Radiation

Radiation

Q. 1

Which of the following statements best describes ‘Background Radiation’

 A

Radiation in the background of nuclear reactors

 B

Radiation in the background during radiological investigations

 C

Radiation present constantly from natural sources 

 D

Radiation from nuclear fall out

Q. 1

Which of the following statements best describes ‘Background Radiation’

 A

Radiation in the background of nuclear reactors

 B

Radiation in the background during radiological investigations

 C

Radiation present constantly from natural sources 

 D

Radiation from nuclear fall out

Ans. C

Explanation:

C i.e. Radiation present constantly from natural sources

Back ground radiation is a low level, wide spread (ubiquitous), constantly present radiation from natural sources that is usually not detrimental to lifeQ.


Q. 2

True about Electromagnetic radiation:

 A

Pair production occur for low energy

 B

Infrared is a EM radiation

 C

Compton scattering occur for intemediate energy

 D

b and c

Q. 2

True about Electromagnetic radiation:

 A

Pair production occur for low energy

 B

Infrared is a EM radiation

 C

Compton scattering occur for intemediate energy

 D

b and c

Ans. D

Explanation:

B i.e. Infrared is a EM radiation; C i.e. Compton scattering occur for intemediate energy


Q. 3

Which of the following best estimates the amount of radiation delivered to an organ in the radiation field:

 A

Absorbed dose

 B

Equivalent dose

 C

Effective dose

 D

Exposure dose

Q. 3

Which of the following best estimates the amount of radiation delivered to an organ in the radiation field:

 A

Absorbed dose

 B

Equivalent dose

 C

Effective dose

 D

Exposure dose

Ans. A

Explanation:

A i.e. Absorbed dose 

Amount of radiation delivered to an organ is defined as absorbed doseQ. Whereas equivalent dose is a measure of biological damage caused by the absorbed dose depending on the relative effectiveness of type of radiation; and effective dose is a measure to assess the risk of carcinogenesis & genetic defect by calculating an imaginary total body dose depending on equivalent dose for each organ and relative sensitivity of each organ to radation.


Q. 4

Which of the following is the most ionizing radiation:

 A

Alpha

 B

Beta

 C

X-Ray

 D

Gamma

Q. 4

Which of the following is the most ionizing radiation:

 A

Alpha

 B

Beta

 C

X-Ray

 D

Gamma

Ans. A

Explanation:

A i.e. Alpha


Q. 5

Functional basis of ionising radiation depends on:

 A

Functional basis of ionising radiation depends on:

 B

Removal of orbital electron

 C

Linear energy transfer

 D

Adding orbital electron

Q. 5

Functional basis of ionising radiation depends on:

 A

Functional basis of ionising radiation depends on:

 B

Removal of orbital electron

 C

Linear energy transfer

 D

Adding orbital electron

Ans. B

Explanation:

B i.e. Removing orbital electrons


Q. 6

Radiation produces its effect on tissue by

 A

Coagulation of cytoplasm

 B

Increasing the temperature

 C

Charring of nucleoprotein

 D

Hydrolysis

Q. 6

Radiation produces its effect on tissue by

 A

Coagulation of cytoplasm

 B

Increasing the temperature

 C

Charring of nucleoprotein

 D

Hydrolysis

Ans. C

Explanation:

C i.e. Charring of nucleoprotein

Radiotherapy is treatment of malignant tumors with ionizing radiation (m.c. y rays)Q ; which causes excitation or ionization (ejection of electron from orbit) of electronQ and kills tumor cells by producing double strand breaks in DNA (direct) or free radicles (indirect). So ionizing Radio Therapy acts (on tissue) by- Excitation of electron (to higher energy levels without actual ejection) – and Ionization of electron (Removal of orbital e-).

Ionizing radiation is of two types – electromagnetic on) and particulate radiation.

Type

Mass

Charge

Comment

Electromagnetic

 

 

X Ray & y ray do

X Ray

0

0

not differ except in

Gamma Ray

0

0

the source. y rays

are produced

intranuclearly and

 

 

 

X rays are

produced

extranuclearly (i.e.

mechanical)

Particulate

 

 

 

Electron (e)

e

-1

‑

Proton (p)

2000xe

+1

Exhibit Bragg peak

 

 

 

(most of energy is

given abruptly

causing ionization)

Neutron (n)

2000xe

0

Can’t be

accelerated by an

electrical field

Alpha particle

2p+2n

+2

Helium Particle

 

(8000xe)

 

(2p+2n)

The biological effects produced by a radiation is quantified as relative biological effectiveness (RBE), which compairs them to effects produced by 250KV photon radiation as a standard.

RBE value depends on Linear energy transfer (LET; is amount of ionization occurring per unit length of radiation tract), dose, dose rate & nature of biological system.

Absorption of energy from radiation in tissue leads to ionization &/or excitation leading to various biological effects Q.

–  Radiation must produce double-strand breaks (not single-strand) in DNA to kill a cell. It can indirectly kill by producing free radicles.

Chromosomal abnormalities occur in cells irradiated in G1 Phase of cell cycle before doubling of genetic material.

Chromatid aberration occurs in cells irradiated in G2 Phase. Most sensitive phase to radiation is M> G2M interphaseQ. Most resistant phase to radiation is end of S phaseQ. Lymphocyte analysis provides evidence of recent total body exposure.

— Ionization radiation (most commonly y rays/X rays) is used for RT. It causes excitation and ionization of electron from orbit Vt double strand break in DNA (i.e. charring of nucleoprotein) and free radical production in tissueQ.


