Radiation skin injury: iridium source in the pocket

A 34-year-old industrial radiography assistant works at a piping construction site. At the end of the shift, he finds a small, shiny metal piece on the ground, looking like a piece of cable, and puts it in the front pocket of his pants to return to his boss the next day. He forgets the piece there for about five hours, sitting in the pickup truck cab and then at home. At night, he feels a burning sensation in his right thigh. The next day, a red patch with a small blister appears, and the emergency physician thinks of an insect bite. Two days later, the company announces that an iridium-192 source has disappeared from the gamma radiography camera. The scene is fictional and was written for teaching.

This text uses the case as a setting for clinical reasoning for students and health professionals. The topic is radiation skin injury, which the International Atomic Energy Agency manual calls a local radiation injury. The focus is what the physician decides when a burn has no heat or chemical product in the history: suspect the source, call radiation protection, separate local injury from whole-body exposure, estimate the dose and plan the wound over weeks. It does not replace your service's protocol or contact with the radiation protection authority in your country. If you play the case of the day on NEXO, you will recognize the challenge: deciding with clues that arrive in sequence.

Key points

• A burn with no history of heat or chemical product is a strong clue to local radiation injury.
• The injury evolves in waves over weeks, and the appearance on the first day underestimates the damage.
• By IAEA thresholds, erythema in the manifestation phase appears from about 3 Gy and necrosis from about 25 Gy.
• Serial blood counts with lymphocyte count help show whether there was also whole-body exposure.
• A biopsy in the irradiated area can open an ulcer and should be avoided.
• In deep injuries, current management is early surgery guided by a dose map, and follow-up lasts a lifetime.

Why this is a reasoning setting

Industrial radiography uses powerful gamma sources to examine welds and metal parts. When a source comes loose from the camera and no one notices, it can end up in someone's pocket. That is what happened in Yanango, Peru, in February 1999. A welder picked up an unshielded iridium-192 source with his right hand and put it in his back pants pocket (IAEA report on Yanango). The source had an activity of 1.37 TBq on the day of the accident (IAEA report on Yanango). He kept working for hours and felt pain in the back of his right thigh around 9 pm (IAEA report on Yanango). At home, his wife saw a red area on the skin, and a local physician said it was an insect bite and recommended a warm compress (IAEA report on Yanango). The injury evolved over months and ended in amputation of the leg (IAEA report on Yanango).

In Iran, in July 1996, a worker at a plant in Gilan found a shiny metal object the size of a pencil in a ditch and put it in his chest pocket (IAEA report on Gilan). It was an unshielded iridium-192 source of 185 GBq (IAEA report on Gilan). He had nausea, fatigue and burning in the chest, and the injury evolved to moist desquamation over an area of 30 cm by 15 cm (IAEA report on Gilan). The blood count and other indicators also showed whole-body exposure compatible with about 4.5 Gy (IAEA report on Gilan).

The two reports show the same pattern. The injury looks trivial at first, the exposure history does not appear on its own, and the diagnosis depends on someone linking the skin to the lost source. The post on diagnostic uncertainty helps sustain doubt in the first hours, and the post on differential diagnosis shows how to keep hypotheses open while new clues arrive.

What the scene teaches

The scene trains six habits. The first is to ask about work and found objects when a skin lesion has no clear cause. The second is to call radiation protection and the company as soon as the source enters the hypothesis. The third is to order a blood count with lymphocytes to look for whole-body exposure. The fourth is to photograph the lesion in series, with date and time. The fifth is to request dose reconstruction before deciding on surgery. The sixth is to plan lifelong follow-up.

What is not at stake

The text does not cover in detail acute radiation syndrome, which was the topic of the first text in this series, nor internal contamination by cesium, which was the topic of the second. It also does not cover skin lesions in patients undergoing fluoroscopy-guided procedures nor chronic occupational exposure of the hemodynamics team, which are left for another text in the series. The post about diagnostic pause recalls that closing as an insect bite was exactly the error in the reports.

