CALCULATION APPARATUS AND CALCULATION METHODAbstract[Abstract][Object] To provide a calculation apparatus and acalculation method capable of calculatingpharmaceutical concentration in a tissue in real time. [Solving Means] A photodynamic therapy apparatus 1 as a calculation apparatus is an apparatus forirradiating a tissue having absorbed photo-sensitivepharmaceutical, the photo-sensitive pharmaceutical absorbing an excitation light and emitting fluorescence, with the excitation light emitted from a tip portion ofa laser catheter 300, including a connector 210, alight source 110, and a light detection unit 130. The laser catheter 300 is capable of beingattached/detached to/from the connector 210. The light source 110 outputs the excitation light to the laser catheter 300 via the connector 210. The light detectionunit 130 detects intensity of the fluorescence, the fluorescence being entered from the laser catheter 300 via the connector 210, to calculate concentration of the photo-sensitive pharmaceutical in a tissue, the tipportion of the laser catheter 300 contacting the tissue.Fig. 3