Q. 7

Radium emits which of the following radiations:

 A

Alpha rays

 B

Beta rays

 C

Gamma rays

 D

All

Q. 7

Radium emits which of the following radiations:

 A

Alpha rays

 B

Beta rays

 C

Gamma rays

 D

All

Ans. D

Explanation:

A i.e. α rays; B i.e. β-rays; C i.e. γ -rays


Q. 8

Maximum permissible radiation dose in pregnancy is:

 A

0.5 rad.

 B

1.0 rad.

 C

1.5 rad.

 D

rad.

Q. 8

Maximum permissible radiation dose in pregnancy is:

 A

0.5 rad.

 B

1.0 rad.

 C

1.5 rad.

 D

rad.

Ans. A

Explanation:

A i.e. 0.5 rad 

–   Maximal permissible radiation dose: is the dose of radiation which if received each year for a 50 years working life time would not be expected to produce any harmful effect.

The recommended occupational limit of maternal exposure to radiation from all sources is 500 milli rads (0.5 rads)Q for entire 40 weeks of gestation.

– 10 days rule advices that any X Ray examination involving the abdomen of a women of child bearing age should be carriedout with the 10 days of menstruation.Q

Fetus is most sensitive to the effects of radiation during 8-15 weeks of gestationQ.


Q. 9

Most common hormone deficiency seen after intracranial radiation therapy ‑

 A

Prolactin

 B

Gonadotropins

 C

ACTH

 D

Growth hormone

Q. 9

Most common hormone deficiency seen after intracranial radiation therapy ‑

 A

Prolactin

 B

Gonadotropins

 C

ACTH

 D

Growth hormone

Ans. D

Explanation:

D i.e. Growth hormone 

Growth hormone deficiency is most common endocrinal complication of intracranial radiotherapyQ.

Endocranial dysfunction in intracranial radiotherapy

Hypopituitarism frequently occurs after exposure of hyothalmus or pituitary gland to therapeutic radiation; especially in children & adolescent. It develops usually after 5- 15 years and reflects hypothalmic damage rather than absolute destruction of pituitary cells. Irradiation dose & time interval after completion of radiotherapy strongly correlates with the development of hormonal abnormalities.


Q. 10

MC cancer due to Radiation :

 A

Leukaemia

 B

Bronchogenic Ca

 C

Thyroid Ca

 D

Breast cancer

Q. 10

MC cancer due to Radiation :

 A

Leukaemia

 B

Bronchogenic Ca

 C

Thyroid Ca

 D

Breast cancer

Ans. A

Explanation:

A i.e., Leukemia


Q. 11

Late effects of radiation thearpy:

 A

Mucositis

 B

Enteritis

 C

Nausea and vomiting

 D

a and b

Q. 11

Late effects of radiation thearpy:

 A

Mucositis

 B

Enteritis

 C

Nausea and vomiting

 D

a and b

Ans. D

Explanation:

A i.e. Mucositis; B i.e. Enteritis


Q. 12

Most common skin manifestation seen after 2 days of radiation therapy is‑

 A

Erythema

 B

Atopy

 C

Hyperpigmentation

 D

Dermatitis

Q. 12

Most common skin manifestation seen after 2 days of radiation therapy is‑

 A

Erythema

 B

Atopy

 C

Hyperpigmentation

 D

Dermatitis

Ans. A

Explanation:

A i.e. Erythema

Most common early (acute) manifestation of local skin reaction is erythemaQ which is followed by desquamation


Q. 13

Which of the following statements about ‘Stochastic effects’ of radiation is true

 A

Severity of effect is a function of dose

 B

Probability of effect is a function of dose

 C

It has a threshold

 D

Erythema and cataract are common examples

Q. 13

Which of the following statements about ‘Stochastic effects’ of radiation is true

 A

Severity of effect is a function of dose

 B

Probability of effect is a function of dose

 C

It has a threshold

 D

Erythema and cataract are common examples

Ans. B

Explanation:

B i.e. Probability of effect is a function of dose

The probability of occurrence of late stochastic effects (like cancer & hereditary genetic defects) increases with increasing absorbed cumulative doseQ. However there is no threshold dose below which it is certain that the stochastic effect can not occur.

Effects of Radiation

Feature

Acute (non stochastic) deterministic Effects

Late Stochastic Effect

Threshold dose

below which it

does not occur

Present

Absent/No(2

Dose (exposure)

& effect

relationship

Clear

The severity (magnitude) of effect is directly

proportional to the size of dose

Not clear, occur by chance.

The probability that effect will occur increases

with doseQ. However, at no time even with

higher doses it is certain that the effect with occur

Associate with

Occur in

Definitely a/w radiation exposure

Irradiated people

Not definitely a/zv radiation exposure and can also

occur in individuals that have not exposed to

radiation above background levels.

Irradiated & normal population both

Examples

Erythema, cataractQ, Alopecia, impaired

fertility, Mvelosuppression etc.

Cancers

Hereditary genetic diseases/effects


Q. 14

Low dose radiation cause:

 A

Lung cancer

 B

AML

 C

Cervical cancer

 D

All

Q. 14

Low dose radiation cause:

 A

Lung cancer

 B

AML

 C

Cervical cancer

 D

All

Ans. D

Explanation:

A i.e. Lung cancer; B i.e. AML; C i.e. Cervical cancer

Intensity modulated RT(IMRT) is most suitable for prostate cancersQ (b/o reduced rectal toxicity) gynaecological cancer eg endometrial cancer (d/t reduced gastrointestinal > genitourinary and bone marrow toxicity) large lung tumors close to esophagus (but issues regarding lung motion, dose calculation accuracy need to be addressed and clinical data is sparse).

–    Reducing rectal toxicity is major dose limiting factor in therapy of prostate cancer, may allow dose escalation and a potential for improved cure rates. Partial sparing of rectal wall seems to be a the major advantage of IMRT, which allow higher than standard doses to be delivered to the prostate. So IMRT with daily image guidance has become routine to treat definitive prostate cancer.

