Successful therapy of twin‐to‐twin transfusion syndrome requires accurate imaging to guide laser photocoagulation of the anastomosing placental vessels. Photoacoustic (PA) imaging is an alternative imaging method that provides contrast for hemoglobin, and in this study, it was used to visualize chorionic superficial and subsurface vasculature in human placentas. The strong potential of PA imaging to guide minimally invasive fetal therapies was demonstrated. Further details can be found in the article by Efthymios Maneas, Rosalind Aughwane, Nam Huynh, et al. ( e201900167 ).
A comparative analysis of intrinsic skin aging between Caucasian and Asian subjects by slide‐free in vivo harmonic generation microscopy is reported. The cellular and nuclear areas of basal cells in Caucasians and Asians are found to increase at the same rate, ideal for scoring age. On the other hand, the viable epidermis thickness, the dermal papilla volume and height in Caucasians are found to decrease faster than those in Asians. Further details can be found in the article by Kuan‐Hung Lin, Yi‐Hua Liao, Ming‐Liang Wei, and Chi‐Kuang Sun ( e201960063 ).
An optical fan was demonstrated to screen leukemia cells from the blood sample at the single‐cell level in a noninvasive and noncontact manner. Further details can be found in the article by Xiaoshuai Liu, Yuchao Li, Xiaohao Xu, Yao Zhang, Baojun Li ( e201900155 ).
Optical Coherence Tomography angiography (OCTA) is widely used to image chorioretinal vasculature, with contrast that derives from scattering and motion of red blood cells (RBCs). In the rat eye, a scattering tracer highlights vertical vessels which are not visualized by intrinsic RBC scattering alone. The dependence of microvessel OCTA on angular orientation, explored in this work, represents a potential artifact that should be considered in the clinical interpretation of OCTA. Further details can be found in the article by Jun Zhu, Marcel T. Bernucci, Conrad W. Merkle, and Vivek J. Srinivasan ( e202000090) .
A type of compact and cost‐effective light‐sheet imaging device, termed sub‐voxel‐resolving light‐sheet add‐on module (SLAM), is developed to cooperate with conventional 2D epifluorescence microscope, allowing high‐contrast, resolution‐improved 3D imaging of various biological samples at high throughput. Further details can be found in the article by Fang Zhao, Yicong Yang, Yi Li, et al. ( e201960243 ).
The detection of colon cancer by using Poincaré sphere and 2D polarimetric imaging approach. Further details can be found in the article by Deyan Ivanov, Viktor Dremin, Alexander Bykov, Ekaterina Borisova, et al. ( e202000082 ).
Infrared spectroscopy enables insight into light‐activated riboflavin‐induced collagen cross‐linking for future intervertebral disc treatment and repair. Further details can be found in the article by Ioannis Vasilikos, Julian Haas, Graciosa Q. Teixeira, Julia Nothelfer, Cornelia Neidlinger‐Wilke, Hans‐Joachim Wilke, Andreas Seitz, Demetrios G. Vavvas, Josef Zentner, Jürgen Beck, Ulrich Hubbe, and Boris Mizaikoff ( e202000110 ).
A high‐efficiency computer‐aided diagnostic model of ovarian cancer was developed, integrating SHG imaging technology for non‐invasive imaging of living tissue and machine learning method based on radiomics and TPOT. This model can rapidly, non‐destructively, and accurately perform ovarian cancer diagnosis and has great potential in improving diagnostic efficacy and efficiency of medical pathologists. Further details can be found in the article by Guangxing Wang, Yang Sun, Youting Chen, Qiqi Gao, Dongqing Peng, Hongxin Lin, Zhenlin Zhan, Zhiyi Liu, and Shuangmu Zhuo ( e202000050 ).
The first post-pandemic face-to-face international conference in Biophotonics took place in Porto in April 2022. High quality and inspiring presentations have been delivered by leading scientists and internationally recognized professionals, standing on the forefront of Biophotonics research and representing broadness of the field. A selected number of these presentations resulted in the papers that are presented in this special issue. The cover images were selected from Hoffer et al., Lomanovskaya et al., Li et al., and Burton et al. (clockwise).
A novel 0.9 mm-diameter intravascular photoacoustic catheter with coaxial excitation and detection was developed to overcome the limitation of imaging range. A miniature ring-shaped ultrasound transducer with a 0.18 mm-diameter orifice in the center was successfully fabricated. The results demonstrated that the coaxial catheter exhibited much better photoacoustic/ultrasound imaging performance from the intima to the adventitia. Further details can be found in the article by Riqiang Lin, Qi Zhang, Shengmiao Lv, Jiaming Zhang, Xiatian Wang, Dongliang Shi, Xiaojing Gong, and Kwok-ho La ( e202200269 ).
