Radionuclide Scanning

Radionuclide Scanning

Q. 1 The best method of investigation is case of acute cholecystitis is 
 A Ultrasound
 B ERCP 
 C OCG 
 D Radionuclide imaging 
Q. 1 The best method of investigation is case of acute cholecystitis is 
 A Ultrasound
 B ERCP 
 C OCG 
 D Radionuclide imaging 
Ans. D

Explanation:

Radionuclide imaging 


Q. 2

Neuroendocrine tumors (NET) can be best detected by:

 A

PET scan

 B

HRCT scan

 C

MRI

 D

Radionuclide scan

Q. 2

Neuroendocrine tumors (NET) can be best detected by:

 A

PET scan

 B

HRCT scan

 C

MRI

 D

Radionuclide scan

Ans. D

Explanation:

Somatostatin receptor scintigraphy helps in improved visualization of neuroendocrine tumors.

Octreoscan utilizes a somatostatin analogue In 111 labelled diethylenetriamine penta-acetic acid octreotide to visualize somatostatin receptor–positive tumors.

When compared to CT or MRI octreoscan detects additional metastasis in about 1/3rd of patients.

Other nuclear scintigraphy techniques used are:
MIBG: It is absorbed by carcinoid tumor cells.
Iodine labelled MIBG has an overall sensitivity of 55 to 70% in detecting NETs.
Although it is less sensitive than octreoscan, its advantage is that it can be used in patients who are treated by long acting octreotide.
Ref: Jakob J.A., Contreras C.M., Odisio B.C., Gupta S., Abdalla E.K., Yao J.C. (2011). Chapter 23. Neuroendocrine Tumors. In H.M. Kantarjian, R.A. Wolff, C.A. Koller (Eds), The MD Anderson Manual of Medical Oncology, 2e.

Q. 3

A young man presented with hyper parathyroidism. Which of the following radionuclide scan is done for parathyroid adenoma?

 A

Sesta MIBI scan

 B

Iodine-123 scan

 C

99mTc-sulphur colloid

 D

Gallium scan

Q. 3

A young man presented with hyper parathyroidism. Which of the following radionuclide scan is done for parathyroid adenoma?

 A

Sesta MIBI scan

 B

Iodine-123 scan

 C

99mTc-sulphur colloid

 D

Gallium scan

Ans. A

Explanation:

  • The localization ability of Technetium 99m sestamibi scintigraphy is based on its preferential uptake by parathyroid cells, due to their high mitochondrial activity.
  • Delayed images taken 2 to 3 h after injection are sensitive in up to 90% of single adenoma cases, with over 90% specificity. 
  • Sestamibi imaging is also effective in cases of double adenoma. 
  • However, it has significantly reduced accuracy in cases of four-gland hyperplasia.
 
Ref: Singer M.C., Terris D.J. (2012). Chapter 43. Parathyroid Disorders. In A.K. Lalwani (Ed), CURRENT Diagnosis & Treatment in Otolaryngology—Head & Neck Surgery, 3e.

Q. 4

A patient presents with acute renal failure (ARF) and complete anuria. The USG is normal. Which of the following investigation will give best information regarding renal function.

 A

Intravenous Pyelogram

 B

Retrograde Pyelography

 C

Antegrade Pyelography

 D

DTPA scan (Radiorenogram)

Q. 4

A patient presents with acute renal failure (ARF) and complete anuria. The USG is normal. Which of the following investigation will give best information regarding renal function.

 A

Intravenous Pyelogram

 B

Retrograde Pyelography

 C

Antegrade Pyelography

 D

DTPA scan (Radiorenogram)

Ans. D

Explanation:

D i.e. DTPA scan

  • Antegrade pyelography (AP) & retrograde pyelography (RP) are invasive techniques. Percutaneous AP done by puncturing the collecting system & injecting contrast is rarely performed for diagnostic imaging purpose as ultrasound or CT may be used to visualize the ureter even in presence of abnormal renal function. However the indications of AP may be percutaneous nephrostomy (Whitaker test), to obtain renal urine for cyto/bactero-logical examination, to pinpoint obstruction level in dialated urinary system not adequately opacified by IVU/or after failed RP.

