viewed with a viewing device and or that can be viewed fluoroscopically in the former case the marking substance may comprise a dye in the latter case the marking substance may comprise a contrast agent referring now to the drawings in which like reference numerals identify corresponding components fig2 a e illustrate various steps in an embodiment of a method for inspecting a plurality of internal body cavities in the example of fig2 a 2e the body cavities comprise calices of a kidney that are to be inspected for kidney stones although a kidney application is shown in the figures and is described in detail herein for purposes of example the systems and methods of this disclosure can be applied to other internal body cavities therefore the present disclosure is intended to cover applications beyond kidney inspection and stone removal beginning with fig2 a illustrated is the kidney 10 first described in relation to fig1 as is described above the kidney 10 comprises a plurality of calices 16 that may comprise kidney stones that are to be removed none visible in the view of fig2 a while the bodies of some of the calices 16 are visible in fig2 a only the openings of other calices are visible indicated by circles in fig2 a 2e as is illustrated in fig2 a an internal viewing device 30 has been inserted into the kidney 10 via the ureter 24 by way of example the viewing device 30 comprises a ureteroscope that has been inserted through a ureteral access sheath 32 that has been inserted into.