Phases and dose thresholds in the skin

A lesion that evolves in waves

Local radiation injury is a deterministic effect, also called a tissue effect, and severity follows dose (IAEA, medical management of radiation injuries, 2020). Its main feature is being a dynamic process, with inflammatory waves that develop over time, sometimes unpredictably (IAEA, medical management of radiation injuries, 2020). The first response is a primary erythema, which may appear a few hours after high exposure due to capillary dilation (IAEA, medical management of radiation injuries, 2020). The earlier this erythema appears, the higher the dose absorbed by the skin (IAEA, medical management of radiation injuries, 2020). Primary erythema may go unnoticed, especially in dark skin (IAEA, medical management of radiation injuries, 2020).

Then comes a latent period. The primary erythema fades and is followed by secondary erythema and dry desquamation between about one and five weeks, and the shorter this interval, the higher the dose (IAEA, medical management of radiation injuries, 2020). If the dose is sufficient, the manifestation phase can reach moist desquamation, blisters, ulcers and deep necrosis, the latter for doses above 25 Gy (IAEA, medical management of radiation injuries, 2020). Late erythema may appear between 6 and 18 months after exposure in high-dose lesions (IAEA, medical management of radiation injuries, 2020). REMM describes the same sequence: prodromal phase with erythema, edema and itching, latent phase and manifestation phase (REMM, cutaneous radiation syndrome).

Approximate thresholds

The 2020 IAEA manual provides approximate thresholds for acute exposure and notes that they change with the size of the irradiated field, radiation quality and each person's sensitivity (IAEA, medical management of radiation injuries, 2020). REMM does not publish its own values and recalls that the literature gives wide threshold ranges (REMM, cutaneous radiation syndrome). The table below reproduces the manual's values.

Manifestation	Dose threshold	Approximate onset	Source
Erythema of the manifestation phase	3 Gy	14 to 21 days	(IAEA, medical management of radiation injuries, 2020)
Temporary hair loss	3 Gy	14 to 18 days	(IAEA, medical management of radiation injuries, 2020)
Permanent hair loss	7 Gy	25 to 30 days	(IAEA, medical management of radiation injuries, 2020)
Dry desquamation	10 Gy	20 to 28 days	(IAEA, medical management of radiation injuries, 2020)
Moist desquamation	15 Gy	15 to 25 days	(IAEA, medical management of radiation injuries, 2020)
Necrosis	25 Gy	More than 21 days	(IAEA, medical management of radiation injuries, 2020)

Hair follicles are very sensitive. A dose of 2 Gy can cause follicle dysplasia, 3 Gy can cause temporary hair loss between the second and fourth week, and above 7 Gy the loss is permanent (IAEA, medical management of radiation injuries, 2020). Therefore, the area where hair is still firm helps estimate the dose later. In Yanango, the skin dose 14 cm from the center of the lesion, where hair remained firm, was estimated at about 2 Gy (IAEA report on Yanango).

Why the source in the pocket is so serious

Dose falls very fast with distance from a point source. In the Yanango case, the reconstruction considered the source 3 mm from the skin with the man seated and 7 mm standing, because of the loose trousers (IAEA report on Yanango). The estimated dose at the edge of the lesion was about 25 Gy, and the 100 Gy curve on the surface lay between 2 and 3 cm from the center of the lesion (IAEA report on Yanango). The femur received from 15 Gy at entry to 5 Gy at exit, the femoral artery from 10 to 15 Gy and the sciatic nerve, closer to the source, from 25 to 30 Gy (IAEA report on Yanango). The same man received very little dose in distant parts of the body and a destructive dose in a few centimeters of thigh. The review by Iddins and colleagues recalls that rhabdomyolysis and osteonecrosis can be expected when the dose to muscle and bone exceeds about 40 Gy (Iddins and colleagues, 2022).

A single source can cause lesions in more than one place. In Gilan, the worker took the source out of his pocket to look at it and put it back several times (IAEA report on Gilan). Besides the chest, erythema appeared in the crook of the elbow and a tense blister on the palm of the left hand (IAEA report on Gilan). Every place that touched the source is a potential lesion, and the examination must look for all of them.

Diagnosis: history, tests and dose reconstruction

The differential before the source appears

Before anyone mentions a source, the assistant's lesion can look like many things. The IAEA records that acute radiation injuries have been mistaken for insect bites, skin allergy, thermal or chemical burns and even pemphigus foliaceus (IAEA, medical management of radiation injuries, 2020). The clinical findings are not specific, and without a clear history of exposure and without active suspicion from the doctor the diagnosis tends to be wrong (IAEA, medical management of radiation injuries, 2020). The manual sums up the main clue like this: a burn with no history of heat or of a chemical product is a strong sign of a local radiation injury (IAEA, medical management of radiation injuries, 2020). The question that changes the case is simple: what did you pick up or carry near that area in the last few days?