Retrograde ureteropyelography (RP) is valuable when (IVU/IVP) is suboptimal owing to poor renal function & in cases where IV contrast administration is contraindicated. Intravenous

urography/pyelography (IVU/IVP) is intravenous administration of iodinated contrast and taking renal x-rays. It is initial technique in evaluation of possible urinary obstruction. For taking additional radiographs rule of 8 (i.e. if no contrast appears in collecting system by 15 min after injection, there is a little reason to obtain next film until 2 hours (=15×8) later) prevent multiple exposure. There has been a significant decline in use of IVU as dominant imaging technique in obstruction d/ t fear of contrast induced nephrotoxicity and d/ t growth of renal sonography & low dose CT. The main draw back of IVU is that it is time consuming.

  • Conventional gray scale sonography is good screening method for detecting subacute and chronic obstruction as demonstrated by pyelocaliectasis however, in acute obstruction pyelocaliectasis is minimal or absent. Another drawback is its inability to realibly distinguish mild hydronephrosis from normal or prominent extrarenal pelvis. Duplex & color Doppler ultrasound have yielded advances in:

– distinguishing mild pyelectasis from prominent central renal blood vessels.

–  detecting high grade acute ureteric obstruction through analysis of ureteral jets (normal ureteral jets i.e. ejection of urine from ureter into urinary bladder are bilaterally symmetrical).

–   estabilishing renal resistive index (RI) as an independent hemodynamic measure of urinary obstruction.

CT scan has emerged as an effective imaging tool in evaluation of acute renal obstruction esp in screening patients with acute flank pain / azotemia who are strongly suspected as having obstruction and in establishing the etiology of ureteral obstruction when other investigations have failed. Non contrast low dose CT is very quick & useful in determining the presence or absence of obstruction and have higher sensitivity for detection of ureteric stones as compared to IVU.

The radionale for CT urography is that high risk patients or patients with hematuria can be fully investigated by a single imaging technique with a high degree of sensitivity & specificity. The major disadvantage is the radiation dose of CTU which is upto 5 times higher than IVU.

  • Radionuclide renography has limited role in evaluation of acute obstruction as it lacks precise anatomical delineation of obstruction as well as ability to define the cause of obstruction. Its major use is in differentiation of a dilated non obstructed system from a partially obstructed system. When IVU demonstrates a dilated collecting system and there is doubt about the presence or absence of obstruction diuresis (frusemide) renography with Tc99 DTPA or MAG-3 will usually help to distinguish obstructive from non-obstructive dilatation & will localize the site of obstruction. The collecting system activity washes out with in 10minutes in non obstructive after diuresis challenge but no or partial response is seen in obstructive cases. Measurement of differential renal function can be made during diuresis renography or as a separate procedure using Tc99 DMSA examinationQ.

MR urography is an ideal technique in pregnancy, where there is contrast allergy, renal failure patients & if radiation dose is an issue. The level of obstruction is always identified however ureteric abnormalities (if < 4mm) are poorly defined & that includes stones.


Q. 5

Investigation of choice for locating Parathyroid gland:

 A

Tc Thallium substraction scan

 B

CAT Scan

 C

USG

 D

Angiography

Q. 5

Investigation of choice for locating Parathyroid gland:

 A

Tc Thallium substraction scan

 B

CAT Scan

 C

USG

 D

Angiography

Ans. A

Explanation:

A i.e. Tc-Thallium Substraction Scan


Q. 6

Functional analysis of kidney is best done by

 A

Radionuclide scanning

 B

IVP

 C

Ultrasound

 D

MRI

Q. 6

Functional analysis of kidney is best done by

 A

Radionuclide scanning

 B

IVP

 C

Ultrasound

 D

MRI

Ans. A

Explanation:

A i.e. Radionuclide scanning


Q. 7

The most sensitive test to detect GI bleeding is ‑

 A

Selective angiography

 B

Radiolabelled, erythrocyte scanning

 C

Fibrinogen studies

 D

Stool for occult blood

Q. 7

The most sensitive test to detect GI bleeding is ‑

 A

Selective angiography

 B

Radiolabelled, erythrocyte scanning

 C

Fibrinogen studies

 D

Stool for occult blood

Ans. B

Explanation:

