Recent reports on fluorescence spectroscopy techniques for skin cancer diagnosis.

S. no.	Signal used	Description	Merits	Demerits	Acc, Se, Sp	Ref.
1	300 nm	The tumours are differentiated by the fluorescence intensity	High sensitivity	Samples become darker if proper dying agent is not provided	—	133
2	442 nm	Fluorescent agent is employed to analyze the bio molecule distribution	Distribution of bio molecule can be analyzed easily	Applicable only for detecting non-melanoma	Se: 96.6%	134
3	360–600 nm	Fluorescence spectra is used to classify the tumors at the wavelength of 436 nm and 440 nm	Short excitation source is enough	Less feasible	—	135
4	630 nm	Suppression of cytokine production is recorded	Cytokine production can be analysed	Two common side effects of PDT are cutaneous photosensitization and systemic immunosuppression	Acc: 83%	136
5	442 nm	A non-invasive diagnostic tool to identify diseased tissue and normal tissue from the absorption property of the chromophores	High resolution	Need high and optimum level of instrumentation setup	—	137
6	410 nm	Laser-induced fluorescence spectroscopies are used to detect the skin cancer by in vivo methods without biopsy	Can able to differentiate the normal tissue from malignant tissue	Highly engaged to external noise that disturbs the measurement	—	138
7	300 nm for epidermal tryptophan and 330 to 400 nm for dermal collagen crosslink	The fluorescence intensity of dermal collagen is generally lower in tumour than in the normal tissues	Abnormality in malignancy condition can be estimated easily	It requires endogenous fluorescence for diagnosis	—	139
8	650–750 nm	The tumours can be detected by using a tunable light source along with CCD camera	Fluorophore can be retained between the normal and tumour cells	High cost	—	140
9	355 nm and 440 nm	Two ultrafast lasers were used at 355 nm that excites the auto fluorescence	High resolution	External probe is required	—	141
10	785 nm	From the images of the pigmented skin lesions, both the fluorescence and reflectance were studied	High sensitivity	Cost is high	—	142
11	292 nm for tryptophan and 377 nm for collagen	The sampling points for Raman spectroscopy were chosen by auto fluorescence segmentation. It's function is to diagnose the BCC in sampled tissue during the Mohs micrographic surgery which is much faster than frozen section histopathology	Classification of skin lesions can be made easy	Segmentation is required to analyse whether the surgery is needed or not	Se: 100%, Sp: 92%	143
12	400 and 2400 nm	Cancer tissue can be diagnosed by synchronous fluorescence (SF) imaging	Highly efficient	It is a weekly emitting component.	Se: 82–97%	144