**Abstract**

The discovery of radiation has led to many advances. Guidelines have been created to minimize radiation exposure and treatment management following both unintentional and intentional exposure. The effects of radiation exposure on specific tissues varies. Tragic consequences can result, ranging from severe, acute injury to long- lasting effects that present years after the initial exposure. In this chapter we provide observations that demonstrate the importance of understanding guidelines to minimize radioactive exposure and the expectations and treatment management following exposure. For the safety and well-being of patients, health care professionals need to remain well-informed to minimize the risks of this tool.

**Keywords:** radiation injury, emergency care and treatment

### **1. Introduction**

Our understanding of toxicity associated with exposure to radiation has increased since the discovery of X-rays in 1895. X-rays were used to treat a variety of malignant and non-malignant diseases. The effects of radioactive exposure on specific tissues can vary. Radioactive particles destroy or impair tissue by generating free radicals that damage important molecular structures, such as DNA. Radiation exposure can lead to catastrophic consequences, ranging from severe, acute injury to long-lasting effects that manifest years after the initial exposure. This chapter provides observations that demonstrate the importance of understanding guidelines to minimize radioactive exposure, and the expectations and treatment management following exposure [1–3].

Exposure to radioactive particles is divided into intentional or unintentional causes. Notable intentional causes include the atomic weapons activated on Hiroshima and Nagasaki in Japan during World War II. The immediate injuries and fatalities were from the heat and mechanical force generated by the trauma and physical destruction. However, it became apparent that there were longer lasting consequences. Survivors in the surrounding area were exposed to high levels of radiation and suffered from acute toxicity injuries and organ failure. Many of those who did not succumb to the effects of acute toxicity were known to suffer lifelong chronic conditions, such as developmental problems in newborns and increased cancer risk [4–6].

Unintentional causes are usually the result of radiation exposure without intent to injure. These unintentional causes are typically related to the effects of radioactive materials utilized for energy or medical treatment. The first radiograph was taken in 1895 and early pioneers in the field were unaware of the consequences of exposure. Initial procedures were often associated with unintentional exposure and were fraught with numerous complications such as skin blistering, hair loss and systemic toxicity that we now know were due to radiation toxicity. These signs and symptoms were similar to those present in exposed workers in the first nuclear development programs, many of whom would later develop injuries and cancers as a consequence of their profession [7, 8].

Despite these risks, nuclear power continues to be used for its benefits. Fortunately, we now know much more about how to avoid and minimize radioactive exposure. Rigorous standards enforcing safe practices with radioactive material and the formation of numerous regulatory agencies such as the Nuclear Regulatory Commission are a testament to how far we have come [9]. However, accidents involving radioactive material do occur. In this chapter, we describe a brief history of well-known incidents involving unintended radioactive exposure, as well as the clinical consequences and care of the patient following exposure.

### **2. Unintended causes: nuclear accidents**

One of the most significant nuclear accidents in history was Chernobyl. On that day, a series of missteps during a routine safety check resulted in a massive explosion that sent a plume of radioactive material into the air for an entire week. The range of this explosion extended well beyond the immediate vicinity, exposing other parts of Europe to radioactive gas in the process. In addition to exposing civilians to the radioactive material, first responders also received significant radiation levels and thermal injury, many of which were lethal. More recently, the nuclear reactor in Fukushima, Japan experienced a meltdown following the 2011 tsunami in Japan. While there were no immediate casualties, there was lasting environmental damage and the long-term health consequences are yet to be fully understood [8]. These examples demonstrate the importance of proper safety measures and providing an effective response to nuclear accidents.

### **3. Acute toxicity**

Toxicity from radiation exposure can be divided into three types: acute, subacute and chronic/late. Acute radiation toxicity is defined as signs and symptoms ≤90 days following exposure. In a medical setting, treatment of acute exposure is quite common. During radiation therapy, radiation is targeted and delivered to tumors and management of side effects from the radiation exposure remains a mainstay of modern oncology.

The radioactive dose from these procedures is typically far less than the dose following unintended exposures outside of the clinical setting. The radiation treatment dose is usually fractionated, meaning the dose is given in intervals to reduce the short-term toxicity of the radioactive treatment. The clinical manifestations of acute toxicity following a radioactive accident may be much more severe than those typically encountered by most physicians and may warrant treatment in an emergency setting [4, 5].

**5**

*Radiation Injury and Emergency Medicine DOI: http://dx.doi.org/10.5772/intechopen.95262*

days of exposure [1, 4, 5].

in terms of clinical aspects, but emotionally as well.