Ans. is ‘b’ i.e., Radiolabelled, erythrocyte scanning 


Q. 8

Best Diagnosis for Ectopic gastric mucosa of meckels diverticulum –

 A

Fluoroscopy

 B

Occult blood test in stool

 C

Ultrasound abdomen

 D

Radionuclide scan

Q. 8

Best Diagnosis for Ectopic gastric mucosa of meckels diverticulum –

 A

Fluoroscopy

 B

Occult blood test in stool

 C

Ultrasound abdomen

 D

Radionuclide scan

Ans. D

Explanation:

Ans is ‘d’ ie. Radionuclide scan 

“If a Meckels diverticulum is suspected because of repeated gastrointestinal haemorrhage the abdomen can be scanned after the injection of 99Tc-labelled pertechnetate intravenously. This may localise heterotopic gastric mucosa revealing the site of a meckels diverticulum in 90% of cases.” – Bailey & Love


Q. 9

Which test is performed to detect reversible myocardial ischemia?

 A

Coronary angiography

 B

MUGA scan

 C

Thallium scan

 D

Resting echocardiography

Q. 9

Which test is performed to detect reversible myocardial ischemia?

 A

Coronary angiography

 B

MUGA scan

 C

Thallium scan

 D

Resting echocardiography

Ans. C

Explanation:

Answer is C (Thallium scan)

Reversible Myocardial Ischemia can be detected by myocardial perfusion imaging using compounds labeled with thallium- 201 (Thallium Scan).


Q. 10

In radionuclide imaging, the most useful radiophar­maceutical agent for skeletal imaging is:

March 2012

 A

Tc-99m linked to methylene diphosphonate (99m Tc-MDP)

 B

Tc-99 pyrophosphate

 C

Tc-sulphur colloid (99m Tc-Sc)

 D

Gallium 67

Q. 10

In radionuclide imaging, the most useful radiophar­maceutical agent for skeletal imaging is:

March 2012

 A

Tc-99m linked to methylene diphosphonate (99m Tc-MDP)

 B

Tc-99 pyrophosphate

 C

Tc-sulphur colloid (99m Tc-Sc)

 D

Gallium 67

Ans. A

Explanation:

Ans: A i.e. Tc-99m linked to methylene diphosphonate (99m Tc-MDP)

Radiopharmacological agents and uses

  • Tc-99m linked to methylene diphosphonate (99m Tc-MDP) is used in bone imaging
  • Tc-99 pyrophosphate is used for defining hot spots in myocardial infarction/avid infarct imaging
  • 99m Tc-Sc is used in imaging of reticuloendothelial system (liver/ spleen), gastric emptying, GI bleeds
  • Gallium 67 is used for tumours/abscess

Q. 11

Gamma camera is used for:       

September 2007

 A

Measuring the radioactivity

 B

Radionuclide scans

 C

Both of the above

 D

None of the above

Q. 11

Gamma camera is used for:       

September 2007

 A

Measuring the radioactivity

 B

Radionuclide scans

 C

Both of the above

 D

None of the above

Ans. C

Explanation:

Ans. C: Both of the above

A gamma camera/scintillation camera/ Anger camera is a device used to image gamma radiation emitting radioisotopes, a technique known as scintigraphy. The applications of scintigraphy include early drug development and nuclear medical imaging to view and analyse images of the human body or the distribution of medically injected, inhaled, or ingested radionuclides emitting gamma rays. Scintigraphy is the use of gamma cameras to capture emitted radiation from internal radioisotopes to create twodimensional images.

SPECT (single photon emission computed tomography) imaging, as used in nuclear cardiac stress testing, is performed using gamma cameras, usually one, two or three detectors or heads, are slowly rotated around the patient’s torso. Multi­headed gamma cameras can also be used for Positron emission tomography scanning. Gamma camera PET is markedly inferior to PET imaging with a purpose designed PET scanner, as the scintillator crystal has poor sensitivity for the high-energy annihilation photons, and the detector area is significantly smaller. However, given the low cost of a gamma camera and its additional flexibility compared to a dedicated PET scanner, this technique is useful where the expense and resource implications of a PET scanner cannot be justified.


