COPY: Biology Chapter 2: Radiation Chemistry
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Questions and Answers

What is the study of the effects of ionizing radiation on living systems?

  • Radiobiology (correct)
  • Deterministic Effects
  • Radiation Chemistry
  • Radiotherapy

    • Which of the following is a type of effect of radiation on tissues and organs?

  • Deterministic Effect (correct)
  • Radiotherapy
  • Stochastic Effect
  • Acute Radiation Syndrome

    • What is the result of DNA changes caused by radiation?

  • Acute Radiation Syndrome
  • Free Radical Formation
  • Mutations (correct)
  • Radiotherapy

    • What is the term for the effects of radiation that occur at low doses and have a random probability of occurrence?

    <p>Stochastic Effects</p> Signup and view all the answers

    What is the term for the effects of radiation that occur at high doses and have a predictable outcome?

    <p>Deterministic Effects</p> Signup and view all the answers

    What is the term for the short-term effects of radiation on the body?

    <p>Short-Term Effects</p> Signup and view all the answers

    What is the term for the effects of radiation on the embryo or fetus?

    <p>Radiation Effects on Embryos and Fetuses</p> Signup and view all the answers

    What is the term for the use of radiation to treat diseases in the oral cavity?

    <p>Radiotherapy</p> Signup and view all the answers

    What is the typical duration of radiation therapy to the head and neck that can cause severe oral complications?

    <p>6 weeks</p> Signup and view all the answers

    Which salivary gland is most radiosensitive?

    <p>Parotid gland</p> Signup and view all the answers

    What is the typical outcome of a 60 Gy dose of radiation to the salivary glands?

    <p>Complete loss of saliva flow</p> Signup and view all the answers

    What is xerostomia?

    <p>Dry mouth</p> Signup and view all the answers

    What is the typical time course of oral complications after radiotherapy?

    <p>Most severe during the first few weeks, decreasing over time</p> Signup and view all the answers

    What are the long-term risks of radiation therapy to the head and neck?

    <p>Lifelong oral complications</p> Signup and view all the answers

    What is the dose range that the major salivary glands are sometimes unavoidably exposed to during radiotherapy for cancer in the oral cavity or oropharynx?

    <p>20 to 30 Gy</p> Signup and view all the answers

    What is the effect of radiation therapy on taste and healing of mucositis?

    <p>Recovery of taste, healing of mucositis</p> Signup and view all the answers

    What is a common complaint during the second or third week of radiotherapy?

    <p>Loss of taste acuity</p> Signup and view all the answers

    Which flavors are more severely affected when the posterior two thirds of the tongue is irradiated?

    <p>Bitter and acid</p> Signup and view all the answers

    What is the estimated decrease in taste acuity during radiotherapy?

    <p>By a factor of 1000 to 10,000</p> Signup and view all the answers

    How long does it typically take for taste loss to recover after radiotherapy?

    <p>60 to 120 days</p> Signup and view all the answers

    What is the primary cause of taste loss during radiotherapy?

    <p>Degeneration of taste buds</p> Signup and view all the answers

    Which part of the tongue is responsible for detecting sweet and salt flavors?

    <p>Anterior third</p> Signup and view all the answers

    What complication of radiotherapy can partly account for the reduction in taste acuity?

    <p>Hyposalivation</p> Signup and view all the answers

    Is taste loss during radiotherapy reversible?

    <p>Yes, it is reversible</p> Signup and view all the answers

    What is the characteristic of radiation caries that distinguishes it from other types of caries?

    <p>Rapid course and widespread attack</p> Signup and view all the answers

    What is the best method of reducing radiation caries?

    <p>Daily application of a viscous topical 1% neutral sodium fluoride gel</p> Signup and view all the answers

    What is a consequence of radiation caries on the periapical bone?

    <p>Increased risk of periapical inflammatory lesions</p> Signup and view all the answers

    What is the effect of radiation therapy on the salivary glands?

    <p>Decreased flow and pH</p> Signup and view all the answers

    What is a characteristic of teeth that have undergone radiation therapy?

    <p>They erupt, even if rootless</p> Signup and view all the answers

    What is the relationship between the dose of radiation and the severity of damage to the tooth?

    <p>The severity of damage is directly proportional to the dose of radiation</p> Signup and view all the answers

    What is the effect of radiation on the oral flora?