Acute radiation toxicity involves many organ systems, including but not limited

to the central nervous, gastrointestinal, and cardiovascular systems. Cells with self-renewal potential may be able to recover better from radiation damage compared to those without such protective mechanisms. Self-renewal processes are often accelerated as a response to injury where slowly proliferative tissues cannot. However, if the exposure is given in a single fraction of high enough dose, this ability for self-renewal potential will be overwhelmed. For example, a single total body dose >10 Gy will result in death within days from numerous possible causes. Damage to the central nervous system will result in cerebrovascular syndrome, with uncontrollable swelling in neuromuscular tissue. Despite best supportive care there are no medical interventions to prevent death at this level of exposure. Damage to the gastrointestinal system results in severe diarrhea and associated fluid loss. The mechanism involves depletion of most stem cells within the gastrointestinal crypts. Since these stem cells are required to replace the mucosal surface, these mucosal surfaces will disappear a few days after exposure and there will be no barrier to prevent fluid loss or bacterial entrance into the bloodstream. As a result, patients will typically present with fever, nausea, vomiting, fatigue, anorexia, and severe hypotension. Doses of 4–5 Gy are enough to cause death from depleted stem cells in the hematopoietic system without support. Those that survive the initial depletion typically succumb to infection a month later due to depleted lymphocytes and other immune elements. These manifestations can occur minutes after exposure, with severity being proportional to dose and a sharp decrease in lymphocytes within two

Should the patient be exposed to doses below 4 Gy, symptomatic and best supportive treatment is recommended. Nausea and vomiting are the typical initial symptoms and should be treated with hydration. If the exposure dose is unknown, noting the time of onset of vomiting is important as exposure dose is inversely proportional to time to emesis. It is not uncommon for patients at low exposure doses to feel fine for a few weeks before the gastrointestinal and hematopoietic symptoms drive a patient to seek medical care. Upon initiation of care, isolation and contact inhibition is vital since infection is a major contributor towards death in these patients as depletion of the hematopoietic system occurs. Blood transfusion and antibiotics can be delivered to alleviate these issues. A patient will often also present with skin injury burns at the site of radiation exposure as epidermal and dermal injury associated with stem cell depletion can mimic and appear similar to a thermal injury. These injuries should be treated promptly, as they are easy routes for infection to occur, which can be devastating to a patient with a compromised hematopoietic system. In patients with high exposure doses, end of life care is a possible consideration. At an exposure of 5 Gy, only about half of patients will survive after 30 days. An exposure of 10 Gy is considered lethal regardless of medical interventions [1, 5, 6]. Treating patients following radiation exposure is not only challenging

Compounds that have been developed to reduce and even prevent the clinical manifestations following radiation exposure are called mitigators. These compounds work by altering the molecular response following radiation exposure. As such, a mitigator could inhibit lymphocyte recruitment at sites of radiation damage, increase proliferation of stem cells that would normally be inhibited by radiation exposure, or inhibit fibrosis. An example of a mitigator is Palifermin, a growth factor that stimulates cell growth in response to radiation exposure to reduce recovery time. Radioprotectors, on the other hand, are given before or immediately after radiation exposure to protect against the effects of radiation toxicity [10, 11]. Amifostone is one such radioprotector that has been approved by the FDA for reducing side effects from radiation therapy [12]. More mitigators and

#### *Radiation Injury and Emergency Medicine DOI: http://dx.doi.org/10.5772/intechopen.95262*

*Trauma and Emergency Surgery - The Role of Damage Control Surgery*

a consequence of their profession [7, 8].

**2. Unintended causes: nuclear accidents**

providing an effective response to nuclear accidents.

succumb to the effects of acute toxicity were known to suffer lifelong chronic conditions, such as developmental problems in newborns and increased cancer risk [4–6]. Unintentional causes are usually the result of radiation exposure without intent to injure. These unintentional causes are typically related to the effects of radioactive materials utilized for energy or medical treatment. The first radiograph was taken in 1895 and early pioneers in the field were unaware of the consequences of exposure. Initial procedures were often associated with unintentional exposure and were fraught with numerous complications such as skin blistering, hair loss and systemic toxicity that we now know were due to radiation toxicity. These signs and symptoms were similar to those present in exposed workers in the first nuclear development programs, many of whom would later develop injuries and cancers as

Despite these risks, nuclear power continues to be used for its benefits. Fortunately, we now know much more about how to avoid and minimize radioactive exposure. Rigorous standards enforcing safe practices with radioactive material and the formation of numerous regulatory agencies such as the Nuclear Regulatory Commission are a testament to how far we have come [9]. However, accidents involving radioactive material do occur. In this chapter, we describe a brief history of well-known incidents involving unintended radioactive exposure, as well as the