Local injury and whole body

The skin lesion can appear without acute radiation syndrome (REMM, cutaneous radiation syndrome). But the same source that burns the thigh also irradiates the rest of the body, at a lower dose. In every local injury, the IAEA recommends an initial blood count, another after 6 to 8 hours and then one every 24 hours, with attention to lymphocyte kinetics, to assess whole-body exposure (IAEA, medical management of radiation injuries, 2020). In Gilan, the fall in lymphocytes and the aplastic marrow on day 20 showed significant whole-body exposure beyond the chest lesion (IAEA report on Gilan). In Yanango, cytogenetic dosimetry estimated about 1.2 Gy for the whole body (IAEA report on Yanango). The 2011 consensus on the acute syndrome recalls that the hematopoietic, cutaneous, gastrointestinal and neurovascular syndromes can appear alone or combined (Dainiak and colleagues, 2011).

Tests that help

In severe cases or cases that may become severe, the assessment includes several resources, according to clinical judgment and availability (IAEA, medical management of radiation injuries, 2020):

• Serial, standardized color photography, with date and time noted, to follow the evolution.
• High-resolution ultrasound to see the damage beneath the skin.
• CT and MRI to measure the depth of the lesion.
• Assessment of blood flow by scintigraphy or Doppler.
• Thermography, which shows the distribution of heat on the skin and helps measure the extent of the lesion.
• Early physical dose reconstruction by Monte Carlo simulation.

The review by Iddins and colleagues describes the combined use of ultrasound and thermography in patients seen at the United States reference center and concludes that they give additional diagnostic information for management (Iddins and colleagues, 2022). In necrosis, the skin temperature tends to be much lower (IAEA, medical management of radiation injuries, 2020).

Biopsy: better not

A biopsy in an area of local radiation injury is dangerous, because it can open an ulcer in tissues already weakened by radiation (IAEA, medical management of radiation injuries, 2020). REMM lists biopsy among the assessment options (REMM, cutaneous radiation syndrome), but the IAEA manual is explicit about the risk. In practice, biopsy only comes in when the diagnostic doubt changes management and after a conversation with the reference team.

Dose reconstruction

When high local exposure is suspected, it is essential to reconstruct the dose at different depths of the skin and other structures (IAEA, medical management of radiation injuries, 2020). A good-quality tomography of the exposed area generates a numerical model of the patient, and the exposure is repeated on the computer with the same type of source, the same distance and the same time (IAEA, medical management of radiation injuries, 2020). The result is a dose map that guides prognosis and the best treatment strategy (IAEA, medical management of radiation injuries, 2020). The review by Lima and colleagues describes the physical methods, such as electron paramagnetic resonance, thermoluminescence and optically stimulated luminescence (Lima and colleagues, 2015). Paramagnetic resonance in tooth enamel is the most advanced physical method for estimating dose retrospectively, and other materials, such as nails, hair, clothing and plastic, can be used (Lima and colleagues, 2015). Detection limits vary widely, from about 100 mGy in enamel to 10 Gy in cotton (Lima and colleagues, 2015).

Reconstruction depends on knowing where the source was and for how long. That is why the interview with the patient and with the company is part of the examination. The post about simulation of care helps train the timeline: the time the piece was picked up, where it was stored, when it was removed, who else was nearby.

Management: from the wound to dosimetry-guided surgery

The first care

In external exposure, the person receives radiation from a source outside the body and does not retain radioactive material on the skin or clothing (Kazzi and colleagues, 2015). An intact sealed iridium-192 source fits this case: after it has been removed and stored by the radiation protection team, the patient can be treated like any other. The 2011 consensus recommends assessing external contamination with a detector on the skin surface when there is doubt (Dainiak and colleagues, 2011). In the scene assistant, the detector measurement confirms that there is no contamination and clears the way for routine care.

