The present invention describes light source devices to provide white and blue (401-510 nm) light for the in vivo identification of diseased tissue using fluorescence based tissue targeting. The light source devices are configured with a variety of LED lights capable of emitting white and blue light with at least one excitation wavelength in the range from about 401 nm to about 500 nm (for example, 470 nm to 495 nm) to irradiate an in vivo body part of a subject containing tumor or diseased tissue. The tumor or diseased tissue has fluorophore-tagged targeting constructs attached. The fluorophores used in the targeting constructs have emission spectra greater than 515 nm. The fluorescence emanating from the fluorescent targeting construct in response to the excitation wavelength is directly viewed with long-pass filtered (515 nm) lenses and is used to determine the location and/or surface area of the diseased tissue in the subject. Fluorescence based surgical identification provides more accurate disease resection.
