A method converts a two-dimensional object to a two-dimensional distance field. Other embodiments are disclosed. The traveling body is pinched between the driven rollers and driving gears. If the erasure decoding is successful, then the decoded user data is output. Also described are methods of treatment include administering at least one chemical entity as a single active agent or administering at least one chemical entity in combination with one or more other therapeutic agents. The system is adapted for easy and convenient operating room use during surgical procedures.