 Radiation induced cancers include thyroid carcinoma, breast carcinoma and sarcomasQ (osteogenic sarcoma> fibrosarcoma> chondrosarcoma> malignant fibrous histiocytoma)- Wolfgang

Secondary malignant tumors after total body irradiation (TBI) include acute myelogenous leukemia (AML)Q, myelodysplastic disease (MDS), post hematopoietic stem cell transplant lymplwproliferative disorder (PTLD), and solid tumors such as oral cavity, pharyngeal, liver, central nervous system, thyroid, bone and soft tissue cancers and melanomas.

–   Risk of radiation induced second malignancy is higher in certain patients including children and young adults, those with known genetic predisposition to cancer (eg Li-Fraumeni, Lynch, Cowden and Gardner’s syndrome), immuno compromized individuals and those with known exposure to other carcinogen (eg chemotherapy tobacco, alcohol etc). Use of highly conformal, intensity modulated radiation therapy designed specifically to deliver lower doses to normal tissues immediately surrounding the tumor, but at the expense of direct, leaked or scattered dose to larger volumes of body (ie large volumes and low doses) tend to be those most associated with radiation carcinogenesis.

– Hodgkin’s lymphoma surviors have risk of breast and lung cancer<2, cervical carcinoma surviors have risk of leukemia and sarcomaQ, and long term surviors of childhood retinoblastoma have risk of sarcomas as second malignancy.

Exposure to ionizing radiation (RT) may cause meningiomas, gliomasQand schwannomasQ and immunosuppression is a risk factor for primary CNS lymphoma (Harrison 3383). There is increased risk of secondary neoplasia in any organQ (eg bone, soft tissues, brain thyroid, salivary glands, eyes, heart, lung, kidney, liver, intestine, gonads etc), depending on the irradiation field after radiation therapy (Harrison 839 table).


Q. 15

Dose of radiation during whole body exposure that leads to haematological syndrome is:

 A

2 Gy

 B

10 Gy

 C

100 Gy

 D

200 Gy

Q. 15

Dose of radiation during whole body exposure that leads to haematological syndrome is:

 A

2 Gy

 B

10 Gy

 C

100 Gy

 D

200 Gy

Ans. A

Explanation:

A i.e. 2 Gy

Total (whole) body irradiation dose > 1 to 2.5 Gy predominatly leads to hematopoietic syndromeQ; dose 5 to 8 Gy predominantly leads to gastrointestinal syndromeQ and doses 20 to 50Gy predominantly leads to cardiovascular syndromeQ.


Q. 16

Radiation hazard is absent in:

 A

MRI

 B

Doppler USG

 C

Digital substraction Angiography

 D

a and b

Q. 16

Radiation hazard is absent in:

 A

MRI

 B

Doppler USG

 C

Digital substraction Angiography

 D

a and b

Ans. D

Explanation:

A i.e. MRI; B i.e. Doppler USG

USG is based on piezoelectric effect Q of lead-zirconate titanate and MRI is based on gyromagnetic property of proton (hydrogen nucleus)Q. Both are associated with no risk of radiation exposureQ.

Nuclear scans (Tc 99 scan) and digital substraction angiography encompass the risk of radiationQ.

Piezoelectric Effect

The ability of certain materials to change their physical dimensions when an electric voltage is applied to them. They are thus able to convert electric voltage to sound energy and vice-versa. This effect is used in ultrasonography to produce the ultrasound beamQ. Piezoelectric crystals used now a days in USG is lead zirconate titanateQ.


Q. 17

Radiation exposure occurs in all except

 A

CT Scan, PET scan

 B

MRI

 C

Fluroscopy

 D

Plain X-Ray

Q. 17

Radiation exposure occurs in all except

 A

CT Scan, PET scan

 B

MRI

 C

Fluroscopy

 D

Plain X-Ray

Ans. B

Explanation:

B i.e. MRI

Radiography use X-rays, which are ionizing radiation.Q

Thermography or thermal imaging is a type of infrared imagine. Thermographic cameras detect radiation in the infrared range of the electromagnetic spectrum (roughly 900-14,000 nanometer or 0.9-14 um)

MRI & USG has no radiation riskQ.


Q. 18

Which one of the following imaging techniques gives maximum radiation exposure to the patient?

 A

Chest X-ray

 B

MRI

 C

CT scan

 D

Bone scan

Q. 18

Which one of the following imaging techniques gives maximum radiation exposure to the patient?

 A

Chest X-ray

 B

MRI

 C

CT scan

 D

Bone scan

Ans. C

Explanation:

C i.e. CT Scan

Patient’s radiation exposure for fluoroscopy & radiography are measured by DAP (dose area product) meter and thermo-luminesent dosimeters (TLDs). The DAP meter measures the product of dose exiting the x-ray tube (D) and the area (A) of x-ray tube, which d/t inverse square law is the same as the product of the dose at the entrance surface of patient and the area of tissue irradiated. Which means as the patient goes away from tube the dose decreases (D/2) in same proportion as the area increases (2A); so DAP remains DXA.

TLD5 measures entrance surface dose (ESD), suitable for single view radiography. ESD can also be calculated based on knowledge of x-ray out put from quality assurance measurement & individual exposure factors.

– The radiation exposure in decreasing order is CT abdomen or pelvis > CT chest > Barium enemaQ > Dynamic cardiac 99rnIcscan > PET head 18FDG > Bone 99mTcscanQ >Barium follow through > Barium meal > IVU (intravenous urogram) > CT head > Barium swallow > Thyroid 99MTc= Kidney 99MTc= Lung perfusion 99MTcscan > X-ray lumbar spine > X-ray thoracic spine = Abdomen = pelvis > X-ray hip > Lung ventilation 133Xescan > X-ray skull > Xray chest PA > Xray limbs & joints (except hip). The MRI and USG have no radiation exposure.