In Peru, the welder was admitted about 20 hours after exposure and received intravenous fluids, antibiotics, intravenous corticosteroids and analgesics (IAEA report on Yanango). The lesion already had a blister on the second day (IAEA report on Yanango). This short time to blistering was a sign of high dose, by the logic that the earlier, the worse (IAEA, medical management of radiation injuries, 2020).

Treatment by phase

There are no controlled trials to guide treatment, and management follows standard care for non-radiation skin injuries (Dainiak and colleagues, 2011). REMM describes individualized wound treatment, with tetanus vaccine, fluids, control of pain and itching, topical corticosteroids, antimicrobials, growth factors, pentoxifylline, anticoagulation, debridement, grafting and, in extreme cases, amputation (REMM, cutaneous radiation syndrome). The 2011 consensus mentions silver sulfadiazine cream with non-adherent dressings in the moist desquamation phase (Dainiak and colleagues, 2011). Ulcers, localized necrosis and severe pain that does not subside are best treated by surgical excision and grafting (Dainiak and colleagues, 2011).

Each phase calls for different care. In erythema and dry desquamation, the care is for the skin, with protection against trauma and heat and relief of itching, and lotions or sprays with hydrocortisone can relieve severe erythema with edema (IAEA and WHO, 1998 manual) (REMM, cutaneous radiation syndrome). In moist desquamation, daily dressings come in, bathing the skin in antiseptic solution and topical antibiotic if there is infection (IAEA and WHO, 1998 manual) (IAEA, medical management of radiation injuries, 2020). In the chronic phase, pentoxifylline can improve microcirculation, with attention to fluid balance to avoid hemoconcentration (IAEA, medical management of radiation injuries, 2020). In deep ulcer and necrosis, surgery is the treatment, preferably guided by the dose map (IAEA, medical management of radiation injuries, 2020).

The 2018 review of mass casualty incidents records strong recommendations for topical corticosteroid, antihistamine and antibiotic in ulcers, blisters and radiation burns, and for excision and grafting of ulcers and localized necrosis (Dainiak, 2018). The same review recommends not using systemic corticosteroid for radiation skin injury without another specific indication (Dainiak, 2018).

Pain as a sign

Pain from deep ulcer and necrosis is a central symptom of the injury as it evolves, and controlling it is very difficult (IAEA, medical management of radiation injuries, 2020). Pain severity also indicates the risk of long-term recurrence (IAEA, medical management of radiation injuries, 2020). The 2011 consensus notes that chronic pain from nerve bundle compression is a frequent complication of radiation ulcers (Dainiak and colleagues, 2011). In Gilan, grafting the chest injury greatly improved the patient's mood and pain (IAEA report on Gilan).

Wait or operate

In the past, management was conservative: wait, see and then intervene (IAEA, medical management of radiation injuries, 2020). This approach had poor results in severe injuries, with serious consequences for quality of life (IAEA, medical management of radiation injuries, 2020). The problem is that surgery in an area of deep necrosis triggers new waves of inflammation (IAEA, medical management of radiation injuries, 2020). Since 2006, an approach called dosimetry-guided surgery has combined local dose estimation with early surgery (IAEA, medical management of radiation injuries, 2020). The dose map shows the areas above 25 Gy, where necrosis is likely, and the surgeon performs preventive excision of these areas (IAEA, medical management of radiation injuries, 2020). The IAEA indicates this surgery early when deep ulcer or necrosis is expected, for example when erythema, blisters and edema appear shortly after irradiation (IAEA, medical management of radiation injuries, 2020).

Yanango helped change this view. After that accident, in which the patient needed amputation, researchers began studying mesenchymal stem cells from bone marrow to treat radiation skin injuries (Iddins and colleagues, 2022). In dosimetry-guided surgery, the cells are injected during the operation into several parts of the operated area and again in sessions afterward (IAEA, medical management of radiation injuries, 2020). The IAEA cites the use of these cells in late radiation ulcers with an area smaller than 20 cm2 (IAEA, medical management of radiation injuries, 2020). The review by Iddins and colleagues describes promising results in animal models, humanitarian use and clinical trials with cells from the patient's own marrow and fat (Iddins and colleagues, 2022).

