Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Nuclear Med > week 5-6 > Flashcards

week 5-6 Flashcards

1
Q

advantage of SPECT

A
  • improved image contrast
  • absolute 3D localisation of tracer distribution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

maximum COR error

A

<0.5 pixels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

application of NM cardiac imaging

A
  • MUGA
  • cardiac amyloidosis (PYP imaging)
  • SPECT myocardial perfusion imaging
  • PET/CT cardiac imaging (MPI and viability imaging)
  • cardiac sarcoidosis (18F-FDG PET/CT)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is NM cardiac imaging

A
  • non invasive evaluation of cardiac physiology and function
  • selective detection and functional consequences of numerous cardiac abnormalities
  • provides complementary information to anatomic imaging techniques
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

radionuclide imaging procedures are designed to assess

A
  • myocardial perfusion and viability
  • regional and global ventricular function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is ECG G-SPECT

A
  • semi quantitative evaluation of coronary perfusion and LV function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

semiconductors detectors possess superior

A
  • energy resolution
  • better scatter rejection
  • can be made in a compact
  • and rugged package
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

with superior characteristics, semiconductor detectors ensure

A
  • improved image contrast
  • improved multi-isotope imaging
  • faster scanning/ lower dose scans
  • more flexibility in scanner design
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is SPECT/CT

A
  • hybrid imaging technique that allows the direct fusion of morphologic information and functional information
  • lesions visualised by functional imaging can be correlated with anatomic structures
  • more anatomic information = increase sensitivity and specificity or scintigraphic findings
  • add true diagnostic information derived from CT imaging
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

advantages of SPECT/CT

A
  • improved attenuation correction, resulting form the more accurate and precise attenuation map with CT
  • add value to SPECT studies with superior quantification of radiotracer uptake
  • ability to perform complementary diagnostic studies in the same setting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

challenges associated with SPECT/CT

A
  • increased cost of the equipment and room preparation
  • patient motion, CT metal artifacts
  • total radiation burden to patient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

PET imaging is useful in

A
  • measuring blood flow into tissues and tumours
  • imaging and measuring receptors
  • imaging of enzyme and cellular functions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

isotopes elements used for PET

A
  • carbon 11
  • oxygen 15
  • fluorine 18
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

why do PET scan

A
  • higher sensitivity
  • uniform high resolution
  • superior attenuation correction
  • superior quantification
  • high clinical sensitivity and specificity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

PET decays and emits

A

positron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

in PET, protons decay to

A

a neutron, positron and neutrino

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

daughter isotope in PET has how many more/less atomic number than parent

A

one less

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

in PET, what happens to the positrons emitted

A

annihilate nearby electron, resulting in 2 gamma rays of 511KeV travelling at 180deg to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is “coincident”

A

two detection events unambiguously occuring within a certain time window

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

resulting image of a PET scan shows

A
  • tracer distribution throughout the body of the subject
  • 3D images of the localisation of the radioisotope can be reconstructed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

design of the detector block in a PET/CT scanner machine

A
  • a block of LSO crystals is coupled to 4 small PMT with light sensitive adhesive
  • each block is magnetically shielded by a metal casing
  • grooves between adjacent crystal blocks are filled with light reflecting compound
  • 12 blocks arranged in a 3x4 format constitute a bucket
  • 12 buckets (144 blocks) in the whole PET ring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

advantages of electronic collimation

A
  • improved sensitivity
  • improved uniformity

of the point source response function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

3 types of coincidence events

A
  • true
  • scattered
  • random
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is true coincidence

A
  • when both photos from an annihilation events are detected by detectors in coincidence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is scattered coincidence

A

at least one of the detected photons has undergone at least one compton scattering event prior to detection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is random coincidence

A

two photos not arising from the same annihilation event are incident on the detectors within the same coincidence time window of the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what are the energy of the different coincidence

A

T = 511kev
S = <511 kev
R = 511 kev
attenuated / undetected = <511kev

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is scatter map used for

A

correct the PET scan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

problem associated with attenuation in PET scan

A
  • photons are stopped in the patient body reaching the PET detector
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

consequence of attenuation in PET scan

A
  • reduces appearance of deep lesions
  • reduces quantitative accuracy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

solution to attenuation in PET scan

A
  • perform attenuation correction with scan of patient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

problems with random coincidence

A
  • randoms equal and may exceed true events
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

consequence of random events

A
  • reduced contrast
  • reduced accuracy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

solution to random events

A
  • measure random events
  • reduce randoms by decreasing coincidence time window
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