But if we dont specifig & speak broadly the decreasing order can be said as : CT scan > Barium enema > Dynamic cardiac scan > PET > Bone scan > IVU > Xray. However, it is important to note that CT scan head has lesser radiation exposure than IVU.

CT abdomen or pelvis exposes to a dose of 10 mSv which is equivalent to 500 chest Xrays or 4.5 years of background exposure; bone scan exposes to 4 mSv (200 Xray chest or 1.5 yr background exposure); CT head (2 mSv, 100 Xray chest or 10 month be) ; chest Xray (0.02 mSv equivalent to 3 days of be) and Xray limbs (<0.01 mSv, < 0.5 Xray chest or < 1.5 day be).


Q. 19

Post irradiation thyroid tumor is:

 A

Follicular CA

 B

Papillary CA

 C

Lymphoma

 D

Hurthle cell tumor

Q. 19

Post irradiation thyroid tumor is:

 A

Follicular CA

 B

Papillary CA

 C

Lymphoma

 D

Hurthle cell tumor

Ans. B

Explanation:

B i.e. Papillary CA 

Radiation is an etiological agent for papillary carcinoma thyroid & external radiation is used in treatment of anaplastic cancer thyroid.Q


Q. 20

Total skin electron irradiation is used for of

 A

Sezary syndrome

 B

Mycoses fungoides

 C

Psoriasis

 D

Brain metastasis of skin cancer

Q. 20

Total skin electron irradiation is used for of

 A

Sezary syndrome

 B

Mycoses fungoides

 C

Psoriasis

 D

Brain metastasis of skin cancer

Ans. B

Explanation:

B i.e. Mycoses fungoides

Mycosis fungoides is an indolent cutaneous T – cell lymphomaQ with patients often having several years of eczematous or dermatitis skin lesion before the diagnosis is finally established. But the disorder is inevitably fatalQ, although the rate of progression is quite variable.

Mycosis Fungoides and Sezary Syndrome are T-Cell neoplasmQ. Mycosis fungoides (a T Cell malignancy) has skin manifestations like urticatia, erythema, eczema, itching & liard nodules which later on ulcerate containing fungating granulation. Pauterier’s microabscessQ is histological features of mycosis fungoides. TOC is electron beam radiationQ


Q. 21

The source of endogenous radiation is 

 A

Radon

 B

Potassium

 C

Thorium

 D

Uranium

Q. 21

The source of endogenous radiation is 

 A

Radon

 B

Potassium

 C

Thorium

 D

Uranium

Ans. B

Explanation:

Ans. is ‘b’ i.e.. Potassium 

o Radiation is part of man’s environment.


Q. 22

Terrestrial radiation is maximum in-

 A

Karnataka

 B

Orissa

 C

West Bengal

 D

Kerala

Q. 22

Terrestrial radiation is maximum in-

 A

Karnataka

 B

Orissa

 C

West Bengal

 D

Kerala

Ans. D

Explanation:

Ans. is ‘d’ i.e., Kerala 

Terrestrial radiation

Radioactive elements such as thorium, Uranium, radium and an isotop of potassium (K40) arc present in man’s invironment, e.g., soil, rocks, boiling.

o It is estimated that man derives about 50 mrad per year from terrestrial radiation.

Area exists (Kerala in India) where the rock formation containing uranium, it can be as high as 2000, mrad a year.


Q. 23

Effect of radiation above threshold level –

 A

Stochastic effect

 B

Non-Stochastic effect

 C

Lethal effect

 D

Genetic effect

Q. 23

Effect of radiation above threshold level –

 A

Stochastic effect

 B

Non-Stochastic effect

 C

Lethal effect

 D

Genetic effect

Ans. B

Explanation:

Ans. is ‘b’ i.e., Non-Stochastic effect

Types of adverse effects of radiation

o The effects of biological changes caused by radiation can he categorized into :‑

1) Stochastic effects

 A stochastic effect is one where the probability of the effect occurring is governed by the law of chance.

Thus, for radiation induced stochastic effects, the greater the radiation dose received, the greater the

probability of the effect (warring It should be noted that it is the probability of the occurance of effect

which is related to dose not the severity. That means the bigger the dose, the more likely the effect will occur

and the lower the dose, the less likely the effect will occur.

 This has two important consequences in terms of stochastic effects :‑

i) There is no safe dose limit .- All doses of radiation carry some risk and there is no threshold

ii) Severity of the effect is unrelated to the radiation dose recieved, since the probability of the effect occuring is chance related.

iii) Stochastic effects cannot be definitely associated with radiation exposure and occur in both general population as well as in irradiated people.

Two important stochastic effects due to exposure to ionizing radiation are :‑ Radiation induced cancers 

1) Generic effects

2) Non – stochastic (Deterministic or threshold) effects

o A deterministic effect of radiation is one :‑

1) Whose severity increases with radiation dose

ii) For which there is usually a threshold below which the effect will not occur.

ii These effects are definitely associated with radiation exposure and occur only in irradiated people.

iii) Examples of deterministic effects include erythema, cataract, hair loss, impairment of fertility, Myelosuppression.


Q. 24

What is the approximate penetrating ability of alpha particle radiation at tissue level – 

 A

0.05mm

 B

0.1 0 mm

 C

1.50mm

 D

2.00mm

Q. 24

What is the approximate penetrating ability of alpha particle radiation at tissue level – 

 A

0.05mm

 B

0.1 0 mm

 C

1.50mm

 D

2.00mm

Ans. A

Explanation:

 Ans. is ‘a’ i.e., 0.05mm


Q. 25

Unit of one of radiation absorbed is –

 A

Grey

 B

Roengten

 C

Curie

 D

Bequerrel

Q. 25

Unit of one of radiation absorbed is –

 A

Grey

 B

Roengten

 C

Curie

 D

Bequerrel

Ans. A

Explanation:

Ans. is ‘a’ i.e., Gray 

Units of potency

Roentgen and coulomb per kilograme —* Units of exposure. It is the amount to which a person is exposed. o Red and Gray -s Units of absorbed dose. It is the amount which is absorbed per gram of tissue.

o Rem and Sievert -+ Product of the absorbed dose and the modifying factor. Represent the degree of potential:danger to health.


