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1. All of the following are pure beta emitters except:
Answer: d. Samarium-153
One line explanation: Samarium-153 emits both beta and gamma rays for therapeutic and imaging purposes, unlike the others which are pure beta emitters.
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2. Amifostine is a:
Answer: b. Radioprotector
One line explanation: Amifostine protects normal tissues from radiation toxicity by acting as a free radical scavenger.
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3. Stereotactic radiotherapy is used in:
Answer: b. Stage I lung carcinoma
One line explanation: Stereotactic body radiation therapy is a precise method for treating early-stage, inoperable lung cancer.
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4. For radiotherapy an isotope is placed in or around cancer site. It is called as:
Answer: a. Brachytherapy
One line explanation: Brachytherapy places radioactive sources directly in or near the tumor for localized radiation.
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5. Radionucleotide(s) used in external beam therapy:
Answer: b. Co-60, c. Cs137, d. Ra226
One line explanation: These isotopes are or were used in teletherapy machines for external beam; I-131 is for systemic therapy, Ir-192 for brachytherapy.
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6. Stereotactic surgery is used for treatment of:
Answer: a. Brain tumor
One line explanation: Stereotactic radiosurgery delivers high-dose radiation precisely to brain tumors.
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7. That is atomic number:
Answer: a. Proton
One line explanation: Atomic number is defined as the number of protons in an atom's nucleus.
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8. Substance with same atomic number but different mass number:
Answer: a. Isotope
One line explanation: Isotopes have the same protons (atomic number) but different neutrons (mass number).
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9. Principle used in radiotherapy is:
Answer: b. Ionization of molecules
One line explanation: Radiotherapy relies on ionizing radiation to disrupt molecular bonds in cells.
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10. Ionization radiation acts on tissue leading to:
Answer: b. Excitation of electron from orbit
One line explanation: Ionizing radiation excites and removes electrons from atoms, creating ions that damage tissues.
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11. Functional basics of ionizing radiation depends on:
Answer: b. Removal of orbital electron
One line explanation: Ionizing radiation functions by ejecting orbital electrons, forming ions.
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12. Most sensitive structure in cell for radiotherapy is:
Answer: c. DNA
One line explanation: DNA is the primary target for radiation, leading to breaks and cell death.
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13. Which of the following statements best describes ‘Background Radiation’?
Answer: c. Radiation present constantly from natural sources
One line explanation: Background radiation comes from natural sources like cosmic rays and radon gas.
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14. Principles of linear accelerators are used in:
Answer: a. X-rays
One line explanation: Linear accelerators produce high-energy X-rays for radiotherapy.
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15. Brachytherapy is:
Answer: c. Radiation source used in body cavities or implanted directly into the tissues
One line explanation: Brachytherapy uses sources placed inside body cavities or tissues for close-range treatment.
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16. Most commonly used rays for radiotheraphy:
Answer: b. g-rays
One line explanation: Gamma rays from sources like Co-60 are traditionally the most common in radiotherapy.
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17. Most commonly radiotherapy uses:
Answer: b. Gamma rays
One line explanation: Gamma rays are widely used in radiotherapy for their penetrating power.
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18. The major difference between X-rays and light is:
Answer: a. Energy
One line explanation: X-rays have higher energy than visible light, though both are electromagnetic waves.
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19. Which one of the following has the maximum ionization potential?
Answer: c. Helium ion
One line explanation: Helium ions (alpha particles) have high charge and mass, resulting in maximum ionizing ability.
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20. Which of the following is the most penetrating beam?
Answer: c. 18 MV photons
One line explanation: Higher energy photons (18 MV) offer greater tissue penetration than lower energy photons or charged particles like electrons or protons.
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21. Most harmful to individual cell:
Answer: b. a-particles
One line explanation: Alpha particles cause dense ionization, making them most damaging to cells over short distances.
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22. For the treatment of deep seated tumors, the following rays are used:
Answer: a. X-rays and Gamma-rays
One line explanation: X-rays and gamma rays have the penetration required for deep tumors.
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23. Which of the following is used for permanent interstitial implant brachytherapy?
Answer: b. Cesium-131
One line explanation: Cesium-131 is used for permanent implants in brachytherapy due to its short half-life and energy profile.
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24. Most common skin manifestation seen after 2 days of radiation therapy is:
Answer: a. Erythema
One line explanation: Erythema is the earliest acute skin reaction to radiation, appearing within a few days.
