Source: insighttoolkit4 Version: 4.8.1-1 Severity: serious Your package build-depends on libdcmtk2-dev, which is no longer built by src:dcmtk. You should build-depend on libdcmtk-dev now.
Note that if you want to use alternatives, then libdcmtk-dev should be the first one, as Debian buildds only look at that. Emilio