This page is best viewed in Firefox.

Welcome to the Hypoxia Imaging Website

Welcome to the Hypoxia Imaging website. This site is hosted by the laboratories of Drs. Sydney M. Evans and Cameron J. Koch in the Department of Radiation Oncology at the University of Pennsylvania School of Medicine (Stephen M. Hahn, chairman) - also home of OncoLink.

We hope that will be visited by everyone interested in this field. You will find all aspects of EF5 technology as well as examples of the work done at Penn on this website; we invite anyone using EF5 to post their images here. We also invite submissions on any aspects of hypoxia to this site. Our goal is to create a forum to further the study of hypoxia by exchanging ideas from all points of view. If you have material you would like to submit, please contact our webmaster at

There are numerous approaches to measure hypoxia in tissues (see review papers). The focus of the current website is the use of EF5, a compound developed at the University of Pennsylvania by Dr. Cameron Koch and developed with the help of Dr. Sydney Evans. Drs. Evans and Koch chose to develop the EF5 (rather than other potential hypoxia imaging agents) because its characteristics allow it be used in cells, animal tissues and human tissues with an invasive (biopsy based) and/or non-invasive (PET) imaging approach. Almost any tissue or disease can be investigated using EF5; on this website you will find examples of studies in animal and human tumors, normal tissue and non-neoplastic diseases such as stroke and patent ductus arteriosus.

One of the advantages of EF5 over other hypoxia markers is that the resultant images can be calibrated to provide quantitative data, e.g. specific pO2 values in each cell. For example, we generated oxygen maps of tumors using these techniques (reference - Human Tumors #3). Determination of these values requires using a standard to calibrate the camera and keeping track of the camera exposure values. The intensity values of calibrated images are directly related to actual tissue pO2 values. Such quantitation also requires a separate in vitro studies referred to as "cube-binding" studies (references). The data from these studies provides a reflection of the nitro-reductase levels in individual patient or animal tissues to which the in situ binding can be compared. Thus, EF5 binding is expressed as a percentage of cube reference binding, e.g. a percentage of the maximum binding the tissue is capable of. As a result, these images provide information regarding not only where hypoxic areas are, but also data regarding the level of hypoxia, e.g. the tissue pO2.

We have written up a series of SOPs (standard operating procedures) including how to make and use the appropriate reagents for EF5 analysis. Feel free to download and use them in your EF5 papers and grants. We have received numerous phone calls in the past from scientists protesting that “EF5 doesn’t work for me!” Frequently, some or many aspects of our recommended procedures have been modified. We have spent years optimizing our techniques and have probably tried (and discarded) many of the modifications that have been tried. So, at least for the first time, follow directions!

Comments? Questions? E-mail