MCQs on Radiation Biology and Safety - Part 1

# Among the natural radiation, the one that contributes to more radiation exposure of general population:
A. Cosmic
B. Terrestrial
C. Radon
D. Consumer products

# X rays cause radiation damage primarily by their property of:
A. Penetration
B. Radioactivity
C. Electromagnetic induction
D. Ionisation


# The somatic non stochastic effect of radiation is seen:
A. As effects on the body irradiated
B. As effect of mutation
C. As hereditary phenomenon
D. All of the above

# Which of the following is an example of a deterministic effect of radiation?
A. Radiation induced cancer
B. Mucositis
C. Genetic and somatic mutations
D. Tumor induction

# Which of the following is a form of stochastic effect of radiation?
A. Acute radiation syndrome
B. Embryological and fetal effects
C. Carcinogenesis and genetic effects
D. Shortened life span

# Radiation-induced thyroid cancer is the result of which type of radiation?
A. Somatic
B. Genetic
C. Teratogenic
D. All of the above

# The residual biological damage that remains following an exposure to radiation is called:
A. Direct effect
B. Indirect effect
C. Cumulative effect
D. Tolerance

# Most sensitive phase in cell division to radiation is:
A. G1 phase and S2 phase
B. S1 phase and S2 phase
C. M phase and G2 phase
D. G1 and G2 phase

# One arm of chromatid is affected by radiation in _______ phase.
A. G
B. Mid and late S
C. Both of the above
D. G or early S

# Radiation damage to a cell's DNA can result in all conditions EXCEPT:
A. Mitotic acceleration
B. Cell death
C. Carcinogenesis
D. Gene mutation

# The structure of protein least affected by radiation is:
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure

# Most susceptible to radiations are:
A. Nucleic acids
B. Nerve cells
C. Muscle cells
D. Epithelial cells

# Which of the following cell organelle are not affected by radiation induced mechanisms?
A. DNA
B. Cell membrane
C. Mitochondria
D. RNA

# Which is not a mechanism of reproductive death?
A. Apoptosis
B. DNA damage
C. Bystander effect
D. Chromosome aberrations

# Chromosomal damage is maximum during radiotherapy when there is damage to:
A. Centrosome
B. Telomere
C. Autosome
D. Kinetochore

# Which of the following is the most radiosensitive cell in the body?
A. Basal layer
B. Muscle cell
C. Lymphoid tissue
D. RBC

# Sensitivity of a body tissue to radiation is dependent on:
A. Blood flow
B. Mitotic rate of cells
C. Iron content
D. Protein content of cells

# Most radiosensitive cells are:
A. Vegetative intermitotic cells
B. Reverting post mitotic cells
C. Differential intermitotic cells
D. Fixed postmitotic cells

# The following is at more risk from exposure of a dental X ray:
A. Bone marrow
B. Breast
C. Brain
D. Thyroid

# Which of the following is most radioresistant?
A. Tongue
B. Skin
C. Red bone marrow
D. Thyroid gland

# Fixed post mitotic cells are:
A. Spermatocytes
B. Fibroblasts
C. Endothelial cells
D. Muscle

# The most radiosensitive cells in the body are:
A. Endothelial cells
B. Epithelial cells
C. Red blood cells
D. White blood cells

# The most radioresistant organ is:
A. Cartilage
B. Gonads
C. Lungs
D. Lymphoid

# Critical organs which are more sensitive to radiation are:
A. Skin and thyroid
B. Eyes, salivary glands
C. Red bone marrow and gonads
D. All of the above

# Which of the following are most sensitive to X ray?
A. Tooth buds and salivary glands
B. Nerve and muscle tissue
C. Hair and nails
D. Cartilage

# The cells which are least susceptible to radiation are:
A. Fibroblasts
B. Osteoblasts
C. Lymphocytes
D. Erythrocytes

# Most radioresistant cells are:
A. Lymphocytes
B. Granulocytes
C. Muscle cells
D. Connective tissue cells

# Least radiosensitive cells are:
A. Bone cells, muscle, nerve
B. Nerve, muscle, RBC
C. WBC, fibroblast, osteoblast
D. Nerve, muscle, cartilage

# Which of the following is most sensitive to radiation induced cancer?
A. Nerves
B. Female Breast
C. Thyroid
D. Skin

# In radiobiology, the 'latent period' represents the period of time between:
A. Cell rest and cell mitosis
B. The first and last doe in radiation therapy
C. Film exposure and image development
D. Radiation exposure and its biological effects (onset of symptoms)

# The skin of a patient undergoing radiotherapy will show ________ after two weeks.
A. Erythema
B. Depigmentation
C. Radiation induced carcinomas
D. No change

# Reduced salivary flow following irradiation is dose dependent. At what dose does the flow reach essentially zero?
A. 4000 rads
B. 5000 rads
C. 6000 rads
D. 7000 rads

