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Erno Sajo

Erno Sajo, Ph.D. Professor, Director - Medical Physics


Medical Physics & Radiological Science; External Member, Hungarian Academy of Sciences

Research Interest

I study the fundamental interactions between radiation and biological matter with particular emphasis on cancer therapy. The description of the involved phenomena requires the understanding and solution of Boltzmann's transport equation, one of the most complex and most difficult theories of nature. The same equation, applied at the hydrodynamic limit, describes the transport and interactions of colloids, including aerosols and hydrosols at the micron and nano-scales. Thus, two seemingly different physical phenomena are brought together and have significant commonality. Hence, my field of interest is radiation biology, radiation transport, and aerosol transport or colloid interface science. The latter is part of nano science, and it has found applications, or the promise thereof, in cancer treatment. 

In radiation science, my current research centers on deterministic computations of energy deposition in the nanoscale, at the interface of high-atomic number (high-Z) nanoparticles and nanolayers. This also includes the exploration of the effect of electromagnetic fields generated by fast moving electrons across high-Z/low-Z interfaces. 

In radiation biology I work on understanding the types of chromosomal and DNA damages, including the risk of heritable intragenic mutations, caused by high vs low linear energy transfer radiation. This includes dose computations at the micro- and nano- scales in charged particle disequilibrium. Application of this work ranges from Auger therapy to secondary cancer induction, and extends to investigating the possibility of targeting biomolecules other than the DNA in cancer therapy. 

Other related areas where I have been active is prostate brachytherapy, where with ML Williams we developed a new method to directly assay the prostate dose following permanent interstitial implant, without having to explicitly find the locations of implanted seeds - an error-prone procedure, which is currently widely used. A US Patent has been awarded. 

In colloids, I am interested in nanoparticle cancer treatment and in aerosol transport - two related areas of colloid interface science whose physical and mathematical description bear similarities. In confined spaces particles undergo dynamic sequential many-body interactions with or without chemical reactions while transported in the medium. My research group has developed a computational aerosol transport model, which tracks the aerosol phase space and yields the time-resolved size-specific aerosol distribution in space following the release of aerosol species in arbitrary geometry and arbitrary initial size distribution. This can be used for computing particle concentrations in the airways as well as in open or closed atmospheres.

Educational Background

Ph.D., 1990 - University of Lowell