RADIOLOGY MCQ--RADIONUCLIDES

MCQs on radionuclide 

AND 

RADIONUCLIDES ------HALF-LIFE ,MAIN EMMISSIONS   AND ITS USES 

(VERY IMPORATANT FOR EXAM) )

Q1.The ideal agent of choice for ventilation imaging

a._81mKr

b. _99mTc DTPA

c.₁₃₃ Xe

d._99mTc- technegas

Q2.Radionuclide used for ventilation imaging are all except

a. _99mTc DTPA

b.₁₃₃ Xe

c._99mTc- technegas

d._99mTc MAG3

Q3.Which is used for perfusion scintigraphy

a._99mTc  labelled protein microparticles

b._81mKr

c.₁₃₃ Xe

d._99mTc DMSA

ANS  1---a===_81mKr

          2,---d===_99mTc MAG3

          3----a===_99mTc  labelled protein microparticles

 PHYSICAL PROPERTIES OF SOME COMMONLY USED RADIONUCLIDES

			Main emissions (keV)
Radionuclide	Half-life	Main use	Gamma or X	Beta (Emax)
Carbon-11 11C	20 min	p	511	960
Carbon-14 14C	5730 years	n	–	157
Chromium-51 51Cr	27.7 d	n	320	–
Cobalt-57 57Co	270 d	n	122	–
Cobalt-58 58Co	71 d	n	811	475
Fluorine-18 18F	109 min	p	511	634
Gallium-67 67Ga	78 h	g	93, 185, 300	–
Indium-111 111In	67 h	g	171, 245	–
Iodine-123 123I	13.2 h	g	159	–
Iodine-125 125I	60 d	n	27, 31	–
Iodine-131 131I	8 d	t (g)	365	606
Krypton-81m 81mKr	13.5 s	g	191	–
Nitrogen-13 13N	10 min	p	511	1199
Oxygen-15 15O	2 min	p	511	1732
Selenium-75 75Se	120 d	g	136, 265, 401	–
Strontium-89 89Sr	50.7 d	t	–	1492
Technetium-99m 99mTc	6 h	g	140	–
Thallium-201 201Tl	3 d	g	71	–
Xenon-133 133Xe	5.2 d	g	31, 81	346
Yttrium-90 90Y	2.7 d	t	–	2284

Main use: g = gamma camera, n = nonimaging diagnosis, p = PET, t = therapy. Beta (Emax): maximum energy of continuous spectrum; mean energy = approximately one-third of Emax. Main source of decay data1.

Technetium compounds useful for imaging

1.methylene diphosphonate (MDP) for bone imaging

2.hexamethyl  propylene amine oxime (HPMAO) for cerebral imaging

3.dimercaptosuccinic acid (DMSA) and dimercaptoacetyltriglycine (MAG3) for renal studies

4.iminodiacetic acid (HIDA) for biliary studies

5.human serum albumin(HSA) colloidal particles ,0.5micro in size ,which are phagocytosed in  reticuloendothelial studies---imaging of liver,spleen,and bone marrow

6.HSA macroaggregates --15 to 100 micospheres that temporarily block a small fraction of the capillaries in lung perfusion

7.diethylene triamine pentacetic acid (DTPA) aerosol (5 microparticles) in ling ventilation studies