key benefits of PET/CT

A
  • combine functional and anatomical imaging for highest accuracy coregistration and fusion
  • PET and CT components can be operated independently
  • short duration, low noise CT-based attenuation correction and scatter correction
  • faster overall scanning time
  • fully quantitative, whole-body images for SUV calculation
  • applications in improved disease localisation, biopsy guidance, therapy monitoring, and radiation therapy planning
36
Q

imaging sequence for a PET/CT

A
  • topogram or scout for positioning
  • spiral CT scan and generation of ACF
  • PET scan over the same axial range as CT + reconstruction of CT images simultaneously
  • attenuation correction of PET data
  • reconstruction of attenuation corrected PET data
  • display of final fused images
37
Q

why PET/MR

A
  • high soft-tissue contrast
  • advanced MRI techniques such as MR spectroscopy allows in vivo identification of specific chemical compounds and provides insight into physiological changes in tissue of interest
  • combination of PET and MRI increases the diagnostic accuracy but PET and MRI data fused in retrospect often result in misalignment and motion artefacts
  • simultaneous acquisition can be achieved; risk of misalignment due to patient movement will be greatly reduced with shorter examination time
38
Q

advantages of PET/MR

A
  • reduce exposure to ioninsing radiation
  • similar to image quality and quantitative data achieved using PET/CT
  • higher quantitative lesion contrast due to decrease in background SUVs
  • volumetric axial sequences gives good resolution and better registration
39
Q

steps involved in reconstruction of SPECT image

A
  1. acquisition
  2. correction
  3. QC
  4. reconstruction (filtered back projection)
  5. attenuation correction
  6. reconstruction (transverse –> coronal and sagittal)
40
Q

centre of rotation calibration recommendation

A
  • point source placed at the centre of the FOV
  • point source placed off centre relative to the AOR
  • line source
  • byte or word mode of acquisition
  • separate COR calibration for 64x64 and 128x128 matrix sizes
41
Q

radionuclide imaging procedures are designed to assess

A
  • myocardial perfusion and viability
  • regional and global ventricular function
42
Q

regional wall motion abnormalities are classified into

A
  • hypokinetic - diminished wall motion
  • akinetic - absent wall motion
  • dyskinetic - particular segments moves paradoxically outward rather than contracting inward during systole
43
Q

what is the difference between cardiac SPECT and conventional SPECT

A
  • use of CZT, which have a higher sensitivity for the detection of photons
  • advanced software solutions, such as iterative reconstruction, resolution recovery and noise reduction
  • reduction in the administered activity while maintaining image quality
44
Q

2 dedicated cardiac SPECT

A
  • CZT with multiple single-hole detectors
  • upright CZT camera with sweeping parallel-hole collimators
45
Q

difference between administered dose in conventional and dedicated cardiac SPECT

A

C = 8-12mCi
D = 4-6mCi

46
Q

acquisition duration for conventional and dedicated SPECT

A

C = 15-25mins
D = 2-8 mins

47
Q

what does MUGA do

A
  • qualitative and quantitative of LV function
  • assess cardiac chamber morphology
  • evaluate global and regional measures of ventricular function
48
Q

indications for a MUGA scan

A
  • cardio-oncology
  • vavular heart disease
  • cardiomyopathy
49
Q

what is the radiopharmaceutical used for MUGA

A
  • Tc99m labelled RBC
  • reduction of Tc99m pertechnetate is required to bind firmly to haemoglobin
50
Q

radioactivity for MUGA radiotracer

A

20mCi

51
Q

RBC labelling techniques

A
  • in vivo
  • in vitro
  • mixed in vivo/ in vitro
52
Q

indications for PYP

A
  • individuals with heart failure and unexplained increase in LV wall thickness
  • individual over the age of 60 years with unexplained heart failure with preserved ejection fraction
  • individuals with unexplained neuropathy, bilateral CTS or atrial arrhythmias in the absence of usual risk factors, and S&S or heart failure
  • diagnosis of cardiac ATTR in individuals with CMR or echocardiography consistent with cardiac amyloidosis
  • patients with suspected cardiac ATTR amyloidosis and contraindications to CMR such as renal insufficiency or any implantable cardiac device
53
Q

additional imaging to PYP

A
  • SPECT
  • whole body planar imaging
54
Q

limitations of PYP

A
  • high affinity for areas of bones with altered osteogensis, damaged myocardial cells and RBC, specifically visualised in areas of blood pooling
  • uptake by overlying breast tissue, degenerative bone disease, parenchymal lung processes such as consolidation and atelectasis, and attenuation from overlying devices on the chest wall can all result in false-positive when using planar imaging alone
55
Q

