3D wide‐field multispectral photoacoustic imaging of human melanomas in vivo: a pilot study

Abstract

Background The Breslow depth is an important parameter to determine the excision margin and prognosis of melanoma. However, it is difficult to accurately determine the actual Breslow depth before surgery using the existing ocular micrometer and biopsy technique. Objectives To evaluate the use of 3D wide‐field multispectral photoacoustic imaging to non‐invasively measure depth and outline the boundary of melanomas for optimal surgical margin selection. Methods Six melanoma patients were examined in vivo using the 3D multispectral photoacoustic imaging system. For five cases of melanomas (one in situ, three nodular, and one acral lentiginous type melanoma), the spectrally unmixed photoacoustic depths were calculated and compared against histopathological depths. Results Spectrally unmixed photoacoustic depths and histopathological depths match well within a mean absolute error of 0.36 mm. In particular, the measured minimum and maximum depths in the in situ and nodular type of melanoma were 0.6 and 9.1 mm, respectively. In the 3D photoacoustic image of one metastatic melanoma, feeding vessels were visualized in the melanoma, suggesting the neovascularization around the tumour. Conclusions The 3D multispectral photoacoustic imaging not only provides well‐measured depth and sizes of various types of melanomas, it also visualizes the metastatic type of melanoma. Obtaining accurate depth and boundary information of melanoma before surgery would play a useful role in the complete excision of melanoma during surgery.

Review on Optical Imaging Techniques for Multispectral Analysis of Nanomaterials

“…Similar to the optical imaging techniques, multiple wavelengths of the excitation beams are used for multispectral analysis in PAI. Due to its relatively deep imaging depth, PAI has been applied to clinical studies [26][27][28][29] of breast cancers [30][31][32], thyroid cancers [33][34][35][36], prostate cancer [37], and melanoma [38,39], as well as small animal studies [40][41][42][43].…”

Seeing through the Skin: Photoacoustic Tomography of Skin Vasculature and Beyond

“…Dual-wavelength imaging has also been performed on humans using the commercial PAT system Vevo Lazr (Breathnach, 2015). Park et al demonstrated success in identifying the depths of in situ and nodular melanoma as well as surrounding neovascularization in six patients in vivo using a 3D multispectral PA imaging system (Park et al, 2021b). As of late, melanoma diagnosis has even seen further advancement through the development of handheld PAT systems (Figs.…”

High-speed photoacoustic microscopy: A review dedicated on light sources

“…The PACT typically uses multi-element US transducers with various geometries such as linear [ [17] , [18] , [19] ], arc [ [20] , [21] , [22] ], hemisphere [ [23] , [24] , [25] ], or planar [ 26 ] array to obtain tomographic or cross-sectional images. The PACT systems take advantages of real-time imaging capability (typically 5–20 Hz) and deep imaging depth (up to ∼5 cm) and have been used for several clinical applications [ [27] , [28] , [29] , [30] , [31] , [32] , [33] ], such as breast [ [34] , [35] , [36] ], prostate [ [37] , [38] , [39] ], thyroid [ 40 , 41 ], and melanoma [ 42 , 43 ]. In addition to the human clinical applications, PACT systems also have been applied to small animal studies, including brain imaging [ 44 ], whole-body dynamics monitoring [ 45 ], and deep-tissue imaging [ 46 ].…”