Q. 26

The maximum permissible level of occupational exposure to radiation is…per year –

 A

5 rad

 B

2 rad.

 C

10 rad

 D

50 rad

Q. 26

The maximum permissible level of occupational exposure to radiation is…per year –

 A

5 rad

 B

2 rad.

 C

10 rad

 D

50 rad

Ans. A

Explanation:

Ans. is ‘a’ i.e., 5 Rad

The amount of radiation received from outer space and background radiation has been estimated to be 0.1 rad a year. Apparently, this does not at present constitute a hazard. The additional permissible dose from man made sources should not exceed 5 rad a year.


Q. 27

Testicular tumour most sensitive to radiation is‑

 A

Teratoma

 B

Lymphoma

 C

Mixed germ cell tumor

 D

Seminoma

Q. 27

Testicular tumour most sensitive to radiation is‑

 A

Teratoma

 B

Lymphoma

 C

Mixed germ cell tumor

 D

Seminoma

Ans. D

Explanation:

Ans. is ‘d’ i.e., Seminoma


Q. 28

Radiation exposure during infancy has been linked to which one of the following carcinoma –

 A

Breast

 B

Melanoma

 C

Thyroid

 D

Lung

Q. 28

Radiation exposure during infancy has been linked to which one of the following carcinoma –

 A

Breast

 B

Melanoma

 C

Thyroid

 D

Lung

Ans. C

Explanation:

Ans. is ‘c’ i.e., Thyroid 

“Differentiated thyroid carcinoma particularly papillary variety frequently follows accidental irradiation of thyroid in infancy and childhood” – Bailey

  • Radiation induced cancers
  • Radiation may induce some non-lethal changes in DNA sequences which may cause malignant transformation

 


Q. 29

Most common type of cataract following radiation is:

 A

Posterior subcapsular

 B

Anterior subcapsular

 C

Tear-drop cataract

 D

Diffuse cataract

Q. 29

Most common type of cataract following radiation is:

 A

Posterior subcapsular

 B

Anterior subcapsular

 C

Tear-drop cataract

 D

Diffuse cataract

Ans. A

Explanation:

Ans. Posterior subcapsular


Q. 30

Tumour which can occur following exposure to radiation is:      

March 2009

 A

Osteosarcoma

 B

Osteoblastoma

 C

Ewing’s sarcoma

 D

Osteoclastoma

Q. 30

Tumour which can occur following exposure to radiation is:      

March 2009

 A

Osteosarcoma

 B

Osteoblastoma

 C

Ewing’s sarcoma

 D

Osteoclastoma

Ans. A

Explanation:

Ans. A: Osteosarcoma

Radiation-induced tumors

  • Benign tumors

– Benign exostoses in the treatment field of growing bones

Malignant tumors

Osteosarcoma is most common but undifferentiated fibrosarcoma is nearly as frequent Head and neck are most common sites for induced osteosarcoma

– Chondrosarcoma may also occur

Suspect clinically when pain and swelling occur in irradiated area many years after treatment Radiation changes in bone occur above 3000 rads


Q. 31

Radiation exposure occurs in all of the following except:    

September 2005

 A

CT scan

 B

MRI scan

 C

Fluoroscopy

 D

X-ray

Q. 31

Radiation exposure occurs in all of the following except:    

September 2005

 A

CT scan

 B

MRI scan

 C

Fluoroscopy

 D

X-ray

Ans. B

Explanation:

Ans. B: MRI Scan

MRI is a noninvasive imaging technique that does not involve exposure to ionizing radiation.

MR images of the soft-tissue structures of the body — such as the heart, liver and many other organs — is more likely in some instances to identify and accurately characterize diseases than other imaging methods. This detail makes MRI an invaluable tool in early diagnosis and evaluation of many focal lesions and tumors. MRI has proven valuable in diagnosing a broad range of conditions, including cancer, heart and vascular disease, and muscular and bone abnormalities. MRI enables the discovery of abnormalities that might be obscured by bone with other imaging methods. MRI allows physicians to assess the biliary system noninvasively and without contrast injection. The contrast material used in MRI exams is less likely to produce an allergic reaction than the iodine-based contrast materials used for conventional x-rays and CT scanning. MRI provides a noninvasive alternative to x-ray, angiography and CT for diagnosing problems of the heart and blood vessels.


Q. 32

Which of the following doesn’t produce radiation haz­ard:           

September 2006

 A

MRI

 B

Doppler USG

 C

Both of the above

 D

None of the above

Q. 32

Which of the following doesn’t produce radiation haz­ard:           

September 2006

 A

MRI

 B

Doppler USG

 C

Both of the above

 D

None of the above

Ans. C

Explanation:

Ans. C: Both of the above

MRI is a noninvasive imaging technique that does not involve exposure to ionizing radiation. USG is based on piezoelectric effect and free from radiation.