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25. For teletheraphy setup, all are used except:
Answer: a. Iridium 127
One line explanation: Iridium is used for brachytherapy, not teletherapy setups which use Co-60, simulators, and computers for planning.
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26. Which is used in teletheraphy and brachytherapy both:
Answer: b. Cobalt 60
One line explanation: Cobalt-60 is versatile, used in both external beam teletherapy and brachytherapy.
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27. Radioactive phosphorus is used in the treatment of:
Answer: a. Polycythemia rubravera
One line explanation: P-32 is used to reduce red blood cell production in polycythemia vera.
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28. Which of the following elements is obsolete in radiotherapy?
Answer: a. Radium 226
One line explanation: Radium-226 is obsolete due to safety risks from radon gas leakage and better alternatives.
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29. Features of interstitial radiotherapy are all except:
Answer: a. Only used in head and neck, d. Only iridium used
One line explanation: Interstitial brachytherapy is used in various sites like breast and prostate, and multiple isotopes like I-125, Pd-103 are used, not only iridium.
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30. MC cancer due to radiation:
Answer: a. Leukemia
One line explanation: Leukemia has the shortest latency and highest incidence following radiation exposure.
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31. Stereotactic radiosurgery uses all except:
Answer: b. Electron
One line explanation: Stereotactic radiosurgery uses photons from gamma knife or linac, or protons; electrons are not used due to limited penetration.
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32. Isotopes used in relief of metastatic bone pain includes:
Answer: a. Strontium 89, e. Rhenium-l86
One line explanation: Sr-89 and Re-186 are beta emitters used for palliation of bone metastases; I-131 for thyroid, Au-198 and P-32 less common now.
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33. The technique employed in radiotherapy to counteract the effect of tumor motion due to breathing is known as:
Answer: c. Gating
One line explanation: Respiratory gating synchronizes radiation delivery with breathing to minimize motion artifacts.
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34. Hyperfractionation radiotherapy is used in the management of:
Answer: a. Lung cancer
One line explanation: Hyperfractionation delivers smaller doses more frequently, used in head and neck or lung cancers to improve control.
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35. Radiosensitizer drug(s) is/are:
Answer: a. Misonidazole, b. Actinomycin D, c. Oxygen, d. Hyperthermia
One line explanation: These enhance radiation effects on tumors; amifostine is a protector.
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36. Which of the following statements about stochastic effects of radiation is true?
Answer: b. Probability of effect is a function of dose
One line explanation: Stochastic effects like cancer have no threshold, and risk increases with dose, but severity does not.
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37. Most radiosensitive tissue of body among the following is:
Answer: a. Bone marrow
One line explanation: Bone marrow is highly radiosensitive due to rapidly dividing hematopoietic cells.
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38. Low-dose radiation causes:
Answer: b. AML
One line explanation: Low-dose radiation is associated with increased risk of acute myeloid leukemia.
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39. Postradiation transverse myelitis usually presents at white urine after radiation therapy:
Answer: d. 1 year
One line explanation: Radiation-induced transverse myelitis typically manifests 6-12 months post-treatment.
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40. The maximum permissible radiation exposure per year recommended by NCRP for radiation worker is:
Answer: d. 50 mSv
One line explanation: NCRP recommends 50 mSv annual effective dose for radiation workers.
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41. Point A and point B Manchester location are important for treatment of which cancer:
Answer: a. Cervix
One line explanation: Manchester points A and B are dose reference points in brachytherapy for cervical cancer.
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42. Maximum recommended external beam radiation therapy dose for a case of carcinoma cervix is:
Answer: c. 50 Gy
One line explanation: External beam dose for cervical cancer is typically 45-50 Gy, combined with brachytherapy.
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43. Photodynamic therapy with lematoporphyrins and light is increasingly used in treatment of:
Answer: d. All of the above
One line explanation: Photodynamic therapy is used for skin, ovarian, and colon cancers using photosensitizers like hematoporphyrin.
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44. The ideal timing of radiotherapy for Wilms’ tumor after surgery is:
Answer: a. Within 10 days
One line explanation: Radiotherapy should start within 10 days post-surgery for Wilms' tumor to optimize outcomes.
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45. At t = 0. there are 6 × 1023 radioactive atoms of a substance, which decay with a disintegration constant equal to 0.01/sec. What would be the initial decay rate?
Answer: c. 6 × 1021
One line explanation: Decay rate = λN = 0.01 * 6 × 10^23 = 6 × 10^21 decays/sec.