One of the most significant nuclear accidents in history was Chernobyl. On that day, a series of missteps during a routine safety check resulted in a massive explosion that sent a plume of radioactive material into the air for an entire week. The range of this explosion extended well beyond the immediate vicinity, exposing other parts of Europe to radioactive gas in the process. In addition to exposing civilians to the radioactive material, first responders also received significant radiation levels and thermal injury, many of which were lethal. More recently, the nuclear reactor in Fukushima, Japan experienced a meltdown following the 2011 tsunami in Japan. While there were no immediate casualties, there was lasting environmental damage and the long-term health consequences are yet to be fully understood [8]. These examples demonstrate the importance of proper safety measures and

Toxicity from radiation exposure can be divided into three types: acute, subacute and chronic/late. Acute radiation toxicity is defined as signs and symptoms ≤90 days following exposure. In a medical setting, treatment of acute exposure is quite common. During radiation therapy, radiation is targeted and delivered to tumors and management of side effects from the radiation exposure remains a

The radioactive dose from these procedures is typically far less than the dose following unintended exposures outside of the clinical setting. The radiation treatment dose is usually fractionated, meaning the dose is given in intervals to reduce the short-term toxicity of the radioactive treatment. The clinical manifestations of acute toxicity following a radioactive accident may be much more severe than those typically encountered by most physicians and may warrant treatment in an

clinical consequences and care of the patient following exposure.

**4**

**3. Acute toxicity**

mainstay of modern oncology.

emergency setting [4, 5].

Acute radiation toxicity involves many organ systems, including but not limited to the central nervous, gastrointestinal, and cardiovascular systems. Cells with self-renewal potential may be able to recover better from radiation damage compared to those without such protective mechanisms. Self-renewal processes are often accelerated as a response to injury where slowly proliferative tissues cannot. However, if the exposure is given in a single fraction of high enough dose, this ability for self-renewal potential will be overwhelmed. For example, a single total body dose >10 Gy will result in death within days from numerous possible causes. Damage to the central nervous system will result in cerebrovascular syndrome, with uncontrollable swelling in neuromuscular tissue. Despite best supportive care there are no medical interventions to prevent death at this level of exposure. Damage to the gastrointestinal system results in severe diarrhea and associated fluid loss. The mechanism involves depletion of most stem cells within the gastrointestinal crypts. Since these stem cells are required to replace the mucosal surface, these mucosal surfaces will disappear a few days after exposure and there will be no barrier to prevent fluid loss or bacterial entrance into the bloodstream. As a result, patients will typically present with fever, nausea, vomiting, fatigue, anorexia, and severe hypotension. Doses of 4–5 Gy are enough to cause death from depleted stem cells in the hematopoietic system without support. Those that survive the initial depletion typically succumb to infection a month later due to depleted lymphocytes and other immune elements. These manifestations can occur minutes after exposure, with severity being proportional to dose and a sharp decrease in lymphocytes within two days of exposure [1, 4, 5].

Should the patient be exposed to doses below 4 Gy, symptomatic and best supportive treatment is recommended. Nausea and vomiting are the typical initial symptoms and should be treated with hydration. If the exposure dose is unknown, noting the time of onset of vomiting is important as exposure dose is inversely proportional to time to emesis. It is not uncommon for patients at low exposure doses to feel fine for a few weeks before the gastrointestinal and hematopoietic symptoms drive a patient to seek medical care. Upon initiation of care, isolation and contact inhibition is vital since infection is a major contributor towards death in these patients as depletion of the hematopoietic system occurs. Blood transfusion and antibiotics can be delivered to alleviate these issues. A patient will often also present with skin injury burns at the site of radiation exposure as epidermal and dermal injury associated with stem cell depletion can mimic and appear similar to a thermal injury. These injuries should be treated promptly, as they are easy routes for infection to occur, which can be devastating to a patient with a compromised hematopoietic system. In patients with high exposure doses, end of life care is a possible consideration. At an exposure of 5 Gy, only about half of patients will survive after 30 days. An exposure of 10 Gy is considered lethal regardless of medical interventions [1, 5, 6]. Treating patients following radiation exposure is not only challenging in terms of clinical aspects, but emotionally as well.

Compounds that have been developed to reduce and even prevent the clinical manifestations following radiation exposure are called mitigators. These compounds work by altering the molecular response following radiation exposure. As such, a mitigator could inhibit lymphocyte recruitment at sites of radiation damage, increase proliferation of stem cells that would normally be inhibited by radiation exposure, or inhibit fibrosis. An example of a mitigator is Palifermin, a growth factor that stimulates cell growth in response to radiation exposure to reduce recovery time. Radioprotectors, on the other hand, are given before or immediately after radiation exposure to protect against the effects of radiation toxicity [10, 11]. Amifostone is one such radioprotector that has been approved by the FDA for reducing side effects from radiation therapy [12]. More mitigators and radioprotectors are expected to be approved as the need to protect against radiation toxicity increases. Although many compounds have been and are in development, no others to date are actively used in clinical practice and the role of both hematopoietic and mesenchymal transplant remains under investigation.
