Cutaneous and local radiation injuries

Abstract

The threat of a large-scale radiological or nuclear (R/N) incident looms in the present-day climate, as noted most recently in an editorial in Scientific American (March 2021). These large-scale incidents are infrequent but affect large numbers of people. Smaller-scale R/N incidents occur more often, affecting smaller numbers of people. There is more awareness of acute radiation syndrome (ARS) in the medical community; however, ionising radiation-induced injuries to the skin are much less understood. This article will provide an overview of radiation-induced injuries to the skin, deeper tissues, and organs. The history and nomenclature; types and causes of injuries; pathophysiology; evaluation and diagnosis; current medical management; and current research of the evaluation and management are presented. Cutaneous radiation injuries (CRI) or local radiation injuries (LRI) may lead to cutaneous radiation syndrome, a sub-syndrome of ARS. These injuries may occur from exposure to radioactive particles suspended in the environment (air, soil, water) after a nuclear detonation or an improvised nuclear detonation (IND), a nuclear power plant incident, or an encounter with a radioactive dispersal or exposure device. These incidents may also result in a radiation-combined injury; a chemical, thermal, or traumatic injury, with radiation exposure. Skin injuries from medical diagnostic and therapeutic imaging, medical misadministration of nuclear medicine or radiotherapy, occupational exposures (including research) to radioactive sources are more common but are not the focus of this manuscript. Diagnosis and evaluation of injuries are based on the scenario, clinical picture, and dosimetry, and may be assisted through advanced imaging techniques. Research-based multidisciplinary therapies, both in the laboratory and clinical trial environments, hold promise for future medical management. Great progress is being made in recognising the extent of injuries, understanding their pathophysiology, as well as diagnosis and management; however, research gaps still exist.

Keywords: animal models; cutaneous radiation injury (CRI); cutaneous radiation syndrome (CRS); local radiation injury (LRI); medical countermeasures; nuclear; radiological.

Figure 1.

Early transient erythema in a porcine model (15 Gy) at 15 minutes post-radiation exposure. The scale on the right shows the temperature scale. Red areas are hotter, blue and green areas cooler.

Figure 2.

Gray scale ultrasound image of control (L) and irradiated tissue (R).

Figure 3.

Colorized version of Figure 2, illustrating edema fluid density in red.

Figure 4.

Pixel distribution in control tissue and in tissue after irradiation. The distribution in irradiated tissue is narrower and with a lower mean value, due to edema fluid making the medium more uniform. This shifts the distribution to the left. The x-axis is the pixel number (256 pixel gray scale) and the y-axis is the number of pixels with each gray scale value.

Figure 5.

Patient S on Day 27 after an accident with a 22-Ci Ir-192 source. Note blister on left index finger and generalized edema throughout the finger.

Figure 6.

A 12-MHz ultrasound view of the irradiated Patient S finger (proximal to distal, left to right). From the top, there is a black water density stand-off pad so that that the epidermis and dermis can be separated from the initial ultrasound pulse. From the stand-off pad downward, there is a thin epidermis, dermis, and then bone. Note the blister, necrotic base, and fluid density exudates in the substance of the bone. Inset: Graph of exponentially decreasing image entropy along the finger.

Figure 7

(a) Fluoroscopically-induced necrotic lesions on patient D’s back; (b) Thermography image of patient D. Red and white areas indicate increased temperature and perfusion; green and blue areas are indicative of decreased perfusion.

Figure 7

(a) Fluoroscopically-induced necrotic lesions on patient D’s back; (b) Thermography image of patient D. Red and white areas indicate increased temperature and perfusion; green and blue areas are indicative of decreased perfusion.

Figure 8.

Ultrasound image showing radiation fibrosis on patient D’s back.

Figure 9.

The affected worker from a radiological accident in Chilca in 2012 [26]. Progression of an LRI in a worker exposed to an Ir-192 source, gamma emitter. Picture 1: Hands of the patient 10 days after exposure, absorbed doses assigned to each finger, estimated by EPR from fingernails. Picture 2: Day 124 after exposure, the patient returned home with no symptoms. Picture 3: Day 572 after exposure, the patient presented a recurrence of the LRI, starting a year after the accident. Picture 4: Day 604 after exposure, due to the severe LRI and joint ankylosis, administration of MSC and surgery were applied (Pictures courtesy of Percy–IRSN and IAEA).

Figure 10.

Images of the local radiation injury in the left gluteus of the patient, and evolution of the lesion over ten days (Nueva Aldea Radiological Accident). (a) Image taken two days after exposure (16 December 2005). (b) Image taken five days after the exposure (19 December 2005). (c) Image taken six days after the exposure (20 December 2005). (d) Image taken 12 days after the exposure (26 December 2005) [97].

Figure 11.

An affected individual from a radiological accident in Ventanilla [102]. Progression of CRI/LRI in a worker exposed to an Ir-192 source (gamma emitter). Picture 1: Day 3 after exposure. Picture 2: Day 12 after exposure. Picture 3: Day 76 after exposure; Picture 4: Follow-up of the patient, day 1476 after exposure, after the dosimetry guided surgery (day 120 post exposure) and administration of MSC (Pictures courtesy of Dr. Alberto Lachos, Dr. German Mendoza and IAEA) [26].

Figure 12.

3-Dimensional visualization of a porcine CRI model: Combining CT imaging with radiation dosimetry data in an immersive environment creates a visual representation of underlying tissue topology, allowing for more accurate analysis to refine current modeling systems.