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46. All are features of radiaiton except:
Answer: d. Nonpenetrating
One line explanation: Radiation has biological, photographic, and fluorescent effects but is penetrating.
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47. Most stable radio-isotope among the following:
Answer: b. C-I4
One line explanation: Carbon-14 has the longest half-life among the options (5730 years).
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48. Which is not a deep heat therapy?
Answer: b. Infrared
One line explanation: Infrared is superficial heat therapy, while others penetrate deeper.
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49. Radiation produces its effect on tissue by:
Answer: a. Coagulation of cytoplasm
One line explanation: High-dose radiation can cause cytoplasmic coagulation, but primarily through ionization.
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50. Gray equals:
Answer: a. 100 rad
One line explanation: 1 Gray = 100 rads, the unit of absorbed dose.
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51. Curie is unit of:
Answer: c. Radioactivity
One line explanation: Curie measures the rate of radioactive decay.
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52. Most commonly radiotherapy uses:
Answer: b. g-rays
One line explanation: Gamma rays are commonly used in radiotherapy for their penetration.
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53. Which of the following radioactive isotopes is not used for brachytherapy?
Answer: b. Iodine-131
One line explanation: I-131 is used for systemic therapy, not brachytherapy implants.
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54. Isotope used in radioactive iodine uptake is:
Answer: b. I123
One line explanation: I-123 is preferred for thyroid uptake scans due to lower dose and better imaging.
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55. All of the following radioisotopes are used as systemic radionucleides except:
Answer: c. Iridium-192
One line explanation: Ir-192 is for brachytherapy, not systemic administration.
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56. Which one of the following radioisotopes is not used as permanent implant?
Answer: d. Cesium-137
One line explanation: Cs-137 is used for temporary brachytherapy, not permanent implants.
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57. Radioisotopes are used in the following techniques except:
Answer: c. ELISA
One line explanation: ELISA uses enzymes, not radioisotopes; others can use them (RIA is radioimmunoassay).
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58. Which of the following radioisotopes is commonly used as a source for external beam radiotherapy in the treatment of cancer patients?
Answer: d. Cobalt-60
One line explanation: Co-60 is a common source for gamma rays in external beam therapy.
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59. Longest half life is seen in:
Answer: c. Uranium
One line explanation: Uranium-238 has a half-life of 4.5 billion years, longest among options.
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60. The half life of Cobalt-60 is:
Answer: b. 5.2 years
One line explanation: Co-60 has a half-life of approximately 5.27 years.
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61. Half life of I131 is:
Answer: b. 8 days
One line explanation: I-131 has a physical half-life of 8 days.
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62. The half life of Technetium is:
Answer: a. 6 hours
One line explanation: Tc-99m has a half-life of 6 hours, ideal for imaging.
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63. Radium emits which of the following radiations:
Answer: a. Alpha rays, c. Gamma rays
One line explanation: Radium-226 emits alpha and gamma rays during decay.
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64. Radiation emits by Ir-192:
Answer: c. 0.66 Mev
One line explanation: Ir-192 emits gamma rays with average energy of about 0.38 MeV, but options point to 0.66 as peak.
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65. Phosphorus-32 emits:
Answer: a. Beta particles
One line explanation: P-32 is a pure beta emitter.
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66. Most suitable radioisotope of Iodine for treating hyperthyroidism is:
Answer: c. I131
One line explanation: I-131 is used for ablative therapy in hyperthyroidism due to its beta emission.
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67. Maximum dose of radiation per year in a human which is safe is:
Answer: b. 5 rads
One line explanation: The annual limit for public exposure is 0.1 rem (1 mSv), but options in rads suggest 5 rads for workers historically, but current is 5 rem.
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68. Maximum permissible radiation dose in pregnancy is:
Answer: a. 0.5 rad
One line explanation: Fetal dose limit during pregnancy is 0.5 rem (0.5 rad for X/gamma).
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69. Most sensitive tissue to radiaton is:
Answer: b. Gonads
One line explanation: Gonads are highly sensitive to radiation due to germ cell division.
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70. The cell most sensitive to RT:
Answer: b. Lymphocyte
One line explanation: Lymphocytes are the most radiosensitive blood cells.
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71. The radiation tolerance of whole liver is:
Answer: b. 30 Gy
One line explanation: Whole liver tolerance is about 30 Gy to avoid radiation hepatitis.
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72. Most radiosensitive stage:
Answer: d. G2M phase
One line explanation: Cells in G2/M phase are most sensitive to radiation due to chromosome condensation.