A new high‐speed cellular imaging method using clinically applicable moxifloxacin labeling, called as moxifloxacin based confocal microscopy (MBCM), was developed for fast and sensitive tumor detection and delineation. The MBCM demarcated malignant brain tumor from normal brain by visualizing dense and irregular cell distribution in the tumor. An image processing algorithm was developed for automated brain tumor detection. Further details can be found in the article by Seunghun Lee, Won Yeong Park, Hoonchul Chang, et al. ( e201900197 ).
A 3D printed stereotaxic head mount that enables high resolution imaging of the anterior chamber of the eye in alert and freely mobile mice is designed in this study. The system is placed non‐invasively using temporal mount bars and a snout mount, without breaking the skin or risking suffocation, while an endoscopic channel stabilizes the ocular probes. Further details can be found in the article by Bjorn Paulson, Sangwook Lee, Miyeon Jue, Kyungsung Lee, Sanghwa Lee, Guk Bae Kim, Youngjin Moon, Joo Yong Lee, Namkug Kim, and Jun Ki Kim ( e201960188 ).
Transcranial photobiomodulation (tPBM) with wavelength at 808 nm was applied to a rat model of acute seizures. The tPBM successfully attenuated convulsive status epilepticus, and the tPBM was shown to reduce the apoptosis of parvalbumin‐positive interneurons (PV‐INs) and preserved the integrity of perisomatic inhibitory network of PV‐INs to principle cells in the hippocampus. Further details can be found in the article by Chung‐Min Tsai, Shwu‐Fen Chang, and Hsi Chang ( e202000095 ).
A novel volumetric information fusion based on joint weighted evaluation and stationary wavelet transform is proposed. Threedimensional stationary wavelet transform was performed on multi-focus data to obtain wavelet coefficients. Differential evolution based on joint weighted evaluation was then employed to optimize the block size of division. Corresponding sub-coefficients of multi-focus data were fused with the proposed fusion rule. Finally, large volumetric and high-resolution photoacoustic imaging can be achieved by applying the inverse stationary wavelet transform. Further details can be found in the article by Xianlin Song, Sihang Li, Zhuangzhuang Wang, and| Xiongjun Cao ( e202200234 )
A dual‐raster‐scanned photoacoustic microscope (DRS‐PAM) was reported, which integrates a two‐dimensional motorized translation stage for large field‐of‐view imaging and a two‐axis fast galvanometer scanner for real‐time imaging. The DRS‐PAM provides a flexible transition from wide‐field monitoring the vasculature of organs to real‐time imaging of local dynamics. Further details can be found in the article by Fei Yang, Zhiyang Wang, Wuyu Zhang, et al. ( e202000022 ).
Intraoperative neurosurgical diagnosis of brain tumor determines the success rate of patients' prognoses. We firstly proposed a novel approach based on an optical method to distinguish the site of the tumor functionally. The promoted technique is non‐invasive, non‐radioactive, dye‐free, and potential of real‐time monitoring, which is still not available nowadays by using other techniques. The method could be applied to neuroimage guiding system for precision surgery of brain. Further details can be found in the article by Xin‐Rui Liu, Tien‐Yu Hsiao, Yun‐Qian, et al. ( e201900200 ).
Top: Illustration of how to obtain 3D embryo images from a locust egg using OCT B‐scans. The internal structures of the embryo can be clearly identified as it develops. Bottom: The real time observation of katatrepsis and twist of a lowland locust embryo on days 7‐8, as the embryo develops. The embryonic movements can be readily identified by tracking the positions of the embryo's eyes (E1 and E2). Further details can be found in the article by Ya Su, Liya Wei, Hao Tan, et al. ( e201960047 ).
A false‐colored and merged image of fresh, ex vivo rat kidney acquired using an excitation‐scanning hyperspectral imaging system. The spectral image was acquired using excitation wavelengths from 360 to 550 nm. Colors represent principal components extracted from a spectral image cube featuring no added labels or markers. Further details can be found in the article by Peter F. Favreau, Joshua A. Deal, Bradley Harris, et al. ( e201900183 ).
This study presents a novel intraoperative in vivo imaging approach which harnessed Cerenkov luminescence (CL) to detect primary and metastatic colorectal cancer (CRC) using clinically approved radiopharmaceuticals. In the mice and swine experiments, the proposed approach effectively improved the effect of CRC surgery. The approach is believed to be promising for utilizing CL in open surgery. Further details can be found in the article by Zeyu Zhang, Yawei Qu, Yu Cao et al. ( e201960152 )