Q. 33

Which of the following drugs requires a dose adjust­ment in patient during radiotherapy in order to pre­vent radiation toxicity:           

March 2013 (h)

 A

Vincristine

 B

Dactinomycin

 C

Cyclophosphamide

 D

6-Mercaptopurine

Q. 33

Which of the following drugs requires a dose adjust­ment in patient during radiotherapy in order to pre­vent radiation toxicity:           

March 2013 (h)

 A

Vincristine

 B

Dactinomycin

 C

Cyclophosphamide

 D

6-Mercaptopurine

Ans. B

Explanation:

Ans. B i.e. Dactinomycin


Q. 34

Radiation of 5 Gy will kill patients in:

March 2013 (b, c, d, e, f)

 A

1 day

 B

1 week

 C

2-3 weeks

 D

4-6 weeks

Q. 34

Radiation of 5 Gy will kill patients in:

March 2013 (b, c, d, e, f)

 A

1 day

 B

1 week

 C

2-3 weeks

 D

4-6 weeks

Ans. D

Explanation:

Ans. D i.e. 4-6 weeks


Q. 35

How much radiation dose is needed for permanent testicular sterilization in normal male:

March 2013 (f)

 A

0-5 Gy

 B

6-10 Gy

 C

11-15 Gy

 D

16-20 Gy

Q. 35

How much radiation dose is needed for permanent testicular sterilization in normal male:

March 2013 (f)

 A

0-5 Gy

 B

6-10 Gy

 C

11-15 Gy

 D

16-20 Gy

Ans. B

Explanation:

Ans. B i.e. 6-10 Gy


Q. 36

Treatment for post-radiation skin lesion like desquamation:              

March 2013 (e)

 A

Petroleum jellies

 B

Observation alone

 C

Surgery

 D

Antibiotic coverage

Q. 36

Treatment for post-radiation skin lesion like desquamation:              

March 2013 (e)

 A

Petroleum jellies

 B

Observation alone

 C

Surgery

 D

Antibiotic coverage

Ans. B

Explanation:

Ans. B i.e. Observation alone


Q. 37

Radium emits which of the following radiations:

September 2007, 2010

 A

Gamma rays

 B

Alpha rays

 C

Beta rays

 D

All of the above

Q. 37

Radium emits which of the following radiations:

September 2007, 2010

 A

Gamma rays

 B

Alpha rays

 C

Beta rays

 D

All of the above

Ans. D

Explanation:

Ans. D All of the above

Radium was discovered in 1898 by French physicist and Nobel laureate Marie Curie in pitchblende (a uranium andradium­bearing mineral). There is about 1 gram of radium in 7 tons of pitchblende.Elemental radium was isolated by Madam Merry Curie in 1911 Radium is a naturally radioactive, silvery-white metal when freshly cut. It blackens on exposure to air. Purified radium and some radium compounds glow in the dark (luminesce). The radiation emitted by radium can also cause certain materials, called “phosphors” to emit light. Mixtures of radium salts and appropriate phosphors were widely used for clock dials and gauges before the risks of radium exposure were understood. Metallic radium is highly chemically reactive. It forms compounds that are very similar to barium compounds, making separation of the two elements difficult. The various isotopes of radium originate from the radioactive decay of uranium or thorium. Radium-226, the most common isotope, is an alpha emitter, with accompanying gamma radiation, and has a half-life of about 1600 years. Radium-228, is principally a beta emitter and has a half-life of 5.76 years. Radium-224, an alpha emitter, has a half life of 3.66 days. Radium decays to form isotopes of the radioactive gas radon, which is not chemically reactive. Stable lead is the finalproduct of this lengthy radioactive decay series.


Q. 38

Maximum dose of radiation which is considered safe for human in a year is: 

March 2010

 A

5 Rads

 B

10 Rads

 C

15 Rads

 D

20 Rads

Q. 38

Maximum dose of radiation which is considered safe for human in a year is: 

March 2010

 A

5 Rads

 B

10 Rads

 C

15 Rads

 D

20 Rads

Ans. A

Explanation:

Ans. A: 5 Rads


Q. 39

Which of the following tumor is least sensitive to radiation?

 A

Bronchogenic carcinoma

 B

Adenocarcinoma of colon

 C

Malignant melanoma

 D

Osteogenic sarcoma

Q. 39

Which of the following tumor is least sensitive to radiation?

 A

Bronchogenic carcinoma

 B

Adenocarcinoma of colon

 C

Malignant melanoma

 D

Osteogenic sarcoma

Ans. C

Explanation:

Ans. Malignant melanoma


Q. 40

The following is not an ionizing radiation:

 A

MRI

 B

CT

 C

USG

CT

 D

a and c both are correct

Q. 40

The following is not an ionizing radiation:

 A

MRI

 B

CT

 C

USG

CT

 D

a and c both are correct

Ans. D

Explanation:

Ans. a and c both are correct


Q. 41

Radiation mediates its effect by

 A

Denaturation of DNA

 B

Ionization of the molecules

 C

Protein coagulation

 D

Osmolysis of cells

Q. 41

Radiation mediates its effect by

 A

Denaturation of DNA

 B

Ionization of the molecules

 C

Protein coagulation

 D

Osmolysis of cells

Ans. A

Explanation:

Ans. Denaturation of DNA


Q. 42

Least affected by radiation:

 A

OTT

 B

Gonads

 C

Cartilage

 D

Lymphocytes

Q. 42

Least affected by radiation:

 A

OTT

 B

Gonads

 C

Cartilage

 D

Lymphocytes

Ans. C

Explanation:

Ans. Cartilage


Q. 43

Mantle irradiation is used in:

 A

Leukaemia

 B

Hodgkins disease

 C

Chest recondaries from some cancers

 D

Neuroblastoma

Q. 43

Mantle irradiation is used in:

 A

Leukaemia

 B

Hodgkins disease

 C

Chest recondaries from some cancers

 D

Neuroblastoma

Ans. B

Explanation:

Ans. Hodgkins disease


Q. 44

One gray of radiation is equal to:

 A

1 rad

 B

10 rad

 C

100 rad

 D

1000 rad

Q. 44

One gray of radiation is equal to:

