Table 1.

Parameter list for Photofrin and values at 630 nm

Symbol	Definition [4]
k0	Photon absorption rate of sensitizer per sensitizer concentration
k1	Bimolecular rate for 1O2 reaction with ground-state photosensitizer
k2	Bimolecular rate of triplet sensitizer quenching by 3O2
k3	Decay rate of first excited singlet state sensitizer to ground state sensitizer
k4	Rate of monomolecular decay of the sensitizer triplet state
k5	Rate of first excited triplet state sensitizer to ground state sensitizer
k6	1O2 to 3O2 decay rate
k7	Bimolecular rate of reaction of 1O2 with biological substrate [A]
Symbol	Definition	Value	References
SΔ	Fraction of triplet-state sensitizer-3O2 reactions which produce 1O2	0.5	[4]
δ	Low concentration correction term	33 (μM)	[7]
ε	Extinction coefficient of sensitizer	0.0035 (cm−1 μM−1)	[2]
α	k7[A]/k6	0.95	[3]*
β	k4/k2	11.9 (μM)	[3]
γ	k5/(k3 + k5)	0.8	[2]
κ	k1/k6	7.2 × 10−5 (μM−1)	[3]*
η	ε/hν	0.0019 (cm2 mW−1 s−1)	based on [2]
SΔγηα/(1+α)**		0.0037 (cm2 mW−1 s−1)	[3]*

^*The calculation of the parameter values are based on tumor spheroid studies [3].

^**This value corresponds to the oxygen consumption rate per light fluence (in mW/cm²) per initial sensitizer concentration (in μM).