Imaging in inflamm and infection

Question 1

Radionuclide imaging
Positron emission tomography
Magnetic resonance imaging
Optical imaging

Answer 1

Molecular Imaging

Question 2

radiopharmaceutical - gamma rays - pharmaceutical determines where the element go

patient

lead collimator - detect photon
gamma camera - move head to toe
PACS

Answer 2

Radionuclide imaging

Question 3

Which rays travel further? State in order from lowest to highest.

Answer 3

alpha (long wavelength, energy +freq low)
beta
gamma (high penetrance, short wavelength, energy +freq high )

all of above = non-visible

Question 4

x-ray tube

patient

digital image capture

PACS

Answer 4

Radiography

Question 5

Radioactive decay of unstable isotopes

High energy, high frequency, very similar properties to x-rays

Answer 5

Gamma rays/ radiation

Question 6

Properties of an ideal isotope

Answer 6

1/2-life similar to examination length
Gamma, rather than a/b
Energy of g rays = 50-300 keV
Radionuclide = readily available at hospital site
Easily bound to pharmaceutical component
Radiopharmaceutical should be simple to prepare + eliminated in similar half-time to duration of examination

= ideal isotope doesn’t exist

Question 7

Radioisotope - that can be attached to different bits of organ/bones (short-lived 1/2-life = 6.5 hours)
nuclear medicine
gamma

Answer 7

99m Technecium (Tc)

hydroxy-diphosphonate (HDP) bone

dimercapto-succinic acid (DMSA) kidney

hexamethyl-propine amine oxime (HMPAO) brain/ colon (WCS - white cell scan)

macroaggregated albumin lung

Question 8

4 main components of gamma camera

Answer 8

Computer - process info - image on monitor

photomultiplier tubes - many electrons - electronic signal amplified

Scintillator (gamma absorbed - remitted as visible photon/light)

collimeter (lead walls- non-parallel rays abs - parallel pass to scintillator

Question 9

CT version of nuclear medicine
Gamma cameras rotate around area of interest
Routinely used for brain and cardiac studies
Can be applied to any site of interest in other studies e.g. spine in bone scan or in lung scintigraphy

Answer 9

Single photon emission computed tomography (SPECT)

Question 10

Molecular imaging
Uses radionuclides that decay by positron emission – proton –> neutron + positron
Image biologically interesting processes
Absolute quantitation but requires arterial sampling
All scanners now PET CT

Answer 10

Positron emission tomography (PET)

Question 11

PET radionuclides and half lives

Answer 11

18F 110 mins (fluorodeoxy glucose- FDG)
11N 20 min
13C 10 min
15O 2 min

Question 12

Brain
Myocardium
Stomach (arrow)
Liver
Spleen
Colon 
Urinary tract

Answer 12

Physiological FDG uptake

Question 13

Patient breathe in radioactive gas - Scintigraphy

Answer 13

Ventilation

The ventilation scan = how well air moves and blood flows through the lungs.

Perfusion scan = blood supply (radioactive IV) through the lungs.

A ventilation and perfusion scan = detect a pulmonary embolus (blood clot in the lungs). = anti-clotting therapy given if +.

Lower amounts of radioisotope/radionuclidetaken/absorbed = problem/blockage

Question 14

Detect pulmonary embolism
White area - normal vessels
Gray/granular area in vessels/artery - defect

Answer 14

Iodine Contrast