Method and device of inspecting a fluorescent image of a mammal tissue and medical treatment device

An improved inspection method is disclosed herein to inspect a fluorescent image captured of a mammal tissue that has been rendered photosensitive with a fluorescent agent and irradiated with excitation light, the fluorescent image (FI) comprising an array of pixels having respective fluorescent signal values, the fluorescent signal values comprising a first number (N1) of fluorescent signal values representing the mammal tissue in the fluorescent image. The improved inspection method comprises determining (S6) a reference value (IR) such that a second number (N2) of fluorescent signal values comprised in the first number of fluorescent signal values is smaller than or equal to the reference value and the remainder of the first number of fluorescent signal values exceeds the reference value, which second number is a predetermined fraction of the first number; determining (S7) an average fluorescent signal value (μR) and a standard deviation (σR) of those fluorescent signal values comprised in the second number of fluorescent signal values; performing (S8) an image segmentation to distinguish in the fluorescent image (FI) a target region (TR) to denote a portion in the mammal tissue (MT) that is identified as tumorous tissue and a reference region (RR) to denote a remaining portion in the mammal tissue (MT), comprising determining per pixel (p) that it is part of the target region (TR) if a contrast to noise ratio CNR (p) for said pixel exceeds a predetermined threshold value (TCNR) and determining that the pixel is part of the reference region (RR) otherwise, wherein the contrast to noise ratio CNR (p) of a pixel is defined as in (I), wherein FI(p) is the fluorescent signal value of the pixel (p) and c is a predetermined constant; identifying (S9) at least one contour (B) of the target region (TR).