Fig. 1.

(a) NIRx NIRSport2¹⁴ (NIRx Medizintechnik GmbH, Germany). Reproduced with permission, courtesy of Bio Optical and Acoustic Spectroscopy Lab, Boston, Massachusetts, USA. (b) Artinis Brite system. Reproduced with permission, courtesy of Artinis Medical Systems, Elst, The Netherlands. (c) In-house continuous-wave (CW) HD-DOT system.⁷ Reproduced with permission, courtesy of Nature Portfolio. (d) Light weight fiber-based CW HD-DOT device.¹⁵ Reproduced with permission, courtesy of SPIE. (e) Portable fiber-based CW HD-DOT system.¹⁶ Reproduced with permission, courtesy of Elsevier.