nuclear medicine AT4 revision Flashcards
(86 cards)
1
Q
why is correct patient positioning crucial
A
- enhances imaging quality
- improves diagnostic accuracy
- minimizes patient discomfort +motion
- optimizes radiation safety
- enhances workflow efficiency
2
Q
general positioning principles
A
- patient comfort
- patient co-operation
- anatomical landmarks
- immobilization techniques
3
Q
body habitus
A
sthenic - average mesomorphic
asthenic - very slender ectomorphic
hyposthenic - intermediate between sthenic and asthenic
hypersthenic - larger build endomorphic
4
Q
bony landmarks for positioning
A
- tip of the nose
- symphysis menti
- sternal notch
- xiphoid process
- Lt, Rt costal margin
- Lt, Rt iliac crest
- Lt, Rt greater trochanter of the femur
5
Q
patient positioning
A
- supine
- prone
- head first
- feet first
- craniocaudal
- caudocranial
- decubitus (side)
- erect (standing)
6
Q
core imaging techniques
A
- static imaging
- dynamic imaging
- whole body imaging
SPECT imaging
7
Q
static imaging
A
single images
8
Q
dynamic imaging
A
process
9
Q
whole body imaging
A
spread
10
Q
SPECT imaging
A
3D
11
Q
digital image characteristics
A
matrix size
12
Q
functions of bone
A
- support - provides framework for support
- movement - bones y tendons
- protection - protect vital organs
- blood cell formation - hematopoiesis occur in the bone marrow
- mineral storage - Calcium, phosphates to be release into blood stream when required
13
Q
mineral homeostasis
A
calcium and phosphorous - strength and rigidity, stored inside, required systemically for normal muscle and nerve function
fluoride - increases strength of bones, replaces part of hydroxyapatite crystal
magnesium - required for over 300 biochemical reactions 50% stored in bones, other stored in tissue and organs
manganese - required for various enzymes
14
Q
chemical composition of bone
A
inorganic components and organic components
15
Q
inorganic components
A
hydroxyapatites are mineral salts that form tiny crystals that surround the collagen fibers in the extracellular matrix
main mineral salt is calcium phosphate forming hydroxyapatite with calcium hydroxide
16
Q
organic components
A
the cells - osteoblasts, osteoclasts, osteocytes, osteoids
17
Q
Osteoid
A
is made of collagen fibers, glycoproteins and polysaccharides making the bone structure flexible and tensile strength.
18
Q
bone composition
A
inorganic salts (69%) - amorphous calcium phosphate (ACP)
to HA made from Ca, P, OH
organic matrix (22%) - ground substance (10%) and collagen fibers (90%)
and water 9%
19
Q
organic matrix four cell types
A
- osteogenic cells
- osteoblasts
- osteoclasts
- osteocytes
20
Q
osteogenic cells
A
stem cells that form most of the connective tissue in the body, only bone cell undergoes mitosis these cells develop into osteoblasts
21
Q
osteoblasts
A
build/form bone, synthesis soft matter if the matrix is hardened by mineral deposition, stress on the bone will stimulate more osteoblasts, they secrete osteocalcin
22
Q
osteocytes
A
are former osteoblasts that have been trapped in the matrix they formed. some reabsorb matrix others deposit matrix, act as stress sensors
23
Q
osteoclasts
A
dissolve bone, found on the bone surface, formed by the fusion of several stem cells, plays a role in bone remodeling
24
Q
blood supply
A
arterial vessels are accompanied by nerves into the bone. the vessels run longitudinally through the central haversian canals and perforating canals
25
blood supply in long bones components
1. periosteal
2. metaphyseal
3. epiphyseal
4. nutrient
26
hormones are required for bone growth
in children growth hormones are released by the anterior pituitary gland and is responsible for the epiphyseal plate activity, this is regulated by thyroid gland hormones.
at puberty estrogen and testosterone are released to promote growth spurts
27
minerals and vitamins required for bone growth or remodeling
rich diet in protein, vitamins A, C and D, minerals required - calcium, phosphorous, manganese and magnesium
28
bone remodeling
- continuous replacement of old to new bone
- the rate of bone resorption by osteoclasts is matched by the rate of bone deposition by osteoblasts
- renewal rate of compact bone (4% yr) and spongy bone (20% yr)
- osteoblasts lay down the osteoid , ACP salts precipitate on the collogen fibers, these salts grow and through osteoclastic resorption and the + or - of other atoms convert to crystalline HA
29
factures
the healing process follows a series of progressive steps
1- a fracture hematoma forms
2 - internal and external callus
3 - cartilage of the callus is replaced by trabecular bone
4 - remodeling begins
30
radiopharmaceuticals used in bone imaging
the imaging agents used in skeletal scintigraphy exploit the bone remodeling process
- 99m-Tc MDP (methylene diphosphate)
- 99m-Tc HDP (hydroxy methylene diphosphate)
31
MDP and HDP mechanism of localisation
the disphosphates interact with the Ca2+ ions in the inorganic matrix, known as chemisorption.