Q. 12

In Radionuclide imaging, the most useful radio-phar­maceutical for skeletal imaging is:   

March 2011

 A

Gallium-67

 B

Technetium-sulphur-colloid

 C

Technetium-99m

 D

Technetium-99m linked to Methylene diphosphonate

Q. 12

In Radionuclide imaging, the most useful radio-phar­maceutical for skeletal imaging is:   

March 2011

 A

Gallium-67

 B

Technetium-sulphur-colloid

 C

Technetium-99m

 D

Technetium-99m linked to Methylene diphosphonate

Ans. D

Explanation:

Ans. D: Technetium-99m linked to Methylene diphosphonate

Applications of Tc-99m includes bone imaging (99m Tc tagged phosphorous compounds)

Scans used for:

  • Hot spot in MI: Technetium scan
  • Pancreatic scanning: Selenium 75
  • Parathyroids: Sestamibi scan
  • Renal GFR estimation: Tc 99DTPA scan
  • Vesicourethral reflex: MAG3 Tc 99 scan
  • Thyroid scan: 1-131

Q. 13

Which of the following is used to detect mucosa in Meckel’s diverticulum:           

March 2011

 A

Technetium-99 scan

 B

Barium meal

 C

CT scan

 D

MRI scan

Q. 13

Which of the following is used to detect mucosa in Meckel’s diverticulum:           

March 2011

 A

Technetium-99 scan

 B

Barium meal

 C

CT scan

 D

MRI scan

Ans. A

Explanation:

Ans. A: Technetium-99 scan

Meckel’s diverticulum can be very difficult to demonstrate by contrast radiology; small bowel enema would be the most accurate investigation

Technetium-99m scanning may be useful in identifying Meckel’s diverticulum as a source of gastrointestinal bleeding


Q. 14

Which of the following is initial investigation of choice for a patient presenting with solitary nodule of thyroid:   

March 2005

 A

Thyroid function test

 B

FNAC

 C

Radionuclide scan

 D

MRI

Q. 14

Which of the following is initial investigation of choice for a patient presenting with solitary nodule of thyroid:   

March 2005

 A

Thyroid function test

 B

FNAC

 C

Radionuclide scan

 D

MRI

Ans. C

Explanation:

Ans. C: Radionuclide scan


Q. 15

Curie is unit for:

 A

Exposure

 B

Absorbed dose

 C

Degree of potential danger to health

 D

Quantity of radionuclide disintegrating per second

Q. 15

Curie is unit for:

 A

Exposure

 B

Absorbed dose

 C

Degree of potential danger to health

 D

Quantity of radionuclide disintegrating per second

Ans. D

Explanation:

Ans. Quantity of radionuclide disintegrating per second


Q. 16

A patient presents with ARF with a normal ultrasound report. The next most useful investigation is:

 A

Renal angiography

 B

Retrograde pyelography

 C

Intravenous pyelography

 D

DTPA scan

Q. 16

A patient presents with ARF with a normal ultrasound report. The next most useful investigation is:

 A

Renal angiography

 B

Retrograde pyelography

 C

Intravenous pyelography

 D

DTPA scan

Ans. D

Explanation:

Ans. DTPA scan


Q. 17

Investigation of choice in parathyroid pathology is:

 A

CT scan

 B

Gallium scan

 C

Thallium scan

 D

Technetium-thallium subtraction scan

Q. 17

Investigation of choice in parathyroid pathology is:

 A

CT scan

 B

Gallium scan

 C

Thallium scan

 D

Technetium-thallium subtraction scan

Ans. D

Explanation:

Ans. Technetium-thallium subtraction scan


Q. 18

In radionuclide imaging the most useful radio pharmaceutical for skeletal imaging is:

 A

Gallium 67 (67Ga)

 B

Technetium-sulphur-colloid (99mTc-Sc)

 C

Technetium-99m (99mTc)

 D

Technetium-99m linked to Methylene dis-phos-phonate (99mTc-MDP)

Q. 18

In radionuclide imaging the most useful radio pharmaceutical for skeletal imaging is:

 A

Gallium 67 (67Ga)

 B

Technetium-sulphur-colloid (99mTc-Sc)

 C

Technetium-99m (99mTc)

 D

Technetium-99m linked to Methylene dis-phos-phonate (99mTc-MDP)

Ans. D

Explanation:

Ans. Technetium-99m linked to Methylene dis-phos-phonate (99mTc-MDP)


Q. 19

Which radionuclide is best suited for measurement of GFR?

 A

DTPA

 B

DMSA

 C

Orthoiodohippurate

 D

EDTA

Q. 19

Which radionuclide is best suited for measurement of GFR?

 A

DTPA

 B

DMSA

 C

Orthoiodohippurate

 D

EDTA

Ans. A

Explanation:

Ans. DTPA



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