting the imaging technique in the more complex procedures, which use more radiation {VLA}.
• Examining only the eyes and forgetting the skin of the hands {KUM}.

The question about removal from work

The doctor in the scene asks whether he can stay in the hemodynamics room. The answer depends on the dose he receives, not only on the finding in his eye. The lens limit is 20 mSv per year averaged over 5 years and 50 mSv in a single year (IAEA, GSR Part 3). If correct dosimetry shows that he stays below this limit with the new protection, he can continue. If it shows that he is above it, the service needs to change the routine, and removal from the role is one of the options. The decision is shared among the occupational physician, the medical physicist and the ophthalmologist.

The scale of the problem

Hulthén and colleagues note that attention in recent years has focused on the new ICRP limit for the lens (Hulthén and colleagues, 2024). They also record publications on other operator risks, such as lens opacity and brain tumors (Hulthén and colleagues, 2024). Vlastra and colleagues cite cataract and left-sided brain tumors among the radiation-related diseases in interventionalists (Vlastra and colleagues, 2019). The 2011 ICRP statement also warns that the threshold for circulatory disease may be only 0.5 Gy in the heart or brain, and that patients undergoing complex interventional procedures may reach this dose (ICRP, 2011 statement).

Regulatory situation: ICRP and IAEA

The ICRP statement on tissue reactions was approved on April 21, 2011 (ICRP, 2011 statement). It recommends that optimization of protection be applied in all situations and categories of exposure (ICRP, 2011 statement). It also stresses that protection should be optimized not only for the whole body but also for specific tissues, especially the lens, the heart and the cerebrovascular system (ICRP, 2011 statement).

The IAEA basic safety standard, GSR Part 3, adopted the new limit (IAEA, GSR Part 3). The presentation text records that the chair of the Commission on Safety Standards approved the new lens limit on July 12, 2011, after consultation with Member States (IAEA, GSR Part 3). For workers over 18 years of age, the limits are 20 mSv per year of effective dose averaged over five years, 20 mSv per year for the lens averaged over five years, both without exceeding 50 mSv in a single year, and 500 mSv per year for the extremities or the skin (IAEA, GSR Part 3). For apprentices and students aged 16 to 18, the lens limit is 20 mSv in a year (IAEA, GSR Part 3). For the public, the lens limit is 15 mSv in a year (IAEA, GSR Part 3).

Limits that apply in each country

The IAEA standard is an international reference, and each country adopts it in its own regulations. Shindo and colleagues note that the ICRP reduced the occupational lens limit to 20 mSv per year (Shindo and colleagues, 2025). Professionals should check with their radiation protection service which limit is in force in their country and how eye dose is measured.

How NEXO helps train this reasoning

NEXO publishes one fictional clinical case per day, with up to six progressive clues. You can attempt the diagnosis at each clue, searching for the ICD-10 code, and you receive proximity feedback at five levels. The format trains the same skill as this scene: putting together data that arrive gradually, such as the type of opacity, the side of the eye, the workload and the dosimeter position, and deciding without closing too early. The post on case-based learning explains why this format works, and the post on clinical decision-making helps choose the order of measures.

Three exercises with cases

The first exercise is to redo the scene with a 45-year-old circulating nurse with the same finding and discuss where her dose came from. The second is to redo the scene with a doctor who works on the patient's right side and predict which eye would receive more dose. The third is to redo the scene with a female doctor in training who has just discovered she is pregnant and decide what the service should change.

Teachers and content creators can build their own cases in the space for Creators. The exercise works well in cardiology, radiology and orthopedics residencies and in occupational health training.

Frequently asked questions

What is the occupational limit for the lens?

20 mSv per year averaged over 5 years, without exceeding 50 mSv in a single year (IAEA, GSR Part 3).

What is the threshold for lens effects?

The ICRP currently considers 0.5 Gy of absorbed dose (ICRP, 2011 statement).

Do prescription glasses protect?

Barely. Plastic lenses reduced the dose by less than 9 percent in phantoms (Shindo et al., 2025).

Why the left eye?

Because, in the usual position, it faces the patient and the tube and receives the highest dose coefficient (Hulthén et al., 2024).

Which type of opacity is most linked to radiation?

Posterior subcapsular (Della Vecchia et al., 2020).

Final checklist

• I asked about occupational exposure in the presence of opacity.
• I compared both eyes and noted the more affected side.
• I checked where the dosimeter is and requested a lens dosimeter.
• I estimated the dose from volume and procedure type with the medical physicist.
• I recommended lead glasses over prescription glasses.
• I reviewed shields, protective fields, pulse rate and collimation.
• I examined the skin of the hands.
• I extended the conversation to nursing, anesthesia and technologists.

Want to practice your reasoning with progressive clues? Play the case of the day.

References

1. Alhasan AS, Aalam WA. Eye lens opacities and cataracts among physicians and healthcare workers occupationally exposed to radiation: A systematic review and meta-analysis. Saudi Med J. 2022. PMID 35830987.
2. Della Vecchia E, Modenese A, Loney T, et al. Risk of cataract in health care workers exposed to ionizing radiation: a systematic review. Med Lav. 2020. PMID 32869764.
3. Hulthén M, Tsapaki V, Karambatsakidou A. Estimating brain and eye lens dose for the cardiologist in interventional cardiology-are the dose levels of concern? Br J Radiol. 2024. PMID 38711194.
4. International Atomic Energy Agency. Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards. General Safety Requirements Part 3. Vienna: IAEA, 2014. Official source.
5. International Commission on Radiological Protection. Statement on Tissue Reactions. ICRP ref 4825-3093-1464. April 2011. Official source.
6. Kumagai G, Rokunohe D, Sasaki E, et al. Occupational Ionizing Radiation-Induced Skin Injury Among Orthopedic Surgeons: A 5-Year Longitudinal Cohort Study. JB JS Open Access. 2026. PMID 41550579.
7. Masumi Z, Bagheri M, Feizi R, Khodamoradi E. Occupational radiation exposure and crystalline lens density in perioperative nurses: a short communication. BMC Nurs. 2026. PMID 42157187.
8. Ohno S, Konta S, Shindo R, et al. Effect of backscatter radiation on the occupational eye-lens dose. J Radiat Res. 2024. PMID 38818635.
9. Shindo R, Yamamoto K, Ohno S, et al. Evaluation of radiation protection by lead glasses for interventional radiology physicians wearing prescription glasses: considering dose reduction by prescription glasses excluding lead. J Radiat Res. 2025. PMID 40795890.
10. Vlastra W, Claessen BE, Beijk MA, et al. Cardiology fellows-in-training are exposed to relatively high levels of radiation in the cath lab compared with staff interventional cardiologists-insights from the RECAP trial. Neth Heart J. 2019. PMID 30843153.
11. Zanon C, Fiocco A, Tarzia V, Quaia E. Eye Lens Radiation Exposure During TAVI: Current Evidence and Imaging-Based Strategies for Dose Reduction. Tomography. 2026. PMID 41893831.