the immature amorphous calcium phosphate (ACP) salts chemical configuration binds well to the diphosphonate ligands, configurations of the crystal changes from ACP to HA when bone matures.
32
how are bony lesions detected
the difference between HA and ACP uptake provides detection in areas of increased osteoblastic activity
33
the tracers
the uptake in the bone depends on these factors
- regional blood flow
- osteoblastic activity
- extraction efficiency of the RP
typical administered activity is 740MBq for &% Kg make
34
uptake and pharmacology
- tracer is injected I.V
- rapid distribution in extracellular matrix and uptake of bones
- accumulation dependent on regional blood flow and osteoblastic activity
- binding occurs by chemisorption in the HA
- decreased activity can be seen in areas of reduced blood flow or infraction. no uptake or cold spots may be seen in areas of destructions like metastases
35
bone tumors
are abnormal growths or masses of cells in bone tissue, they can be classified into 2 main groups Benign (non-cancerous) and malignant (cancerous)
36
Malignant bone tumors categorization
primary = bone itself
secondary = metastasize to bone from another source.
37
four primary bone tumors
1. osteosarcoma
2. chondrosarcoma
3. Ewing's sarcoma
4. osteochondroma (bengin)
38
osteosarcoma
- affects mainly children and elderly
- develops from osteoblasts
- most common type of cancer
- occurs mostly in the metaphyseal of long bones
- possible amputation
- treatment includes surgery/amputation and chemo
39
osteosarcoma imaging protocal
three phase - 99mTc -M, H
early imaging
1. dynamic - 3s/frame over primary affected region (128*128)
2. early blood pool statics - 500K or 120s/image of AOI (128*128)
2. WBBP - 25cm/min (1024*256)
delayed imaging
3. statics - 500K or 300 images over AOI (256*256)
3. whole body - 10cm/min (1024*256)
3. SPECT/CT around AOI 64 stops @ 15s per head
40
chondrosarcomas
are malignant bone cancer starts in cartilage cells
- found in pelvis and femur, humeros, ribs, ear and larynx
- slow growing
41
chondrosarcoma types
classified by appearance and genetics
- conventional
- clear cell
- de-differentiated chondrosarcoma
42
chondrosarcoma treatment
surgery, radiation or chemo therapy
43
chondrosarcoma imaging protocol
three phase - 99mTc -M, H
early imaging
1. dynamic - 3s/frame over primary affected region (128*128)
2. early blood pool statics - 500K or 120s/image of AOI (128*128)
delayed imaging
3. statics - 500K or 300 images over AOI (256*256)
3. whole body - 10cm/min (1024*256)
44
Ewing's sarcoma
- most frequently occurs in teens
- develops from cells if the mesenchyme in bone marrow most frequently in long bones
- pain, swelling, fever and possible leukocytosis
- some present with metastatic disease
- treatment chemo, radiation or surgery
45
Ewings imaging protocal
three phase - 99mTc -M, H
early imaging
1. dynamic - 3s/frame over primary affected region (128*128)
2. early blood pool statics - 500K or 120s/image of AOI (128*128)
2. WBBP - 25cm/min (1024*256)
delayed imaging
3. statics - 500K or 300 images over AOI (256*256)
3. whole body - 10cm/min (1024*256)
3. SPECT/CT around AOI 64 stops @ 15s per head
a returning patient may only need a whole body scan and SPECT/CT
46
osteochondroma
bengin tumors common in children, one of the most common types of tumours, developed by growth plates.
47
types of osteochondromas
1- sessile - attached directly to the bone
2 - pedunculated - connected to bone by a stalk or stem like structure.