 A

1 rad

 B

10 rad

 C

100 rad

 D

1000 rad

Ans. C

Explanation:

Ans. 100 rad


Q. 45

Cell most sensitive to radiation:

 A

Lymphocyte

 B

Neurotrophil

 C

Basophil

 D

Platelets

Q. 45

Cell most sensitive to radiation:

 A

Lymphocyte

 B

Neurotrophil

 C

Basophil

 D

Platelets

Ans. A

Explanation:

Ans. Lymphocyte


Q. 46

Commonly used type of radiation in radiotherapy is:

 A

Alpha rays

 B

Beta rays

 C

Gamma rays

 D

X-rays

Q. 46

Commonly used type of radiation in radiotherapy is:

 A

Alpha rays

 B

Beta rays

 C

Gamma rays

 D

X-rays

Ans. C

Explanation:

Ans. Gamma rays


Q. 47

Radiation protection shields are made up of:

 A

Copper

 B

Silver

 C

Lead

 D

Tin

Q. 47

Radiation protection shields are made up of:

 A

Copper

 B

Silver

 C

Lead

 D

Tin

Ans. C

Explanation:

Ans. Lead


Q. 48

First sign after radiation R„ is:

 A

Erythema

 B

Necrosis

 C

Burns

 D

Deep ulcer

Q. 48

First sign after radiation R„ is:

 A

Erythema

 B

Necrosis

 C

Burns

 D

Deep ulcer

Ans. A

Explanation:

Ans. Erythema


Q. 49

Which tumour responds best to radiation?

 A

Poorly differentiated carcinoma

 B

Anaplastic carcinoma

 C

Well differentiated carcinoma

 D

B and C

Q. 49

Which tumour responds best to radiation?

 A

Poorly differentiated carcinoma

 B

Anaplastic carcinoma

 C

Well differentiated carcinoma

 D

B and C

Ans. B

Explanation:

Ans. Anaplastic carcinoma


Q. 50

Testicular tumour which responds best to radiation is:

 A

Teratoma

 B

Seminoma

 C

Embryonal cell carcinoma

 D

None of the above

Q. 50

Testicular tumour which responds best to radiation is:

 A

Teratoma

 B

Seminoma

 C

Embryonal cell carcinoma

 D

None of the above

Ans. B

Explanation:

Ans. Seminoma


Q. 51

Thickness of lead apron to prevent radiation:

 A

1 mm

 B

3 mm

 C

0.5 mm

 D

7 mm

Q. 51

Thickness of lead apron to prevent radiation:

 A

1 mm

 B

3 mm

 C

0.5 mm

 D

7 mm

Ans. C

Explanation:

Ans. 0.5 mm


Q. 52

Acute radiation sickness is characterised by:

 A

Hematological symptoms

 B

CNS symptoms

 C

Gastrointestinal symptoms

 D

All of the above

Q. 52

Acute radiation sickness is characterised by:

 A

Hematological symptoms

 B

CNS symptoms

 C

Gastrointestinal symptoms

 D

All of the above

Ans. D

Explanation:

Ans. All of the above


Q. 53

Least sensitive structure to radiation is:

 A

Uterus

 B

Cervix

 C

GIT

 D

Vagina

Q. 53

Least sensitive structure to radiation is:

 A

Uterus

 B

Cervix

 C

GIT

 D

Vagina

Ans. D

Explanation:

Ans. Vagina


Q. 54

Intracavitary radiation is given in:

 A

Carcinoma of the cervix

 B

Carcinoma of the lung

 C

Carcinoma of the oesophagus

 D

Carcinoma of the oral cavity

Q. 54

Intracavitary radiation is given in:

 A

Carcinoma of the cervix

 B

Carcinoma of the lung

 C

Carcinoma of the oesophagus

 D

Carcinoma of the oral cavity

Ans. A

Explanation:

Ans. Carcinoma of the cervix


Q. 55

The most common presentation of radiation carditis is:

 A

Pericardial effusion

 B

Atheromatous plaques

 C

Myocardial fibrosis

 D

Pyogenic pericarditis

Q. 55

The most common presentation of radiation carditis is:

 A

Pericardial effusion

 B

Atheromatous plaques

 C

Myocardial fibrosis

 D

Pyogenic pericarditis

Ans. A

Explanation:

Ans. Pericardial effusion


Q. 56

Ionising radiation acts on tissue depending upon:

 A

Linear acceleration energy

 B

Excitation of electron from orbit

 C

Formation of pyrimidine dimers

 D

Thermal injury

Q. 56

Ionising radiation acts on tissue depending upon:

 A

Linear acceleration energy

 B

Excitation of electron from orbit

 C

Formation of pyrimidine dimers

 D

Thermal injury

Ans. B

Explanation:

Ans. Excitation of electron from orbit


Q. 57

All the following are features of radiation except:

 A

Fluorescein

 B

Biological

 C

Photographic

 D

Non penetrating

Q. 57

All the following are features of radiation except:

 A

Fluorescein

 B

Biological

 C

Photographic

 D

Non penetrating

Ans. D

Explanation:

Ans. Non penetrating


Q. 58

The radiation tolerance of whole liver is

 A

15 Gy

 B

30 Gy

 C

40 Gy

 D

45 Gy

Q. 58

The radiation tolerance of whole liver is

 A

15 Gy

 B

30 Gy

 C

40 Gy

 D

45 Gy

Ans. C

Explanation:

Ans. 40 Gy


Q. 59

What dose of radiation therapy is recommended for pain relief in bone metastases?

 A

8 Gy in one fraction

 B

20 Gy in 5 fractions

 C

30 Gy in 10 fractions

 D

Above 70 Gy.

Q. 59

What dose of radiation therapy is recommended for pain relief in bone metastases?