Other options and rehabilitation

Hyperbaric oxygen therapy has been used in some cases with apparently good results, but the lack of controlled trials does not allow it to be clearly indicated (IAEA, medical management of radiation injuries, 2020). Specialized physical therapy plays a central role in recovery after surgery, to maintain joint function and avoid excessive scarring (IAEA, medical management of radiation injuries, 2020). The post on interprofessional clinical reasoning helps to think about the team this patient needs: plastic surgery, burns center, pain, medical physics, physical therapy and mental health.

Lifelong follow-up

Anyone who had a serious injury needs close follow-up (IAEA, medical management of radiation injuries, 2020). The IAEA advises avoiding temperature extremes, irritating products and trauma in the area, identifying recurrences and surgical complications, and paying attention to smoking, diabetes and arterial diseases, which worsen ischemia (IAEA, medical management of radiation injuries, 2020). In principle, follow-up is for life (IAEA, medical management of radiation injuries, 2020). Late effects include telangiectasia, atrophy, fibrosis and non-melanoma skin cancer, such as basal cell and squamous cell carcinoma (IAEA, medical management of radiation injuries, 2020). REMM notes that cancer can appear years later (REMM, cutaneous radiation syndrome).

Risks and reasoning errors

Closing too early

The most repeated error in the reports is giving the injury a common name on the first day. In Yanango, the insect bite hypothesis led to a warm compress and delayed recognition of the source (IAEA report on Yanango). The IAEA lists several other misdiagnoses already recorded (IAEA, medical management of radiation injuries, 2020). The antidote is the question about exposure whenever a burn has no heat or chemical product.

Judging by the first day's appearance

The injury evolves in waves, and the primary erythema may disappear (IAEA, medical management of radiation injuries, 2020). A patient who seems better on the third day may be only in the latent period. In Gilan, the chest injury kept worsening for 16 days until it reached moist desquamation and early necrosis (IAEA report on Gilan). The plan must provide for reassessment over weeks, not hours.

Forgetting the whole body

A striking local injury can hide a whole-body exposure. Without serial blood counts, the drop in lymphocytes goes unnoticed (IAEA, medical management of radiation injuries, 2020). In Gilan, the worker had severe bone marrow depression in addition to the chest injury (IAEA report on Gilan).

Forgetting the other exposed people

In Yanango, the welder's wife sat for a few minutes on the trousers with the source while breastfeeding her 18-month-old son, and two other children stayed 2 or 3 meters from the source for about two hours (IAEA report on Yanango). Later, she had moist desquamation and an ulcer in the lumbar region (IAEA report on Yanango). Fifteen people traveled in the same minibus as the welder (IAEA report on Yanango). The history of who was nearby is part of the care.

Trusting a single dose estimate

In the Peruvian case, the doses estimated in Peru and in France were quite different (IAEA report on Yanango). The report comments that this shows how much the dose estimate by physicists depends on the assumptions made (IAEA report on Yanango). The reconstructed dose guides, but it must be read together with the clinical picture and revised when new data appear. The post on clinical decision-making helps weigh an uncertain number against what the wound shows.

Regulatory situation: FDA and IAEA

Medicines and devices in the United States

The review by Iddins and colleagues records that there are no medicines specifically approved by the FDA, the United States medicines agency, to treat cutaneous or local radiation injury (Iddins and colleagues, 2022). The same review describes research funded by the American government, such as a human keratin cream studied in radiation skin injuries in pigs and in people (Iddins and colleagues, 2022). On October 26, 2022, the FDA cleared via the 510(k) pathway a silver-coated nylon dressing for use for up to 7 days in radiation dermatitis and in cutaneous radiation injury up to the dry desquamation stage (FDA, 510(k) K221218). Clearance via 510(k) means that the agency considered the device substantially equivalent to others already on the market (FDA, 510(k) K221218). REMM cites this dressing among the management options (REMM, cutaneous radiation syndrome).

What the IAEA publishes

The IAEA does not approve medicines, but it publishes accident reports and management manuals. The Yanango report was published in 2000 and the Gilan report in 2002 (IAEA report on Yanango) (IAEA report on Gilan). The 2020 manual on medical management of radiation injuries replaces the 1998 manual, published with the World Health Organization (IAEA and WHO, 1998 manual), and sets out the thresholds and the management cited in this text (IAEA, medical management of radiation injuries, 2020). The same publication lists the situations in which the local injury has already occurred: radiotherapy and interventional radiology accidents, industrial radiography, irradiators, nuclear power plants and criminal acts (IAEA, medical management of radiation injuries, 2020).