    <p>Increased growth of Streptococcus mutans, Lactobacillus, and Candida</p> Signup and view all the answers

    What is the characteristic of the lesions that develop in patients with radiation caries?

    <p>They may progress around the teeth circumferentially</p> Signup and view all the answers

    What is a characteristic of saliva in individuals with xerostomia?

    <p>Low concentration of Ca2+ ion</p> Signup and view all the answers

    What is essential for patients undergoing radiation therapy to prevent radiation caries?

    <p>All of the above</p> Signup and view all the answers

    What is the result of radiation on teeth, especially at doses greater than 30 Gy?

    <p>Flaking of enamel</p> Signup and view all the answers

    Why are teeth with gross caries or periodontal involvement often extracted before irradiation?

    <p>To prevent radiation-induced damage to surrounding tissues</p> Signup and view all the answers

    What is the primary damage to mature bone in the mandible or maxilla due to radiation?

    <p>Damage to the vasculature of the periosteum and cortical bone</p> Signup and view all the answers

    What is the characteristic of the most common type of radiation caries?

    <p>Widespread superficial lesions on buccal, occlusal, incisal, and palatal surfaces</p> Signup and view all the answers

    Why is patient cooperation in maintaining oral hygiene extremely important?

    <p>Because radiation caries is a lifelong threat</p> Signup and view all the answers

    What is the minimum dose of radiation that can cause destruction of teeth, especially in areas of occlusal loading or stress?

    <p>30 Gy</p> Signup and view all the answers

    Study Notes

    Effects of Ionizing Radiation on Living Systems

    • Radiobiology: The study of the effects of ionizing radiation on living systems.

    Effects of Radiation on Tissues and Organs

    • Stochastic effects: Effects of radiation that occur at low doses and have a random probability of occurrence.
    • Deterministic effects: Effects of radiation that occur at high doses and have a predictable outcome.
    • Acute effects: Short-term effects of radiation on the body.
    • Teratogenic effects: Effects of radiation on the embryo or fetus.

    Radiation Therapy in Oral Cavity

    • Radiation therapy: The use of radiation to treat diseases in the oral cavity.
    • Head and neck radiation therapy: Typically lasts 6-7 weeks and can lead to severe oral complications.

    Salivary Gland Effects

    • Parotid glands: Most radiosensitive salivary glands.
    • 60 Gy dose: Typically leads to irreversible destruction of salivary glands.
    • Xerostomia: Dry mouth, a common side effect of radiation therapy caused by salivary gland damage.

    Time Course of Oral Complications

    • Oral complications: Often arise 2-3 weeks after radiotherapy.
    • Long-term risks: Radiation caries, xerostomia, osteoradionecrosis.

    Radiation Dose and Oral Complications

    • Major salivary gland exposure: Often unavoidable during radiotherapy for oral or oropharyngeal cancer, typically in the range of 45-60 Gy.

    Taste and Healing

    • Taste sensitivity: Reduced after radiotherapy, especially for sweet and salty flavors.
    • Mucositis: Inflammation of the mucous membrane lining the mouth, causing pain and difficulty eating.
    • Taste recovery: Typically takes several months to a year.

    Oral Flora and Radiation Caries

    • Oral flora: Altered after radiotherapy, leading to an increase in acidogenic bacteria.
    • Radiation caries: Type of dental decay characterized by rapid progression and a "crater-like" appearance.
    • Periapical bone: Affected by radiation caries, leading to bone resorption and tooth loss.

    Radiotherapy Effects on Teeth

    • Teeth: Highly susceptible to damage from radiation therapy, especially at doses greater than 30 Gy.
    • Gross caries: Often extracted before irradiation to prevent complications.
    • Tooth structure: Weakens due to radiation, becoming more prone to fracture.
    • Oral hygiene: Extremely important for preventing complications.

    Osteoradionecrosis

    • Bone damage: The primary damage to mature bone in the mandible or maxilla due to radiation, leading to bone necrosis.
    • Minimum dose for destruction: Approximately 30 Gy.

    Key Findings

    • Radiation therapy: A vital treatment for head and neck cancers but has significant oral complications.
    • Xerostomia and radiation caries: Major concerns that require preventive measures.
    • Patient cooperation: Essential for successful management of oral complications.

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    Description

    This quiz covers the topics of radiation chemistry, deterministic effects on tissues and organs, and whole-body irradiation in biology.

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