48
osteochondroma symptoms
generally none if any they include, pain, bump or swelling near a joint, limited motion, or pressure on tissues or nerves
- may need surgery
49
osteochondroma imaging protocol
three phase - 99mTc -M, H
early imaging
1. dynamic - 3s/frame over primary affected region (128*128)
2. early blood pool statics - 500K or 120s/image of AOI (128*128)
2. WBBP - 25cm/min (1024*256)
delayed imaging
3. statics - 500K or 300 images over AOI (256*256)
3. whole body - 10cm/min (1024*256)
3. SPECT/CT around AOI 64 stops @ 15s per head
50
secondary tumours
metastatic bone disease
- 65% of individuals with advanced cancer will develop bone metastases during their journey
- treatment aims to relieve symptoms, prevent complications and improve survival using surgery, radiations or chemo, systemic therapies and supportive care
51
types of metastic bone lesions
1. osteolytic - appear as regions of bone where there is a loss of density or structure, weakening affected areas
2. osteosclerotic lesions - areas of increase bone density or thickening on bone tissue
- can be benign or malignant
52
most common osteolytic bone cancers
- multiple myeloma (cancer of plasma cells)
- primary bone lymphoma
- metastatic bone cancer
53
osteolytic bone imaging protocol
two phase scan - Tc M, H
early imaging
1. EBP statics - 500K or 120s per image over primary region (128*128)
1. WBBP - 25cm/min (1024*256) @ 5 min
delayed imaging
2. WB - 10cm/min (1024*256)
2. statics - 500K or 300s images over AOI (256*256)
2. SPECT/CT AOI + others at 64 stops @ 15s per head
54
osteosclerotic bone lesions can be caused by many conditions including
- metastatic cancer
- pagets disease of bone
- osteopetrosis genetic disorder characterised by abnormally dense, brittle bones
- infection
55
osteosclerotic bone lesions appearance on imaging
areas of increased density
management - involved addressing underlying condition
superscan - metastatic lesions are uniform across entire skeleton
56
osteosclerotic imaging protocol
two phase scan - Tc M, H
early imaging
1. EBP statics - 500K or 120s per image over primary region (128*128)
1. WBBP - 25cm/min (1024*256) @ 5 min
delayed imaging
2. WB - 10cm/min (1024*256)
2. statics - 500K or 300s images over AOI (256*256)
2. SPECT/CT AOI + others at 64 stops @ 15s per head
57
flare phenomenon or "osteoblastic FP"
- chemotherapy treatment < 3 months
- lesions appear 'hot' visible
- positive response to chemo agent less lesions
- if new lesions appear = disease progression
58
prostate cancer rangers
normal PSA range = 0-4 ng/ml
borderline PSA range = 4 - 10 ng/ml
high PSA range = greater then 10 ng/ml
which significantly increases the suspicion of prostate cancer but can be caused by other things
59
benign Bone Tumors
osteoid osteoma is a rare benign tumor effecting the young
- may cause pain but generally doesn't spread
- most common treatment uses CT guided radio frequency ablation
60
osteoid osteoma imaging protocol
three phase - 99mTc -M, H
early imaging
1. dynamic - 3s/frame over primary affected region (128*128)
2. early blood pool statics - 500K or 120s/image of AOI (128*128)
delayed imaging
3. statics - 500K or 300 images over AOI (256*256)
3. SPECT/CT around AOI 64 stops @ 15s per head
no need for WBBP or WB scan
61
fibrous dysplasia
is a rare bone disorder characterised by abnormal growth or development of fibrous tissue with in the bone
- can effect one or more bones
- caused by genetic mutation that leads to the replacement of normal bone with tissue
62
treatment for fibrous dysplasia
depends on severity many include medication some may need surgery
63
scans for fibrous dysplasia
38.7 time 4 = 154.8 with overlap 36.5 times 4 = 146
= 4 bed steps
64
imaging protocol for fibrous dysplasia
two phase scan - Tc M or H
early imaging
1. WBBP - 25cm/min (1024*256)
delayed imaging
2. WB - 10cm/min (1024*256)
2. statics - 500K or 300s/image of AOI (256*256)
2. SPECT/CT AOI -64 stops @ 15s
65
Pagets disease (osteitis deformans)
- is an idiopathic condition of chronic bone disorder, abnormal bone remodeling
- generally diagnosed via blood test looking at alkaline phosphatase and imaging studies
- can be either mom or ploy static
66
pagets disease treatment and symptoms
medications, pain relief and physical therapy
- pain develops slowly, disease doesn't spread to normal bones
- headaches and hearing loss when in head
67
pagets disease imaging protocol
one or two phase
1. WBBP - 25cm/min (1024*256)
delayed imaging
2. WB - 10cm/min (1024*256)
2. statics - 500K or 300s/image over AOI (256*256)
2. SPECT/CT of AOI 64 stops @ 15s
68
Rheumatoid Arthritis
- autoimmune disease, uses blood test to find antibodies.