8.autologous red cells ,for cardiac function

9.heat damaged autologous red cells for imaging spleen

10.sestamibi or tetrafosmin for cardiac perfusion studies

 RADIOPHARMACEUTICALS COMMONLY USED FOR A RANGE OF CLINICAL PROBLEMS

Clinical problem		Imaging technique	Radiopharmaceutical	Biological behaviour
Head
Cerebrovascular accident		Cerebral perfusion SPECT	99mTc HMPAO	Uptake proportional to blood flow
Hydrocephalus
CSF rhinorrhoea		Cerebrospinal fluid (CSF) study	111In DTPA (intrathecal)	Marker of CSF flow.
Encephalitis		Blood–brain barrier (BBB) study	99mTc HMPAO	Passage across disrupted BBB
Dementia		Cerebral perfusion SPECT	99mTc HMPAO	Uptake proportional to blood flow
		Cerebral metabolism PET	18F fluorodeoxyglucose	Marker of glucose metabolism
Epilepsy (presurgical localization)		Ictal SPECT	99mTc HMPAO	Uptake proportional to blood flow
		Interictal PET	18F fluorodeoxyglucose	Marker of glucose metabolism
Neck
Thyrotoxicosis			123I sodium iodide	Active uptake (123I and 99mTc) followed by organification (123I)
Thyroid nodule		Thyroid scintigraphy	99m Tc pertechnetate
Ectopic thyroid
Hyperparathyroidism (presurgical localization)		Parathyroid scintigraphy	99mTc MIBI	Differential expression of p-glycoprotein between parathyroid adenoma and thyroid
Dry mouth (connective tissue disease)		Salivary gland study	99mTc pertechnetate	Secretion in saliva
Musculoskeletal system
Tumour
Fracture
Avascular necrosis		Bone scintigraphy	99mTc polyphosphate compounds	Osteoblastic response (+ vascularity on early phases)
Arthropathy
Metabolic bone disease
Painful prosthesis
Osteomyelitis			99mTc polyphosphate	Osteoblastic activity
		Bone scintigraphy + white cell or gallium scintigraphy	99mTc- or 111In-leucocytes	Leucocyte migration
			67Ga gallium citrate	Binds to transferrin and leaks into extravascular space
Lymphoedema		Lymphoscintigraphy	99mTc nanocolloid	Lymphatic uptake and trapping
Cardiovascular system
Chest pain		Myocardial perfusion scan	201Tl (thallous chloride)	K+ analogue indicating perfusion (ischaemic heart disease) (delayed uptake reflects viability)
			99mTc isonitriles	Cationic complexes taken up by myocytes in proportion to blood flow
			99mTc teboroxime	Lipophilic compound which accumulates by diffusion
			99mTc phosphines	Uptake proportional to blood flow
Cardiac failure		Cardiac ventriculography (gated study)	99mTc red blood cells	Blood pool label
		Myocardial viability study	18F fluorodeoxyglucose	Demonstrates shift from metabolism of fatty acids to glucose
Pulmonary embolism		Ventilation/perfusion (V/Q) scan	123I fatty acids
			Perfusion: 99mTc albumin	Pulmonary arteriole blockade
			Macroaggregates
			Ventilation: 99mTc aerosols	Distributes in lungs in proportion to gas regional ventilation
			133Xe gas, 81mKr gas
Congenital heart disease		Quantitative shunt study	99mTc red blood cells	Blood pool label
Pulmonary system
Solitary pulmonary nodule		Tumour imaging	18F fluorodeoxyglucose	Marker of glucose metabolism
Occult lung disease (alveolitis)		Alveolar permeability study	99mTc DPTA aerosol	Passage across alveolar membrane into blood
Gastrointestinal system
Difficulty in swallowing		Oesophageal transit and reflux	99mTc sulphur colloid	Transit of labelled material
Gastrointestinal haemorrhage		GI bleed study	99mTc sulphur colloid	Blood pool label extravasating into bowel
			99mTc labelled red cells
Ectopic gastric mucosa		Meckel's diverticulum scintigraphy	99mTc pertechnetate	Active uptake by ectopic gastric mucosa
Diarrhoea (inflammatory bowel disease)		White cell scintigraphy	99mTc leucocytes	Leucocyte migration
Vomiting (gastroparesis)			99mTc sulphur colloid in egg (solid phase)
		Gastric emptying study		Compartmental localization of labelled material
Dumping			111In DTPA in orange juice (liquid phase)
Focal liver lesion (haemangioma)		Red blood cell study	99mTc labelled red blood cells	Red cell pooling
Cholecystitis
Biliary dyskinesia
		Hepatobiliary study	99mTc iminodiacetic acid derivatives	Uptake by hepatocytes and excretion into bile
Biliary atresia
Bile leak (post-op)
Abdominal sepsis			99mTc or 111In leucocytes	Leucocyte migration
		White cell or gallium scintigraphy
Pyrexia of unknown origin			67Ga gallium citrate	Binds to transferrin and leaks into extravascular space
Ectopic splenic tissue		Splenic scintigraphy	Heat damaged 99mTc labelled red blood cells	Splenic trapping of damaged cells
Urological, adrenal and genitourinary systems
Hypertension (renovascular disease)		Captopril renography	99mTc MAG3	Captopril-induced change in renal transit time and/or function
Renal tract obstruction		Diuresis renography	99mTc DTPA	Glomerular filtration
			99mTc MAG3	Proximal tubular secretion
Renal scarring		Static renal scintigraphy	99mTc DMSA	Glomerular filtration and proximal tubular uptake
Vesicoureteric reflux		Indirect micturating cystogram	99mTc MAG3	Compartmental localization
Adrenal medullary tumour		Adrenal study	123I MIBG	Uptake by noradrenaline transporter
Adrenal cortical tumour		Adrenal study	123I iodocholesterol	Incorporation into hormone metabolism
Cancer
Space occupying lesion in brain (SOL)		Tumour imaging	201Tl (thallous chloride)	K+ analogue indicating perfusion
			18F fluorodeoxyglucose	Marker of glucose metabolism
Thyroid cancer		Whole body iodine scintigram	131I sodium iodide	Uptake by Na/I transporter
Skeletal metastases		Bone scintigraphy	99mTc polyphosphate	Osteoblastic response
Soft tissue mass (sarcoma)		Tumour imaging	201Tl (thallous chloride)	K+ analogue indicating perfusion
			18F fluorodeoxyglucose	Marker of glucose metabolism
Tumour staging
Tumour recurrence		Tumour imaging	18F fluorodeoxyglucose	Tumour glucose metabolism
Tumour response assessment
Insulinoma		Somatostatin receptor study	111In pentetreotide (Octreotide®)	Binds to somatostatin receptors
Carcinoid tumour
Neuroblastoma		MIBG scintigram	123I MIBG	Uptake by noradrenaline transporter
Tumour hypoxia		Hypoxia imaging	18F fluoromisonidazole	Trapped in hypoxic cells
Sentinel node detection		Lymphoscintigraphy	99mTc nanocolloid	Lymphatic uptake and trapping

REF;

1.Adam: Grainger & Allison's Diagnostic Radiology, 5th ed.

2.Farr's physics for medical imaging ,second edition