Nuclear medicine uses radiopharmaceuticals and imaging techniques like PET and SPECT scans to assess organ function and detect diseases. Some key applications include using F-18 FDG PET scans to identify cancer metastases based on increased glucose metabolism in malignant cells, Tc-99m sestamibi scans to detect myocardial ischemia, Tc-99m DMSA renal scans to assess kidney function, and somatostatin receptor imaging with radiolabeled octreotide to localize neuroendocrine tumors. PET provides superior detection of bone metastases compared to bone scans or whole-body MRI. Important considerations for nuclear medicine exams include selecting the appropriate radiotracer and ensuring normal blood glucose levels for oncology FDG PET scans
11. Abnormal bone scane
Super scan โข In diffuse metastatic ds of bone
โข In diffuse metabolic ds of bone
โข Renal failure
OM โข Increased uptake in all 3 phases of bone scan
Mickey mouse sign โข Pagets ds
Hot bone scan โข Increased uptake in site where there is increased
uptake -๏ neoplasm trauma infection avscular
necrosis
Cold scan โข In multiple myeloma
โข Histiocytosis
โข Neuroblastoma
โข RCC
โข Thyroid carcinoma
12. Super scan
โข Increased uptake in skeleton
โข No background radiotracer activity
โข But kidneys are not visualised
โข In diffuse metastatic ds of bone
โข In diffuse metabolic ds of bone
โข Renal failure
13. Mickey mouse sign in pagets disease
โข d/t increased uptake in
pedicles & spinous process
14.
15. Big black beard / linoln sign
in pagets disease
โข Increased condylar to condylar uptake in bone
scan
16. For infections of bone / osteomyelitis
โข Gallium scan
โข Indium labelled WBC scan (except in case of respiratory tract
infections )
โข Increased uptake in all 3 phases
18. Nuclear medicine in heart
Myocardial perfusion studies โข Thallium 201 (MC used)
โข Tc99m tetrophosmin
โข Tc99m sestamibi (MIBI scan)๏ area of infarct
appears cold
Myocardial infarct imaging โข Tc99 pyrophosphate (area of infarct appears hot)
MUGA scan โข Tc99m labelled RBC are used
19. Myocardial perfusion scan
โข SPECT scan is used To assess blood flow (perfusion )
โข Using thallium 201 / Tc99 labelled tetrofosmin /Tc 99m labelled sestamibi
โข Low perfused area appears cold (d/t decreased uptake of radioactive
material)
20. Stress thallium study
โข Stress is given by physiologically / with dobutamine
โข At peak of stress ๏ inject thallium
โข Uptake by normal myocardium with normal blood flow ๏ hot areas
โข Ischemic myocardium ๏ cold areas
Reversible ischemia Ischemia on exercise but not on rest
Irreversible ischemia Ischemia both @ rest & execise
21. Myocardial infarct scintigraphy
โข Using Tc pyrophosphate
โข Uptake by infarcted myocardium
โข Infarct ๏ hot areas
โข Blood flow is not assessed by this scan
22. โข Gold standard for myocardial viability ๏ PET scan
โข Best investigation to differentiate b/w myocardial scar & hibernating
myocardium ๏ PET
Cardiac PET uses
Myocardial metabolism FDG PET scan
Myocardial perfusion โข radioactive ammonia (NH3)
โข H20
โข Rubidium 82
Rubidium 82 ๏ non cyclotron isotope used in PET scan
23. MUGA scan
โข method for assessment of LV functionmeasure ejection fraction
โข ECHO can also be used
โข most accurate is MRI
โข 99mTc-labelled albumin or red cells that are uniformly distributed
throughout the blood volume /
24. Tc 99m labelled RBC is used for
โข Haemangioma
โข GI bleeding
โข Splenic disease
โข Cardiac ventriculography
25. Nuclear medicine in GIT
Tc99m labelled RBC โข Minimal lower GI Bleeding
โข Sensitive test (0.1ml/min)
Tc99m pertechnate โข Pertechnate is taken up by gastric mucosa ๏ to
detect ectopic gastric mucosa
Tc99m sulphur colloid โข Taken by RE cell
โข To detect Focal nodular hyperaplasia (FNH) also
used in accessory spleen & abscess
โข IOC for upper GI bleed ๏ endoscopy
โข IOC in lower GI bleed ๏ mesenteric angiography
/ Tc99 RBC
26. Lower GI bleed
Mesenteric angiography Tc 99 RBC
Can detect 0.5 ml/min blood loss Can detect 0.1 ml/min blood loss
28. Renal radionuclide imaging
โข Dynamic renal scintigraphy ๏ functional imaging Static renal scintigraphy
Tc99 DTPA ๏ GFR estimation Tc99m DMSA
โข To assess cortical function / corticomedullary
differentiation/ functional mass / scarring of VUR
Tc99 MAG 3 ๏ best for dynamic renal scintigraphy
I123 โOIH ๏ effective renal plasma flow
29. Dynamic renal scintigraphy
Tc99m DTPA ๏ GFR estimation Tc99m MAG3
โข DTPA ๏ neither reabsorbed / secreted
โข Used to measure GFR
โข Demonstration of VUR
โข Differentiate obstruction from stasis by diuretic
DTPA scan
โข To assess transplanted kidney
โข MAG3 is secreted as well as filtered
โข Best study for renal function
โข Glomerular + tubular function
Captopril DTPA is used for detecting reno vascular HTN
30. Ventilation perfusion scan
Ventilation Using inert gases like krypton or xenon
Perfusion Tc99m microaggreagtes of albumin
Tc99m labelled RBC
โข V/Q scan ๏ to detect Pulmonary thromboembolism in
pregnancy & In iodine allergy contrast cant be used
โข IOC in PTE ๏ MDCT with contrast
31. To localise parathyroid adenoma in primary
hyperparathyroidism
โข 99_Tc sestamibi scan.
