Nuclear Medicine Quality control

Uniformity gamma camera divide by flood source image No correction Energy correction E + Linearity E + L + Flood correctie

Uniformity PET camera Uncorrected Corrected sinogram Blank scan projection Correction: energy uniformity dead time

QC gamma camera Whole Body bed motion uniformity pixel size SPECT Planar uniformity energy resolution linearity spatial resolution dead time sensitivity pixel size Whole Body bed motion uniformity pixel size SPECT center of rotation detector position Phantom

dead time straightforward: decaying source two sources with (nearly) same activity

Center of rotation

Detector position

well counter dose calibrator survey meter

well counter NaI(Tl) PMT lead shielding

well counter lead shielding NaI(Tl) PMT a H sens = 1 2 1+ 𝐷 𝐷 2 + 𝐻 2 sensitivity

gas filled detectors - - - + - applied voltage output current ionization chamber proportional counter Geiger-Müller - - - + + + - - - + - - -

dose calibrator isotope selection

dose calibrator - + + - output current = const x air kerma (or Ar kerma) function of isotope energy!

dose calibrator with Cu filter

survey meters ionisation detector (Xenon)

survey meters scintillator (NaI(Tl))

contamination monitor, spectrometer NaI(Tl) scintillation crystal

contamination monitor

Image analysis

SUV: standard uptake value somewhat controversial only valid if procedure is standard: time between injection and image condition of patient ... used all the time!

example: analysis of heart images

Image analysis 18F-FDG 13N-NH3

perfusion + metabolism

Gated PET

Partial volume constant activity big pixels

Partial volume constant concentration finite resolution perfect resolution Partial volume constant concentration finite resolution finite resolution Recovery Spill-over

Partial volume constant activity finite resolution

Gated MIBI, thickening 3 4 2 5 1 6 2 4 6 8 200 400 600 800 1000 7

Tracer kinetic modelling

Dynamic PET 13N-NH3 perfusion study 20 s. 40 s. 3 min 20 min

Dynamic PET 11C-acetate perfusion/oxidative metabolism study

Kinetic modelling k3 K1 k2 k4 Extra- Blood Metabolized vascular 0.1 0.1 0.2 0.3 0.4 0.5 0.6 0.7 100 200 300 400 500 0.05 0.1 0.15 0.2 0.25 0.3 100 200 300 400 500

3 comp model C’p C’E C’M Glucose: k’3 K’1 k’2 k’4 - metabolized = 0

3 comp model Cp CE CM K1 k2 k3 k4 FDG: not metabolized but accumulated

Laplace transform

3 comp model Cp K1 k3 FDG: CE CM k2

3 comp model Lumped constant: Glucose consumption:

Motion correction 16 17 15 14 12 13 11 11C-Acetate

Tracer kinetic modelling: NH3 0.1 0.2 0.3 0.4 0.5 0.6 0.7 100 200 300 400 500

parametric modelling: acetate

Image quality

Bias and variance A is better than B! more regularisation variance which method is better? B A bias

Software evaluation nice  correct image quality is task dependent simulation, phantom, (animal), clinical

Dosimetry

Dosimetry Q(photons, electrons, positrons) = 1 Q(neutrons, protons) = ..10.. Q(a-particles) = 20 MIRD formalism (SNM)

effective dose A B

L = 4 cm R = 2 cm D = 10 cm d = 2 cm = 0.15 /cm (140 keV) m = 0.095 /cm (511 keV) 1 MBq 123I: gamma: 0.84 of 159 keV electron: 0.13 of 127 keV halflife: 13 h 1 MBq 18F: 1 positron of 250 keV 109 min

dosimetry For organs with uptake: 3D VOIs pixelwise MBq/cc measurement => Total organ activity

residence times evaluation of tracer for ORL-1 receptors in the brain Residence time (hr) for the liver: S1: 0.4567 S2: 0.5310 S3: 0.3940 Residence time (hr) for the thyroid: S1: 0.0017 S2: 0.0017 S3: 0.0013 evaluation of tracer for ORL-1 receptors in the brain

Olinda: MC-based dosimetry MIRD Dose Estimate Report No. 19: Radiation Absorbed Dose Estimates from 18F-FDG

dosimetry background radiation: ..2.. mSv / year = 5.5 mSv / day = 0.2 mSv / hour patient: 18F-FDG, 300 MBq  6 mSv 99mTc-MIBI 740 MBq  11 mSv

the end