TRANSMITTANCE OF NONIONIZING RADIATION IN HUMAN TISSUES*

TLDR

Tissue thickness, optical absorption, and scattering largely determine light transmittance in human tissues. The study measured spectral transmittance of 400–865 nm light through skull, chest wall, abdominal wall, and scrotum. Transmittance is negligible below 500 nm for chest and abdomen, but 10⁻⁵–10⁻⁴ of blue light reaches brain and testes; overall transmittance rises with wavelength, reaching 10⁻²–10⁻¹ for skulls and scrota and 10⁻³–10⁻² for chest and abdominal walls.

Abstract

Abstract— Spectral transmittance of 400–865 nm radiation through various human structures, including the skull with scalp, the chest wall, abdominal wall and scrotum, is presented. There is essentially no visible light of wavelengths shorter than 500 nm transmitted through the chest or the abdominal wall. In contrast, 10 −5 –10 −4 of blue light can reach the brain and testes. Transmittance of all tissues increases progressively with wavelength from 600 to 814nm. The maximal transmittances are 10 −2 –10 −1 for skulls and scrota, and 10 −3 –10 −2 for chest and abdominal walls. Tissue thickness, optical absorption and scattering are major influencing factors.