 A

8 Gy in one fraction

 B

20 Gy in 5 fractions

 C

30 Gy in 10 fractions

 D

Above 70 Gy.

Ans. A

Explanation:

Ans. 8 Gy in one fraction


Q. 60

Planned radiation volume is:

 A

Depends on 90% of tumour size

 B

Less than targeted radiation volume

 C

More than targeted radiation volume

 D

Equal to targeted radiation volume

Q. 60

Planned radiation volume is:

 A

Depends on 90% of tumour size

 B

Less than targeted radiation volume

 C

More than targeted radiation volume

 D

Equal to targeted radiation volume

Ans. C

Explanation:

Ans. More than targeted radiation volume


Q. 61

What is the maximum radiation dose to point A for early and advanced Ca cervix?

 A

80-85 and 85-90 gy.

 B

85-90 and 90-95 gy

 C

75-80 and 80-85 gy

 D

70-75 and 75-80 gy

Q. 61

What is the maximum radiation dose to point A for early and advanced Ca cervix?

 A

80-85 and 85-90 gy.

 B

85-90 and 90-95 gy

 C

75-80 and 80-85 gy

 D

70-75 and 75-80 gy

Ans. A

Explanation:

Ans. 80-85 and 85-90 gy


Q. 62

SI unit of dose of radiation absorption?

 A

Red

 B

REM

 C

BPD

 D

FL

Q. 62

SI unit of dose of radiation absorption?

 A

Red

 B

REM

 C

BPD

 D

FL

Ans. C

Explanation:

Ans. BPD


Q. 63

What is the characteristic histological finding of chronic radiation pneumonitis‑

 A

Foam cells in vessel wall

 B

Fibroblasts in lumen

 C

Epithelial cell hyperplasia

 D

Presence of giant cells in vessel wall

Q. 63

What is the characteristic histological finding of chronic radiation pneumonitis‑

 A

Foam cells in vessel wall

 B

Fibroblasts in lumen

 C

Epithelial cell hyperplasia

 D

Presence of giant cells in vessel wall

Ans. A

Explanation:

Ans. is ‘a’ i.e., Foam cells in vessel wall

Radiation-Induced Lung Diseases

  • Radiation pneumonitis is a well-known complication of therapeutic radiation of thoracic tumors (lung, esophageal, breast, mediastinal). It most often involves the lung within the radiation port and occurs in both acute and chronic forms.
  • Acute radiation pneumonitis (lymphocytic alveolitis or hypersensitivity pneumonitis) occurs 1 to 6 months after irradiation in 3% to 44% of patients, depending on dose and age.
  • It is manifest with fever,
  • Dyspnea out of proportion to the volume of lung irradiated, pleural effusion, and infiltrates that usually correspond to an area of previous irradiation.
  • With steroid therapy, these symptoms may resolve completely in some patients, while in others there is progression to chronic radiation pneumonitis (pulmonary fibrosis).

Chronic radiation pneumonitis (pulmonary fibrosis) :

  • The latter is a consequence of the repair of injured endothelial and epithelial cells.
  • It may also occur without antecedent pulmonary symptoms.
  • Morphologic changes are those of diffuse alveolar damage, including severe atypia of hyperplastic type II cells and fibroblasts.
  • Epithelial cell atypia and  foam cells within vessel walls are also characteristic of radiation damage.

Q. 64

Phase of the Cell cycle which is most sensitive to radiation

 A

G,S

 B

GI, G2

 C

G,M

 D

GO, G1DEXA scan

Q. 64

Phase of the Cell cycle which is most sensitive to radiation

 A

G,S

 B

GI, G2

 C

G,M

 D

GO, G1DEXA scan

Ans. C

Explanation:

Ans. c. G2M


Q. 65

Maximum radiation exposure occurs in

 A

Bone scan

 B

X-ray

 C

MRI

 D

CT scan

Q. 65

Maximum radiation exposure occurs in

 A

Bone scan

 B

X-ray

 C

MRI

 D

CT scan

Ans. D

Explanation:

Ans. d. CT scan

Maximum radiation exposure occurs in CT scan among the given options.


Q. 66

Least affected by radiation‑

 A

GIT

 B

Gonads

 C

Cartilage

 D

Lymphocytes

Q. 66

Least affected by radiation‑

 A

GIT

 B

Gonads

 C

Cartilage

 D

Lymphocytes

Ans. C

Explanation:

Ans. is ‘c’ i.e., Cartilage 

Radiosensitivity of important organs in decreasing order

  • Bone marrow > Testes > Ovary > Kidney > Liver > Lung > Heart > GIT (Stomach > Intestine) > Thyroid > Brain & spinal cord (CNS) > Skin + Cartilage > Adult bone > Vagina > Uterus.

Q. 67

Ionizing radiation commonly used for disinfection‑

 A

UV rays

 B

Infrared

 C

X-rays

 D

Gamma rays

Q. 67

Ionizing radiation commonly used for disinfection‑

 A

UV rays

 B

Infrared

 C

X-rays

 D

Gamma rays

Ans. D

Explanation:

Ans. is’d’ i.e., Gamma rays 


Q. 68

Unit of radiation exposure ‑

 A

Gray

 B

Roentgen

 C

Sievert

 D

Red

Q. 68

Unit of radiation exposure ‑

 A

Gray

 B

Roentgen

 C

Sievert

 D

Red

Ans. B

Explanation:

Ans. is ‘b’ i.e., Roentgen 

Units of potency

  • Roentgen and coulomb per kilograme → Units of exposure. It is the amount to which a person is exposed.
  • Red and Gray→ Units of absorbed dose. It is the amount which is absorbed per gram of tissue.
  • Rem and Sievert → Product of the absorbed dose and the modifying factor. Represent the degree of potention danger to health


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