indications for SPECT MPI

A
  • ischemic assessment
  • risk stratification in stable CAD
  • post-acute MI eval
  • eval after revascularisation procedures
  • pre-operative assessment
  • viability assessment to detect hypoxic yet viable myocardium that would benefit from revascularisation
56
Q

pharmacologic stress agents for stress testing in SPECT MPI

A
  • dipridamole
  • adenosine
  • regadenoson
  • dobutamine
57
Q

advantages of SPECT MPI

A
  • lower cost
  • less complex
  • better accessibility and availability
58
Q

advantages of PET/CT MPI

A
  • shorter imaging protocol
  • lower radiation exposure
  • ability quantify absolute myocardial perfusion
59
Q

radiotracers for PET/CT MPI

A

13NH3
82Rb
15O water

60
Q

purpose of myocardial viability imaging

A
  • identify chronically dysfunctional myocardium in CAD that may benefit from revascularisation
  • performed as a combination of MPI and FGD
61
Q

FGD PET/CT is a useful imaging method for

A
  • diagnosis and monitoring treatment response in patients with cardiac sacroidosis
  • detection of early disease, determining active vs chronic disease
  • combined whole-body PET examination performed for the detection of systemic sarcoidosis
62
Q

imaging protocol for sarcoidosis

A
  • FDG PET/CT performed with resting MPI, followed by whole body imaging to assess for extra-cardiac disease
  • high fat and low carbs diet followed by prolonged fasting of about 12-18 hours has been recommended to suppress normal metabolic uptake of FDG in the myocardium so that FDG accumulation due to sarcoidosis can be detected
63
Q

what is the gastric emptying scan for

A
  • evaluate the rate of gastric emptying
  • involves eating a light meal that contains a small amount of radioactive material
  • goal of scan is to identify patients with gastric motility problems who will benefit from either prokinetic drugs or other treatments to alleviate their symptoms
  • amount of radioactivity in stomach is measured at various time points, to determine the volume of a meal remaining in stomach and thus determine the rate of GE
64
Q

indications of GE scan

A
  • exclude gastroparesis as a cause for persistent nausea and vomiting
  • confirm or exclude delayed gastric emptying in diabetic patients w poor glycaemic control
65
Q

contraindications of GE scan

A
  • allergies to the recommended meal
  • hyperglycemia in diabetic patients
66
Q

advantages of GE scintigraphy

A
  • non invasive
  • quantification of the data
  • low radiation burden permitting repetitive testing
  • ability to analyse fundal, antral, and overall gastric motility
67
Q

patient position during GE imaging

A

erect, hands resting on top of detectors

68
Q

how many times is GE scan imaged and at what time points

A

4 times
- 0h
- 1h
- 2h
- 4h

69
Q

what is considered normal GE

A
  • 30 to 60% gastric retention at 2 hours and
  • 0 to 10% at 4 hours
70
Q

what is considered delayed GE

A
  • more than 60% gastric retention at 2 hours or
  • more than 10% at 4 hours
71
Q

what is rapid GE

A

less than 30% gastric retention at 1h

72
Q

what does 0-2hrs see in GE

A

early phase - reflect primarily fundal function

73
Q

what does 2-4 hours see in GE

A

late phase - reflect how antral process and push food into the duodenum

74
Q

advantages of hybrid imaging

A
  • increased diagnostic accuracy
  • better treatment planning
  • reduced need for additional tests
  • earlier detection of disease
  • more personalised treatment
  • improved guidance for interventions
75
Q

contraindication for a GE scan

A

pregnancy

76
Q

PMTs have very large

A

electronic gains (10^6) with relatively low noise

77
Q

PMTs have conversion efficiency of

A

20% - affects both energy resolution and intrinsic spatial resolution

78
Q

PMTs are affected by

A

environmental changes such as
- temperature
- humidity
- magnetic fields and
- their age

79
Q

examples of improved replacements for conventional PMTs

A
  • position sensitive PMT (PSPMT)
  • avalanche photodiode (APD)
  • silicon PMT
80
Q

radiotracer used in MUGA

A

Tc-99m labelled RBC

81
Q

radiotracer used in SPECT MPI

A

Tc-99m
Thallium-201

82
Q

radiotracer used in PET/CT MPI

A

ammonia
rhubidium
water

83
Q

radiotracer used in PET/CT viability imaging

A

18F-FDG

84
Q

radiotracer used in PYP imaging

A

Tc99m-PYP

85
Q

radiotracer used for cardiac sarcoidosis imaging

A

18F-FDG PET/CT

Nuclear Med (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions