Lecture 10- Nuclear Medicine Flashcards
(48 cards)
1
Q
nuclear med technologist vs nuclear med advanced associates
A
- tech: bachelor degree; (CNMT) NMTCB or (RT (N)) ARRT accredited
- assoc: midlevel provider for NMAA; masters degree
2
Q
principles of nuclear medicine
A
- physiologic vs structural imaging
- radiopharmaceuticals (radiotracers; energy spectrum; half-life)
3
Q
describe radiotracers
A
radioactive element bound to pharmaceutical
4
Q
describe the energy spectrum
A
- gamma radiation (diagnostic)
- beta/alpha (therapeutic)
5
Q
contraindications for radiopharmaceuticals
A
- allergy
- hx of adverse rxns (rare, but include erythema, edema, fever)
6
Q
isotopes used
A
- 99m TeO4 (most common)
- Xe133 (xenon gas)
- T1201 (thalium)
- I131, I123 (iodine)
- Ga67 (gallium)
- In111 (indium)
7
Q
radiation exposure with nuclear imaging
A
- similar to CXR
- one dose for as many films as needed
- gamma rays emitted in all direction
8
Q
safety components for techs
A
- time
- distance
- shielding
9
Q
Image Acquisition
A
- planar imaging
- SPECT 3D imaging
- Pb (lead) collimator (parallel apertures allows gamma rays) (NOT NEEDED IN NEWER TECH)
- gamma rays hit scintillation crystal
- crystal converts gamma energy to electronic signal (or light)
- cumulative “photo”
10
Q
Image Resolution
A
- ability to distinguish 2 different points as such
- high resolution scans require high res collimator, longer acquisition time
11
Q
sensitivity of images
A
- ability to pick up gama signal
- high sens scans (low res/high sens collimator; shorter acquisition time)
12
Q
artifact sources
A
- affecting apparent distribution (uptake)
- Attenuation: decrease in intensity gamma ray energy
- Scatter: gamma ray changes its path
13
Q
Image processing/manipulations
A
- regions of interest: placed by technologist
- reconstruction: SPECT requires; time required to reconstruct
- manipulations can introduce artifact
14
Q
quality control
A
- cameras: daily flood field testing
- isotope generators
- radiopharmaceuticals
15
Q
image interpretation
A
- read by physician
- hot (increased) or cold (decreased) uptake
16
Q
ordering studies
A
- chronological order is important as isotopes need time to decay
- ex: barium, IV contrast will introduce artifacts
17
Q
how to indicate emergent scan needed?
A
asteriks ( * )
18
Q
common studies
A
- bone scans
- nuclear cardiology (MUGA-ECG gate, exercise MUGA, stress thallium/cardiolite)
- liver/spleen (replaced by US, not common anymore)
- hepatobiliary
- thyroid scan/uptake
- SPECT brain
- V/P or V/Q scans
- VCUG
- renal
- blood flow images (testicular scans, GI bleeds)
19
Q
Bone Scans
A
- Planar or SPECT bone
- used to r/o mets, Paget’s (hot spots), avascular necrosis (e.g. femoral neck; cold)
- isotope: 99mTc MDP IV with imaging 4 hours later; inject L wrist; renal clearance of isotope
- look for symmetry; darker spots are increased upate (thick bone, closer to camera, hypermetabolic)
20
Q
Bone scan film orientation
A
- Right Anterior Left
- Left Posterior Right
- Cephalad is top of film
- Caudal is bottom
21
Q
peds bone scan tips
A
- growth plates darker
- need to give med to block thyroid
- increased uptake in L fibula is most likely a tumor!
22
Q
why bone scan over XR?
A
- Catch stress fx earlier than X ray
- Similar concepts for osteomyelitis
- Function changes earlier detected over Xray structural changes
23
Q
3 phases of a bone scan
A
- 1: blood flow
- 2: blood pool
- 3: bone imaging
24
Q
during which phases are following things visible:
* cellulitis
* acute fx/osteomyelitis/loose prosthetic joints
* chronic fx
A
- cellulitis: phase 1/2
- acute fx/osteomyelitis/loose prosthetic: phase 1/2/3
- chronic fx: none
25
FUO/Infection
Method 1
* Gallium 67 via IV to r/o osteomyelitis
* image at 24, 48, 72 hrs (96) post infusion
Method 2
* 111 labeled WBCs via collecting pt's blood, WBCs isolated, radiolabeled, reinjected
* image at 24, 48, 72 hrs
Method 3
* Ceretec HMPAO for same day imaging
26
Nuclear Cardiology
* echos have replaced but:
MUGA- LV study
* Multi gated acquisition (EKG gated)
* Images Blood Pool; typically 3 view; can view Cardiac wall motion (hypokinesia, akinesia, dyskinesia) and Ejection Fraction (normal is 45-65%)
27
MUGA for Cardiology
* 99mTc PYP labeled RBCs
* 20 mCi
* IV injection of PYP (pyrophosphate) tags to RBCs
* IV injection 20 min later of 99mTcO4- tags to PYP
* Or ultratag kit - 1 bottle with all reagents
28
MUGA interpretation
* Septum appears “cold”
* Anterior
* “Best septal” or LAO (left anterior oblique)
* Used to calculate EF
* L lateral images
* Series of 3 different orientation “cine” pictures
* Additive collection of radioactive particles over and over again to make pictures for movie
29
Abnormal MUGA
* “Flatter” graph
* Decreased EF
* End Diastole and End Systole pictures
* Not much change in size
* This is LAO or best septal view
30
First pass MUGA
* One chance only for Right Ventricle study
* Left heart will “cover” right heart after “first pass” in circulation
* RV: Normal RVEF=45-55% (10% less ish than LV)
* Utilizes butterfly or other IV access (pertechnetate bolus w pt under camera and Blood flow imaged)
31
Exercise MUGA
* Modified bicycle table or other device
* Increase work load (can be done w Echo)
* Normally see LVEF increase with exercise
* Wall motion changes
* (Similar to stress echo)
* Can be done with pharmaceuticals to mimic “stress”- EG persantine
32
Nuclear cardiology stress test
* r/o CAD w SPECT
* Stress Component: Image after exercise protocol completed, LV seen
* Rest Component: Either several hours after exercise (using Thallium- a K+ analog) or first with Cardiolite (pertechnetate derivative); May see RV faintly (Tl)
33
use ot Tl (or TCO4 agents)
* Same views as MUGA
* Anterior
* LAO (see donut w/o “bite”)
* L Lateral
34
Liver/Spleen Scan
* Less common due to US
* 99mTc Sulfur Colloid 4 mCi
* Taken up by macrophage Kuppfer Cells of RES thus, does NOT image hepatocytes!
* Homogenous uptake normal
35
Hepatobiliary Scanning
* r/o biliary obstruction
* Aka HIDA or PIPIDA, DISIDA
* Choletch/mebrofenin: excreted through biliary system
* 99mTc HIDA 4-8 mCi dose: can be adjusted for abnormal LFTs
* should visualize GB by 45-60 min; should visualized SI by 2 hrs
* EF of GB can be calculated after dose of med
36
GI bleed/Meckel's Diverticulum
* Labeled RBCs
* Figure of bleed distal descending colon
37
Gastric Emptying
* Sulfur colloid scrambled eggs for solid
* Sulfur colloid in liquid
* Can follow GI transit time
* Gastroparesis
* E.g. Diabetic
38
Thyroid Scans
* Pertechnetate
* Iodine isotopes
* Thyroid uptake
* HOT vs COLD nodules
* Cold may be malignant or a cyst; US can help
39
SPECT Brain uses
* Cerebrovascular Disease
* Ischemia CVA identified earlier than CT
* Brain death
* Dementia evaluation
* PET brain scans “higher tech”
40
SPECT brain investigations
* DAT (Dementia of Alzheimer’s Type)
* Epilepsy
* Schizophrenia
41
Brain SPECT views
* Transverse (superior to inferior)
* Coronal (ant to post)
* Sagittal (L to R)
42
V/P or V/Q scans
* R/o PE (pulmonary embolism)
* Ventilation phase: Xe 133 gas, Tc99m DTPA aerosol (captures inspiration, equilibrium, washout)
* Perfusion phase: Tc 99m MAA which blocks small capillaries
* Ventilation Perfusion “mismatch” for PE: Ventilation normal --> Perfusion absent area(s)
* If perfusion normal, vent not performed w perfusion first technique
43
V/P COPD findings
* COPD (loner ventilation washout phase; air trapping)
* Area could be infarcted (no ventilation or perfusion)
44
Voiding Cystourethrogram
* TcO4 saline via bladder (Filling phase, Voiding phase)
* Measures bladder volume
* Looks for reflux
45
Testicular Scan uses
* US w doppler has largely replaced
* Acute scrotal pain
* Chronic scrotal pain
* Injury
* Mass
* Torsion
* Note: US usually used
* IV Tc blood flow, pool studies
46
Thyroid Ablation
high dose oral radioactive iodine
47
Nuclear Oncology
* Theranostics- molecular imaging/treatment
* (aka theragnostic) alpha or beta emitters
* Palliative or curative therapy goals
* E.g. mets, but not cure primary site
48
bone met radiotherapy
* palliative
* IV strontium 89
