Table 4.

Calculation of light-path parameters for infrared imaging

Pathway description	Factor	Value
Light source	Input to produce luminescence	300 mW = ~ 1.6 × 1018 photons
α	Attenuation between light source and NP	0.1 ×  at 4 cm
β	Absorption cross section of one single NP	1 × 10−16 cm2
γ	Quantum yield of NP	0.3
δ	Attenuation of NP-emitted light at distance to detector	0.1 ×  at 4 cm
ε	Solid angle of detector at 4 cm seen from the NP	~1/5000 = 2 × 10−4 at 4 cm
ζ	Detection efficiency of detector	0.5
η	Total noise in the system	1 × 10−6 counts/mm2.second
α x β x γ x δ x ε x ζ x η −1	$1.6\times {10}_x^{18}0.1_{x}1\times {10}_x^{-16}0.3_{x}0.1_{x}0.2\times {10}_x^{-4}0.5_{x}1\times {10}^{-6}$	4.8 × 10−11

At this S/N ratio (4.8 × 10⁻¹¹) the signal is not detectable