# Which of the following is not a complication of therapeutic radiation?
A. Mucositis
B. Xerostomia
C. Cervical caries
D. Paraesthesia of the tongue

# Radiation caries is caused by irradiation of:
A. Salivary glands
B. Enamel
C. Enamel and dentin
D. Oral mucosa

# The most common type of radiation caries is:
A. Cervical surface involvement of teeth
B. Widespread superficial lesion attacking buccal, occlusal, incisal and palatal surfaces
C. Spreading to occlusal and palatal surfaces
D. Dark pigmentation of the entire crown

# Complication of irradiation of mouth may include all EXCEPT:
A. Accelerated caries activity
B. Caries in unusual sites
C. Accelerated periodontal diseases
D. Xerostomia

# Radiation injury to the haemopoietic system of the bone marrow occurs when the whole body exposure ranges between:
A. 50-100 rads
B. 200-1000 rads
C. 1000-5000 rads
D. 10000 rads and above

# In acute radiation syndrome severe haematopoietic symptoms are seen at dose:
A. 2 to 4 Gy
B. 4 to 7 Gy
C. 7 to 15 Gy
D. 50 Gy

# A patient requires tooth extractions from an area that has been subjected to radiation therapy. Which of the following represents the greatest danger to this patient?
A. Alveolar osteitis
B. Osteoradionecrosis
C. Prolonged healing
D. Fracture of the mandible

# The side effect on the tissues exposed to the radiation depends upon the:
A. Lymphatic obstruction
B. Repairing capacity of the tissue
C. Damage to microvasculature
D. Inflammation at the radiation site

# Osteoradionecrosis is due to:
A. Endarteritis of blood vessels
B. Damage to periosteum
C. Damage to lymphatics
D. All of the above

# Osteoradionecrosis results from:
A. Infection, trauma, radiation
B. Radiation, trauma, infection
C. Trauma, radiation, infection
D. None of the above

# The recommended time gap between the radiation and surgery to avoid osteoradionecrosis:
A. 4-6 weeks after radiotherapy
B. 6-12 months after radiotherapy
C. Immediately after radiotherapy
D. Any time during course of therapy

# Marx-University of Miami protocol for osteoradionecrosis is related to:
A. High dose antibiotic therapy
B. Hyperbaric oxygen therapy
C. Both A and B
D. None of the above

# Months or years following radiotherapy, the irradiated oral mucosa:
A. Undergoes necrosis
B. Develops Candidiasis
C. Becomes atrophic
D. Develops granulomatosis

# A patient who has been given tumoricidal dose of radiotherapy recently reports to dental clinic with painful carious exposed mandibular first molar with periapical abscess. The treatment of choice should be:
A. Extraction of the offending tooth
B. Root canal treatment if possible
C. No treatment should be given
D. Incision and drainage of abscess

# In treatment of oral cancers, the fraction of total dose given in each appointment is in the range of:
A. 150 rad
B. 300 rad
C. 400 rad
D. 500 rad

# Fractionalisation of radiation dose for cancer patients is done:
A. To permit recovery of normal cells during radiation
B. To deliver maximum radiation within short time
C. To deliver increments of radiation of different types
D. All of the above

# Treatment of carcinoma with radiation by inserting internal implants in the body is known as:
A. Teletherapy
B. Brachytherapy
C. Celetherapy
D. Radiation therapy

# Which of these factors has no effect on response of cells to irradiation?
A. Linear energy transfer
B. Oxygen
C. Image receptor used
D. Dose rate

# Radiation treatment employed in deep seated cancer cases is:
A. X ray photon
B. Electron
C. Neutron
D. Proton

# Medical linear accelerator produce:
A. Neutrons + Electrons
B. Protons + Neutrons
C. Photons + Protons
D. Photons + Electrons

# The technical employed in radiotherapy to counteract the effect of tumor motion due to breathing is known as:
A. ART technique
B. Modulation
C. Gating
D. Shunting

# Following exposure, the X rays interact with patient tissues within:
A. 10^-13 seconds
B. 10^10 seconds
C. 10^+13 seconds
D. 10^-20 seconds

# Mitotic delay is longer with:
A. Smaller dose
B. Moderate dose
C. Large dose
D. Both A and B

# The medical specialty in which there is statistically higher incidence of leukemia is:
A. Dentistry
B. Internal medicine
C. Radiology
D. Anaesthesiology

# Effective dose from diagnostic intraoral X ray examination using rectangular collimation for 'F' speed film is:
A. 30 microSv
B. 5 microSv
C. 171 microSv
D. 35 microSv

# Effective dose of X ray exposure for an adult in an IOPA:
A. 200 micro Sv
B. 5000 micro Sv
C. 50 micro Sv
D. 0.5 micro Sv