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Table 1 Model parameters

From: Potential and pitfalls of 89Zr-immuno-PET to assess target status: 89Zr-trastuzumab as an example

Parameter

Abbreviation

Unit

Value

References

Tumor tissue

 Plasma volume fraction

pvf

0.04

[9,10,, 10]

 mAb accessible interstitial volume fraction

ivf

0.2

[9, 11, 12]

 Extravasation rate constant

kev

h−1

0.012

[13, 15]

Target—HER2

 Initial target concentration

T0

nM

0–27001

[4, 14]

 Equilibrium binding affinity

KD

nM

5

[14]

 Target synthesis rate

ksyn

nM· h−1

kdeg·T0

[14, 16]

 Target degradation rate

kdeg

h−1

0.19

[14, 16]

 Target-mAb internalization rate

kint

h−1

0.19

[14, 16]

Input

 Injected Dose of 89Zr-mAb in plasma

IDl

mg

3

[4]

 Injected Dose of mAb in plasma

IDu

mg

47

[4]

 Exchange rate (plasma to normal tissue)

k1

h−1

0.0722

[4, 5]

 Exchange rate (normal tissue to plasma)

k2

h−1

0.1366

[4, 5]

 mAb clearance rate from plasma

kcl

h−1

0.0083

[4, 5]

Fixed

 Plasma volume (fixed at 3 L)

Vp

L

3

 

 Tumor volume (fixed at 1 mL)

Vt

L

0.001

 

 Body weight (fixed at 80 kg)

BW

kg

80

 

Calculated

 Target concentration

T

nM

  

 Amount of (89Zr-)mAb in plasma

Xp,l and Xp,u

nmole

  

 Amount of (89Zr-)mAb in remainder of body

XRob,l and XRoB,u

nmole

  

 Amount of (89Zr-)mAb in interstitial space

Xi,l and Xi,u

nmole

  

 Fraction of (89Zr-)mAb unbound in ivf

fu

  

 Amount of residualized 89Zr

Xr

nmole

  

 Concentration of 89Zr in the tumor

Ct

nM

  

 Standardized uptake value

SUV

  
  1. 1The relation between IHC score and HER2 concentration has been described in literature: IHC 0 < 30 nM, IHC 1 = 30–120 nM, IHC 2 = 120–590 nM, IHC 3 > 590 nM [14]. These numbers reflect estimated expression levels before therapy, when target synthesis and degradation are in balance [14, 16]