Foster, Kenneth R.*; Moulder, John E.â€
*Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104; †Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI 53226.
The authors declare no conflicts of interest.
For correspondence contact: K. Foster, Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, or email [email protected].
(Manuscript accepted 9 May 2013)