Applications of Positron Annihilation Spectroscopy to Life Science

Abstract

Positron annihilation spectroscopy (PAS) is a novel method that can provide molecular-level information about complex biological and macromolecular structure in a manner which is different, but complementary, to conventional medical and biochemical research methodology. Positron annihilation lifetime spectroscopy (PALS) and Doppler broadening energy spectroscopy (DBES), coupled with a slow positron beam have been extensively applied to the life science research recently. These techniques provide new information about the atomic and molecular level free-volume and void sizes, and their distributions 0.1 nm to a few nm, molecular bonding, structures at depth-layers, and phase transitions. This paper is to review recent research on positron annihilation spectroscopy applied to the area of life science and also focus on current bioscience-related work in the positron group at the University of MissouriKansas City (UMKC).

Prospects and Clinical Perspectives of Total-Body PET Imaging Using Plastic Scintillators

“…In the body, the mean lifetime of ortho-positronium varies from approximately 1.8 ns in pure water to approximately 4 ns in human skin. 80 Moreover, both formation probability and mean lifetime depend on the concentration of the bio-fluids and bio-active molecules 81,82 and the mean lifetime can be established in the human body with the precision of approximately 20 ps. 29 There are investigations demonstrating differences between normal and cancerous cells with changes of the positronium lifetime during dynamic processes undergoing in model and living biological systems.…”

“…29 There are investigations demonstrating differences between normal and cancerous cells with changes of the positronium lifetime during dynamic processes undergoing in model and living biological systems. [79][80][81][85][86][87][88][89][90][91][92][93][94][95] Therefore, positronium may be used as a sensor of the surrounding tissue environment, and imaging of its properties inside the patient body may serve as additional diagnostic indicator. In general, positronium imaging can be defined as a method for the position-sensitive reconstruction of positronium properties (such as mean lifetime, formation probability, and 3g/2g rate ratio) within the imaged object.…”

Detection of Atomic Scale Changes in the Free Volume Void Size of Three-Dimensional Colorectal Cancer Cell Culture Using Positron Annihilation Lifetime Spectroscopy

“…Thus, PALS has been proposed as a potential tool to detect cancer formation at the early stages of tumor development [6] , [7] . However, cellular composition of tissue samples varies from the same organism and may involve changes in the void sizes [8] .…”

Positron annihilation lifetime spectroscopy study of polyvinylpyrrolidone‐added polyvinylidene fluoride membranes: Investigation of free volume and permeation relationships

“…Positron annihilation lifetime measurements were determined using a conventional fast–fast gamma coincidence method at 25 °C. The time resolution of the spectrometer was <350 ps, determined by using a 60 Co source in the 22 Na energy window settings . Samples were dried at ambient conditions for at least 30 min before preparing the PALS sample.…”