Q-11. Which of following is the most radiosensitive phase of cell cycle?
a) G1
b) S
c) G2
d) M
Answer: M phase (?)
Explanation:
Cells are least radio-sensitive when in the S phase, then the G1 phase, then the G2 phase, and most sensitive in the M phase of the cell cycle. (Wikipedia)
Cells being most radiosensitive in the G 2-M phase, less sensitive in the G-1 phase, and least sensitive during the latter part of the S phase.
Q-12. X rays are produced when
a) Electron beam strikes the nucleus of the atom
b) Electron beam strikes the anode
c) Electron beam reacts with the electromagnetic field d) Electron beam strikes the cathode
Answer: Electron beam strikes the anode
Explanation:
An X-Ray tube in its simplest form consists of an anode and cathode mounted inside an evacuated glass tube. The cathode generally consists of a small coil of wire, called a filament, mounted in a focusing cup. The anode target is generally made from tungsten separated from the filament by a small gap, although molybdenum and rhodium targets are used in Mammography. Electrons are boiled off the filament by applying an electric current so that it becomes white hot – the process is called Thermionic Emission. A high voltage (HV) of up to 100 kV or more is then applied and the electrons are attracted across the gap to collide with the anode at high energies, to produce X-rays. The focusing cup can be used to form the electrons into a narrow beam and hence only strike a small spot on the anode target. X-rays are produced in all directions from this focal spot, but beam restriction devices (e.g. collimators; not shown in the figure) are used to allow only a primary beam to escape the source and irradiate the patient.
Q-13. Which of the following imaging modalities is most sensitive for evaluation of extra adrenal pheochromocytoma?
a) USG
b) CT
c) MRI
d) MIGB Scan
Answer: MRI
Explanation:
CT or MRI of the adrenal is usually successful in identifying intra-adrenal lesions.
MRI or PET scanning with 18 F-dopa is useful in identifying extra-adrenal tumor. MIBG is less useful than MRI or PET.
MRI is the most sensitive modality for identification of pheochromocytomas, and is particularly useful in cases of extra-adrenal location. The overall sensitivity is said to be 98%.
MIBG: As many tumors demonstrate uptake with MIBG, it is not specific for phaeochromocytoma. Overall sensitivity is approximately 81%.
PET: 18F Dopa PET is thought to be highly sensitive according to initial results.
Q-14. High resolution CT of the lung is a specialized CT technique for greater detail of lung parenchyma and it utilizes:
a) Special lung filters
b) Thick collimation
c) Bone algorithm for image reconstruction
d) Large field of view
Answer: Bone algorithm for image reconstruction Explanation:
The high-spatial-frequency (bone) reconstruction algorithm has been shown to be superior to the standard algorithm in the assessment of thin-section images of the lung parenchyma and mediastinum.
Q-15. A dense persistent nephrogram may be seen in all of following except:
a) Acute ureteral obstruction
b) Systemic hypertension
c) Severe hydro-nephrosis
d) Dehydration
Answer: Systemic hypertension (?)
Explanation:
Increasingly dense unilateral nephrogram:
Obstruction
Renal vein thrombosis
Renal artery stenosis
Persistent bilateral nephrogram:
Hypotension/shock
ATN
Acute Glomerulo-nephritis
Q-16. A young man with TB presents with massive recurrent hemoptysis. For angiographic treatment which vascular structure should be evaluated first?
a) Pulmonary artery
b) Bronchial artery
c) Pulmonary Vein
d) Superior vena cava
Answer: Bronchial artery
Explanation:
Most common vessel responsible for the hemoptysis in TB, even in bronchitis, bronchogenic carcinoma is the bronchial artery.
Bronchial artery angiography with embolization has become a mainstay in the treatment of hemoptysis. Major complications are rare and immediate clinical success defined as cessation of hemorrhage ranges in most series from 85% to 100%, although recurrence of hemorrhage ranges from 10% to 33%. Bronchial artery embolization offers a minimally invasive procedure for even the most compromised patient serving as first-line treatment for hemorrhage as well as providing a bridge to more definitive medical or surgical intervention focused upon the etiology of the hemorrhage.
Q-17. A 22 years old man presents with a solitary 2 cm space occupying lesion of mixed echogenecity in the right lobe of the liver on USG. The rest of the liver is normal. Which of the following test should be done next?
a) Ultrasound guided biopsy of the lesion
b) Hepatic scintigraphy
c) Hepatic angiography
d) Contrast enhanced CT scan of the liver
Answer: Hepatic scintigraphy
Explanation:
MRI as the diagnostic test of choice for hepatic hemangioma at most centers. Nuclear medicine studies may be used to confirm the diagnosis when a probable hemangioma is detected on ultra-sonography. Nuclear medicine studies may also help to clarify the nature of a lesion when the diagnosis is equivocal on CT or MRI.
Percutaneous biopsy of a hepatic hemangioma carries an increased risk of hemorrhage. Liver biopsy is contraindicated in most circumstances where a hemangioma is high in the differential diagnosis of a hepatic mass.
Hepatic angiography: The diagnostic accuracy of noninvasive tests has obviated the need for hepatic arteriography in most cases.
Q-18. The most likely diagnosis in a new born who has radio- opaque shadow with an air -fluid level in the chest along in the chest along with hemi-vertebra of the 6th thoracic vertebra on plain x-ray is-
a) Congenital diaphragmatic hernia
b) Esophageal duplication cyst
c) Bronchogenic cyst
d) Staphylococcal pneumonia
Answer: Bronchogenic cyst
Explanation:
Bronchogenic cysts are considered as foregut malformations and like the intestinal duplications; they are thought to be derived from an anomalous division of the embryonic foregut.
Bronchogenic cysts are rare congenital anomalies that result from abnormal budding or branching of tracheo-bronchial tree.
The other broncho-pulmonary foregut malformations include tracheo-esophageal fistula, esophageal diverticulum, esophageal cyst and lung sequestration.
Vertebral abnormalities (hemi-vertebrae) are often associated with bronchogenic cyst of mediastinal origin.
Although bronchogenic cysts are usually fluid filled, occasionally a communication may develop following infection or intervention, resulting in air-filled cystic structure or an air-fluid level
Q-19. The most recent advance in non-invasive cardiac output monitoring is use of:
a) PA catheter
b) Thermo-dilution technique
c) Echocardiography
d) Electrical impedance cardio-graph technology
Answer: Electrical impedance cardio-graph technology Explanation:
The monitoring of the cardiac output (CO) and other hemodynamic parameters, traditionally performed with the thermo-dilution method via a pulmonary artery catheter (PAC), is now increasingly done with the aid of less invasive and much easier to use devices.
Direct Fick- Very Invasive
PA catheter- Very Invasive
Thermo-dilution technique- Invasive
Electrical impedance cardio-graph technology- Completely Noninvasive and also ideal for children
Q-20. In a patient presenting with hemoptysis and purulent cough, the x-ray was found to be normal. The investigation done to aid in diagnosis is.
a) CT guided biopsy
b) High resolutions CT scan
c) Bronchoscopy
d) MRI
Answer: Bronchoscopy
Explanation:
Fibre-optic Bronchoscopy enables direct visualization and is required where there are risk factors for cancer despite normal CXR, or where diagnosis remains open, particularly in instances of recurrent hemoptysis.