Light Penetration into Brain

Farzad Salehpour, Saeed Sadigh-Eteghad, Javad Mahmoudi, Farzin Kamari, Paolo Cassano, Michael Richard Hamblin

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review


This chapter explores the critical aspect of light penetration into the brain, which is essential for understanding the therapeutic potential of photobiomodulation (PBM). It discusses the absorption features of biological tissue components, the penetration profiles of scalp, skull, and brain tissues, and concludes with remarks on penetration depth. Section 1 introduces the concept of light penetration in the context of brain PBM, highlighting its importance for effective treatment outcomes. Section 2 delves into the absorption features of biological tissue components, explaining how various chromophores and tissue structures impact the transmission of light through the scalp, skull, and brain. Section 3 focuses on light penetration profiles of scalp and skull tissues. Data from animal studies (3.1) and human studies (3.2) are presented, with laboratory and simulation data offering a comprehensive understanding of light transmission through these tissues. Section 4 examines light penetration profiles of brain tissues, again drawing on data from both animal (4.1) and human (4.2) studies. The laboratory and simulation data provide insights into how light interacts with the brain’s complex structure and the factors that influence penetration depth. Section 5 concludes the chapter with remarks on penetration depth, emphasizing the importance of selecting appropriate wavelengths and treatment parameters to ensure optimal light penetration for effective PBM therapy. Overall, this chapter offers a thorough analysis of light penetration into the brain, equipping readers with the knowledge necessary to design and evaluate brain PBM treatments.

Original languageEnglish
Title of host publicationSynthesis Lectures on Biomedical Engineering
PublisherSpringer Nature
Number of pages16
Publication statusPublished - 2023

Publication series

NameSynthesis Lectures on Biomedical Engineering
VolumePart F1286
ISSN (Print)1930-0328
ISSN (Electronic)1930-0336

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biochemistry
  • Biomedical Engineering


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