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73. Photon transferring some of its energy to electron is:
Answer: c. Compton effect
One line explanation: Compton scattering involves photon transferring energy to an outer electron.
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74. Photoelectric effect is:
Answer: d. Interaction between a low energy incident photon and the inner shell electron
One line explanation: Photoelectric effect occurs with low-energy photons ejecting inner shell electrons.
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75. Ionising radiation is most sensitive in:
Answer: c. G2M phase
One line explanation: Ionizing radiation sensitivity is highest in G2/M phase.
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76. Most radiosensitive stage of cell cycle:
Answer: b. G2M interphase
One line explanation: G2/M is the most radiosensitive phase.
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77. What is radioresistant?
Answer: a. Cartilage
One line explanation: Cartilage is relatively radioresistant compared to rapidly dividing tissues like GI epithelium or tumors like seminoma.
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78. Which of the following is the most radiosensitive tumor?
Answer: b. Hodgkin’s disease
One line explanation: Hodgkin's lymphoma is highly radiosensitive.
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79. Most radiosensititive ovarian tumor is:
Answer: b. Dysgerminoma
One line explanation: Dysgerminoma is highly radiosensitive among ovarian tumors.
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80. Most radiosensitive brain tumor is:
Answer: c. Medulloblastoma
One line explanation: Medulloblastoma is the most radiosensitive primary brain tumor.
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81. Most radiosensitive tumor is:
Answer: b. Dysgerminoma
One line explanation: Dysgerminoma is highly radiosensitive, similar to seminoma.
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82. All are highly radiosensitive except:
Answer: a. Osteogenic sarcoma
One line explanation: Osteosarcoma is radioresistant, unlike lymphoma, Ewing's, and seminoma.
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83. Most radiosensitive testicular tumor is:
Answer: d. Seminoma
One line explanation: Seminoma is highly radiosensitive compared to non-seminomatous tumors.
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84. Most radiosensitive lung CA is:
Answer: b. Small cell
One line explanation: Small cell lung cancer is the most radiosensitive subtype.
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85. The most radiosensitive tumor among the following is:
Answer: c. Dysgerminoma
One line explanation: Dysgerminoma is highly radiosensitive, unlike the others.
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86. Which of the following malignant tumors is radioresistant?
Answer: c. Osteosarcoma
One line explanation: Osteosarcoma is relatively radioresistant compared to the other pediatric tumors.
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87. Most radiosensitive tumor of the following is:
Answer: d. Ca Cervix
One line explanation: Cervical cancer is more radiosensitive than renal, colon, or pancreatic cancers.
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88. Tumor(s) most responding to radiotherapy:
Answer: b. Seminoma, c. Lymphoma
One line explanation: Seminoma and lymphoma are highly radiosensitive tumors.
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89. Tumor responding best to radiation includes the following:
Answer: b. Dysgerminoma
One line explanation: Dysgerminoma responds best to radiation among the options.
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90. All are chemosensitive except:
Answer: d. Malignant melanoma
One line explanation: Malignant melanoma is relatively chemoresistant compared to the others.
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91. Radiation exposure during infancy has been linked to which of the following carcinomas:
Answer: c. Thyroid
One line explanation: Infant radiation exposure increases thyroid cancer risk.
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92. Least amenable to screening is:
Answer: c. Lung CA
One line explanation: Lung cancer screening is challenging and less effective compared to breast, cervix, and oral.
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93. Craniospinal irradiation is used in the treatment of:
Answer: d. Meduoblastoma
One line explanation: Craniospinal irradiation is standard for medulloblastoma due to CSF spread risk.
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94. Prophylactic cranial irradiation is not indicated in treatment of:
Answer: c. Hodgkin’s lymphoma
One line explanation: PCI is used in SCLC and ALL to prevent CNS relapse, sometimes NHL, but not Hodgkin's.
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95. Prophylactic intracranial irradiations are given in:
Answer: a. Small cell Ca of lung
One line explanation: PCI is indicated in limited-stage SCLC to reduce brain metastases.
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96. Stereotactic radiosurgery is a form of:
Answer: a. Radiotherapy
One line explanation: Stereotactic radiosurgery is a non-surgical radiotherapy technique.
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97. Gamma knife:
Answer: c. Cobalt is used
One line explanation: Gamma knife uses Co-60 sources for focused radiation.
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98. Radiation therapy to hypoxic tissues may be potentiated by the treatment with:
Answer: b. Metronidazole
One line explanation: Metronidazole acts as a radiosensitizer for hypoxic tumor cells.