- inflammation of the joints - proliferative synovitis
- progressive destruction of articular cartilage
risk factors
- genetic predisposition - HLA genes
69
Rheumatoid arthritis imaging protocol
one or two phase
1. WBBP - 25cm/min (1024*256)
1. EBP hands and feet - 500K or 120s per image (128*128)
delayed imaging
2. WB - 10cm/min (1024*256)
2. statics - 500K or 300s/image over AOI (256*256)
2. SPECT/CT
some clinics only do one phase
70
what is maximum intensity projection (MIP)
- is an imaging techinque used in CT, MRI, SPECT and PET
- MIP creates a 2D projection image from a 3D dataset that highlights the maximum intensity value along the line of sight for each pixel in the projection
71
avascular necrosis (AVN) (osteoriecrosis)
is a condition where bone tissue dies due to a lack of blood supply
- typically effecting the epiphysis of long bones at weight-bearing joints
72
risk factors for AVN
- trauma or injury
- excessive alcohol consumption
- radiation therapy
- joint stress/ overuse
- steroid use
- medical conditions
- organ transplant
- genetics
73
symptoms of AVN
-joint pain
- limited range of motion
- stiffness
- joint instability
74
diagnoses of AVN
- clinical examination, imaging studies like bone scans which can detect early stages by showing areas of decreased blood flow in affected bones
75
AVN imaging protocol
three phase - 99mTc -M, H
early imaging
1. dynamic - 3s/frame over primary affected region (128*128)
2. early blood pool statics - 500K or 120s/image of AOI (128*128)
2. WBBP - 25cm/min (1024*256)
delayed imaging
3. statics - 500K or 300 images over AOI (256*256)
3. whole body - 10cm/min (1024*256) + additonals
3. SPECT/CT around AOI 64 stops @ 15s per head
76
osteomyelitis
is an infection of the bone typically caused by bacteria with bone scanning it is possible to detect and evaluate osteomyelitis
77
purpose of bone scanning osteomyelitis
- identify areas of bone infection
- assess the extent and severity of the infection
- monitor response to treatment
78
radiotracers used for osteomyelitis
Tc - MDP or HDP, Tc HMPAO, F-FDG PET/CT scanning is also viable option
79
categorization of osteomyelitis
acute - initial stage of infection, rapid onset of symptoms
chronic - occurs if acute is not treated or controlled characterised by persistent infection and inflammation of the bone leading to necrosis and formation of abscesses
80
osteomyelitis classified by route of infection
hemotogenus osteomyelitis - bacteria from distant site travel via blood stream into bone
contiguous osteomyelitis - occurs when an infection spreads to the bone from adjacent infected issue
81
osteomyelitis differentiated based on causative organism
bacterial osteomyelitis - most common form caused by bacteria
fungal osteomyelitis - caused by fungal infections
82
osteomyelitis imaging protocol
three phase - 99mTc -M, H
early imaging
1. dynamic - 3s/frame over primary affected region (128*128)
2. early blood pool statics - 500K or 120s/image of AOI (128*128)
2. WBBP - 25cm/min (1024*256)
delayed imaging
3. statics - 500K or 300 images over AOI (256*256)
3. whole body - 10cm/min (1024*256) + additional views
3. SPECT/CT around AOI 64 stops @ 15s per head
83
osteomyelitis scintigraphic appearance
if bone scan is positive, follow up with an infection imaging scan
84
prosthetic loosening
refers to the detachment or movement of an artificial joint from the bone is was implanted in causes
- wear and tear
inadequate fixation of the prosthetic to the bone
- infection
- bone resorption around the implant
falls/accidents
symptoms
- pain in joint
- swelling or inflammation
- decreased range of motion
- instability
- difficulty preforming daily tasks
85
prosthetic loosening diagnoses
- clinical evaluations by a physician
- imaging studies
- bone scan
86
prosthetic loosening imaging protocol
three phase - 99mTc -M, H
early imaging
1. dynamic - 3s/frame over primary affected region (128*128)
2. early blood pool statics - 500K or 120s/image of AOI (128*128)
2. WBBP - 25cm/min (1024*256)
delayed imaging
3. statics - 500K or 300 images over AOI (256*256)
3. whole body - 10cm/min (1024*256)
3. SPECT/CT around AOI 64 stops @ 15s per head
