Fig. 1. Basic principle of NIRST. (a) Schematic of NIRST; (b) light-breast tissue interaction; (c) absorption spectra of four main chromophores

Fig. 2. Schematic diagram of three measurement modes commonly used in NIRST. (a) CW; (b) FD; (c) TD

Fig. 3. Representative CW systems. (a) CW system developed by Hielscher’s research group^[31]; (b) CW system developed by PHILIPS company^[32]; (c) Comfortscan system developed by DOBI Global company^[34]

Fig. 4. Representative FD systems. (a) FD system developed by Paulsen’s research group^[35]; (b) FD system developed by Yodh’s research group^[36]

Fig. 5. TD system with 7 different wavelengths^[39]. (a) Experimental setup; (b) physical photo of system

Fig. 6. Hybrid FD-CW system. (a) System with 9 wavelengths^[44]; (b) system with 12 wavelengths^[46-47]; (c) system developed at University of Pennsylvania^[48]

Fig. 7. Multi-modality system for breast imaging. (a)(b)DBT/ NIRST system and interface detail^[56,63-64]; (c) dual-mode system that fuses ultrasound and NIRST and its probe detail^[61-62]

Fig. 8. Representative MRI/NIRST system and commonly used interface. (a) MRI/NIRST system with 9 wavelengths^[68]; (b) circular interface^[69]; (c) parallel board interface^[76]; (d) triangular interface^[68]; (e) strip interface^[77]

Fig. 9. Multimodal fusion method. (a) Comparison of different prior fusion methods^[75]; (b) experimental result of fusion of MRI and NIRST systems based on deep learning method^[82]

Fig. 10. Representative results of breast tumor diagnosis using multimodality NIRST system. (a) DBT/NIRST^[56]; (b) US/NIRST^[60]; (c) MRI/NIRST^[67]

Fig. 11. Efficacy monitoring of neoadjuvant chemotherapy utilizing NIRST system. (a) NAC prediction using NIRST system^[46];