โข After one hour of injection, uptake is done by both thyroid and parathyroid
gland.
โข After 3 hrs uptake evidence is there only in parathyroid. So by computer
subtraction adenoma is located.
โข Tc โ thallium substraction scan can also be used
32. Radioactive iodine
T1/2 Uses
I131 8 days โข Systemic therapy of thyroid metastasis
โข Emits both ฮฒ&ฮณ rays
โข ฮฒ rays๏ killing thyroid cells
I 125 60 days โข Radioimmunoassay
โข Brachytherapy of prostate
I124 4 days โข Used in PET scanning
I 123 13 hrs โข Functional thyroid scintigraphy
โข Not available in india ๏ done by Tc99
pertechnetiate
โข Radioactive iodine uptake
Stable isotope of iodine ๏ I 127
33. โข In case of neuroendocrine tumours ๏ carcinoid , glucaganoma ,
VIPoma
โข Somatostatin receptor scintigraphy
โข Octreotide scintigraphy
โข insulinoma
โข IOC ๏ EUS
โข As somatostatin receptor is negative
40. PET
โข This technique has been used in the
โข evaluation of solitary pulmonary nodules and as
โข aid to staging lung cancer,
โข identification of mediastinal lymph node involvement by malignancy.
โข Radiation induced necrosis
45. Annihilation
โข Positron emitted from photon
emitting radionucleitide ๏
combine with electron to form
gamma rays of energy 511 KeV
โข Gamma rays Are detected by
PET scanners coupled to
photomultiplier tubes
46. โข Gamma photon are
detected by PET Scanner
composed of scintillation
crystals made up of
โข Bismuth germinate
โข Cerium doped lutetium
oxysilicate
โข Cerium doped gadolinium
silicate
47.
48. โข PET
โข It is increasingly being used to identify malignant lesions in the lung based
on their increased uptake and metabolism of glucose.
โข The technique involves injection of a radiolabeled glucose analogue, 18f-
fluoro-2-deoxyglucose (fdg), which is taken up by metabolically active
malignant cells. However, fdg is trapped within the cell following
phosphorylation, and the unstable fluorine 18 decays by emission of
positrons, which can be detected by a specialized pet camera or by a
gamma camera that has been adapted for imaging of positron-emitting
radionuclides.
49. Cyclotron
โข Used to produce artificial
isotopes
โข F18 is produced in a cyclotron
by bombarding O18 enriched
water with high energy
photons in a cyclotron
โข Other positron emitting C11
N13 & O15 can also be
produced
โข 18FDG is most commonly
used
T1/2
Oxygen 2 minutes
Nitrogen 10 minutes
Carbon 20 minutes
Flourine 110 minutes
50. Role of 18 FDG in PET Scan
โข In oncology
โข Warburg effect in malignant cells
โข Aerobic glycolysis
โข Even in presence of O2 no TCA cycle
โข Malignant cells have increased glucose utilisation d/t upregulation of
hexokinase activity
โข Increased glucose uptake ๏ increased 18 FDG uptake
52. 18 FDG enters glycolysis ๏ undergoes
phosphorylation but donot undergo
further metabolism
53. Uses of 18 FDG PET
โข Staging of various tumours
โข Identifying metastasis
โข Rx response & follow up
โข Used to detect tumour recurrence
โข Differentiate post surgical scarring / post RTx fibrosis from tumour
recurrence
54. 18 FDG PET
False positive (even in absence of malignancy) False negative
โข c/c infections (TB)
โข Brown adipose tissue
โข Bronchoalveolar carcinoma (low mitotic &
metabolic activity)
โข Carcionid (low mitotic & metabolic activity)
โข Brain metastasis
โข In fasting & DM (increased uptake by all cells)
Blood glucose should be normal
before PET scanning
55. 18 FDG PET in brain
โข Greater uptake in brain & liver
โข Not useful to detect brain metastasis
โข 11C methinonine PET is better than 18 FDG PET to detect brain
metastasis
โข Investigation of choice for brain metastasis is
MRI
โข Investigation of choice for recurrent brain
tumour ๏ PET scan (recurrence is seen against
post surgical or post RTx scarring)
57. Bone metastasis
โข IOC is PET
โข PET scan >>> whole body MRI >>>bone scan
โข Na + F- PET scan is better than 18 FDG
โข 18 FDG cannot detect brain & liver metastasis
58. PET scanning in heart
โข 2 types can be used
โข N13 ammonia PET
โข 18 FDG PET scan
N 13 ammonia PET ๏ to
detect myocardial perfusion
18 FDG PET ๏ to detect
myocardial viability
/metabolism
Scar tissue -ve -ve
Hibernating myocardium -ve +ve (ischemic heart
preferentially uses glycolysis
rather than fatty acids)
โข To differentiate hibernating myocardium
form scar tissue
โข Only in hibernating myocardium stenting can
be done & it is useless in case of scar tissue
61. PET scan in carcinoid syndrome
โข Carcinoid syndrome ๏ low mitotic & low metabolic activity ๏ 18 FDG
will be negative
โข Carcinoid syndrome ๏ octreotide PET & DOTATOC PET are used