Use of cells and surgery

The mesenchymal stem cells cited in this text were used in accidents, humanitarian use and clinical trials (Iddins and colleagues, 2022). The IAEA describes their use within dosimetry-guided surgery (IAEA, medical management of radiation injuries, 2020). Outside these contexts, use depends on the rules of each country and of the reference center.

How NEXO helps train this reasoning

In NEXO, each case arrives in progressive clues, as in real life. The cutaneous radiation injury is a good example of a diagnosis that depends on a history question asked at the right moment. The exercises below were designed to train this.

Three exercises with cases

• Write five diagnoses for a blister on the thigh of a worker with no history of burns and say which question would separate each one from radiation injury.
• Build a 30-day timeline for the scene, with the expected phases, the blood count schedule and the dates of the photos.
• Given a dose map with an area above 25 Gy, explain to the patient why early surgery may be better than waiting.

The post on case-based learning explains why this type of training makes reasoning stick better. If you write cases, the page for Creators shows how to collaborate.

Frequently asked questions

Is a person with an injury from a sealed source radioactive?

No, if the source is intact and has already been removed. External exposure does not leave radioactive material on the skin (Kazzi and colleagues, 2015), and the detector confirms it (Dainiak and colleagues, 2011).

At what dose does necrosis appear?

According to the IAEA manual, from about 25 Gy, with onset after 21 days (IAEA, medical management of radiation injuries, 2020).

Can I do a biopsy to confirm?

Better to avoid it. A biopsy can open an ulcer in the irradiated tissue (IAEA, medical management of radiation injuries, 2020).

Why order a blood count for a skin injury?

Because the same source may have irradiated the whole body. The IAEA recommends serial blood counts with attention to lymphocytes (IAEA, medical management of radiation injuries, 2020).

Is there an approved medicine for this injury?

The 2022 review records that there is no FDA-approved medicine for this purpose (Iddins and colleagues, 2022). A silver dressing was cleared as a device in 2022 (FDA, 510(k) K221218).

Final checklist

• I asked about work, found objects and what was in the pocket.
• I called radiation protection and the company responsible for the source.
• I confirmed with a detector that there was no contamination.
• I ordered an initial blood count, at 6 to 8 hours and then daily.
• I photographed the injury in series, with date and time.
• I avoided biopsy in the irradiated area.
• I requested dose reconstruction and discussed dosimetry-guided surgery.
• I asked about other exposed people and planned lifelong follow-up.

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

References

1. Dainiak N. Medical management of acute radiation syndrome and associated infections in a high-casualty incident. J Radiat Res. 2018. PMID 29509947.
2. Dainiak N, Gent RN, Carr Z, et al. Literature review and global consensus on management of acute radiation syndrome affecting nonhematopoietic organ systems. Disaster Med Public Health Prep. 2011. PMID 21986999.
3. Food and Drug Administration. 510(k) K221218, Silverlon Wound Contact, Burn Contact Dressings. Letter of 10/26/2022. Official source.
4. Iddins CJ, DiCarlo AL, Ervin MD, et al. Cutaneous and local radiation injuries. J Radiol Prot. 2022. PMID 34488201.
5. International Atomic Energy Agency. Medical Management of Radiation Injuries. Safety Reports Series No. 101. Vienna: IAEA, 2020. Official source.
6. International Atomic Energy Agency. The Radiological Accident in Gilan. Vienna: IAEA, 2002. Official source.
7. International Atomic Energy Agency. The Radiological Accident in Yanango. Vienna: IAEA, 2000. Official source.
8. International Atomic Energy Agency, World Health Organization. Diagnosis and Treatment of Radiation Injuries. Safety Reports Series No. 2. Vienna: IAEA, 1998. Official source.
9. Kazzi Z, Buzzell J, Bertelli L, et al. Emergency department management of patients internally contaminated with radioactive material. Emerg Med Clin North Am. 2015. PMID 25455668.
10. Lima CM, Lima AR, Degenhardt ÄL, et al. Reconstructive dosimetry for cutaneous radiation syndrome. Braz J Med Biol Res. 2015. PMID 26445332.
11. Radiation Emergency Medical Management. Cutaneous Radiation Syndrome. Accessed on 10/24/2026. Official source.