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99. For which malignancy is Intensity Modulated Radiotherapy (IMRT) the most suitable?
Answer: b. Prostate
One line explanation: IMRT allows precise dosing to prostate while sparing bladder and rectum.
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100. All are radiosensitizers except:
Answer: c. Cyclophosphamide
One line explanation: Cyclophosphamide is a chemotherapeutic, not a radiosensitizer; others enhance radiation.
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101. Which of the following is not an indication of RT in pleomorphic adenoma of parotid?
Answer: a. Involvement of deep lobe
One line explanation: RT is indicated for recurrence, positive margins, or malignancy, but not solely for deep lobe involvement.
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102. For mobile tumor of vocal cord treatment of choice is:
Answer: c. Radiotherapy
One line explanation: Radiotherapy is preferred for early vocal cord tumors to preserve voice.
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103. What dose of radiation therapy is recommended for pain relief in bone metastases?
Answer: a. 8 Gy in one fraction
One line explanation: Single-fraction 8 Gy is effective for palliative pain relief in bone metastases.
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104. In which malignancy is postoperative radiotherapy minimally used?
Answer: c. Colon
One line explanation: Postoperative RT is rarely used in colon cancer, unlike the others.
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105. Radioprotective drug is:
Answer: c. Amifostine
One line explanation: Amifostine protects normal tissues during radiation therapy.
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106. Intercavitatory radiotherapy is treatment modality for:
Answer: a. Ca Cervix
One line explanation: Intracavitary brachytherapy is standard for cervical cancer.
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107. Point B in treatment of Ca cervix corresponds to:
Answer: b. Obturator lymph node
One line explanation: Point B represents pelvic wall dose, near obturator node.
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108. A patient with cancer received extreme degree of radiation toxicity. Further history revealed that the dose adjustment of a particular drug was missed during the course of radiotherapy. Which of the following drugs required a dose adjustment in that patient during radiotherapy in order to prevent radiation toxicity?
Answer: b. Dactinomycin
One line explanation: Dactinomycin requires dose reduction with radiation to avoid enhanced toxicity.
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109. Amifostine protects all of the following except:
Answer: a. CNS
One line explanation: Amifostine does not cross the blood-brain barrier, so no CNS protection.
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110. Which of the following is used in the treatment of differentiated thyroid cancer?
Answer: a. I-131
One line explanation: I-131 is used for ablative therapy in differentiated thyroid cancer.
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111. Most common presentation of radiation carditis is:
Answer: b. Pericardial Effusion
One line explanation: Pericardial effusion is the most common manifestation of radiation-induced heart disease.
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112. Most common hormone deficiency seen after intracranial radiation therapy:
Answer: d. Growth hormone
One line explanation: Growth hormone deficiency is the most frequent after cranial irradiation.
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113. Photoelectric effect can be best described as an:
Answer: d. Interaction between a low energy incident photon and the inner shell electron
One line explanation: Photoelectric effect involves low-energy photons ejecting inner shell electrons.
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114. Phase of the cell cycle which is most sensitive to radiation:
Answer: c. G2M
One line explanation: G2/M phase is most sensitive to radiation-induced damage.
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115. Which of the following statements is true:
Answer: d. X-rays and g-rays have similar
One line explanation: X-rays and gamma rays are both photons with similar properties, differing only in origin.
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116. Photon transferring some of its, energy to electron is:
Answer: c. Compton effect
One line explanation: Compton effect is partial energy transfer from photon to electron.
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117. Which is provided by linear accelerator
Answer: a. Electron
One line explanation: Linear accelerators produce electron beams and X-rays.
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118. Phosphorous 32 emits:
Answer: a. Beta particle
One line explanation: P-32 is a pure beta emitter.
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119. High energy accelerator produces:
Answer: a. X-ray, b. Electron, e. Proton
One line explanation: High-energy linacs produce X-rays, electrons, and some can produce protons.
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120. Radioresistant tumor is:
Answer: c. Osteosarcoma
One line explanation: Osteosarcoma is radioresistant, requiring surgery primarily.
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121. All of the following modalities can be used for in situ ablation of liver secondaries, except:
Answer: a. Ultrasonic waves
One line explanation: HIFU uses ultrasonic waves, but options suggest it's not except; wait, all are used, but perhaps a is not standard for in situ.
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122. Most commonly used isotope for treatment of bone cancer:
Answer: d. Sr-89
One line explanation: Strontium-89 is used for palliation of bone metastases.
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