Current gradient-index(GRIN)lens based proximal-driven intracoronary optical coherence tomography(ICOCT)probes consist of a spacer and a GRIN lens with large gradient constant.This design provides great flexibility to...Current gradient-index(GRIN)lens based proximal-driven intracoronary optical coherence tomography(ICOCT)probes consist of a spacer and a GRIN lens with large gradient constant.This design provides great flexibility to control beam profiles,but the spacer length should be well controlled to obtain desired beam profiles and thus it sets an obstacle in mass catheter fabrication.Besides,although GRIN lens with large gradient constant can provide tight focus spot,it has short depth of focus and fast-expanded beam which leads to poor lateral resolution for deep tissue.In this paper,a type of spacer-removed probe is demonstrated with a small gradient constant GRIN lens.This design simplifies the fabrica-tion process and is suitable for mass production.The output beam of the catheter is a narrow nearly collimated light beam,referred to as pencil beam here.The full width at half maximum beam size varies from 35.1μm to 75.3μm in air over 3-mm range.Probe design principles are elaborated with probe/catheter fabrication and performance test.The in vivo imaging of the catheter was verified by a clinical ICOCT system.Those results prove that this novel pencil-beam scanning catheter is potentially a good choice for ICOCT systems.展开更多
Water plays a vital role in biological metabolism and it would be essential to trace the water content non-invasively,such as leveraging the vibrational absorption peak of the O-H bond.However,due to the lack of an ef...Water plays a vital role in biological metabolism and it would be essential to trace the water content non-invasively,such as leveraging the vibrational absorption peak of the O-H bond.However,due to the lack of an efficient laser source,it was challenging to image the water content in the deep tissue with micron-level spatial resolution.To address this problem,we develop a high-power hybrid optical parametrically-oscillating emitter(HOPE)at 1930 nm,at which the vibrational absorption peak of the O-H bond locates.The maximum pulse energy is over 1.74μJ with a pulse repetition rate of 50 kHz and a pulse width of 15 ns.We employ this laser source in the optical-resolution photoacoustic microscopy(OR-PAM)system to image the water content in the phantom and the biological tissue in vitro.Our 1930-nm OR-PAM could map the water content in the complex tissue environment at high spatial resolution,deep penetration depth,improved sensitivity,and suppressed artifact signal of the lipid.展开更多
基金financial supports from the National Natural Science Foundation of China(Grant No.81927805)Shenzhen Municipal Science and Technology Plan Project,China(Grant No.JCYJ20160427183803458)。
文摘Current gradient-index(GRIN)lens based proximal-driven intracoronary optical coherence tomography(ICOCT)probes consist of a spacer and a GRIN lens with large gradient constant.This design provides great flexibility to control beam profiles,but the spacer length should be well controlled to obtain desired beam profiles and thus it sets an obstacle in mass catheter fabrication.Besides,although GRIN lens with large gradient constant can provide tight focus spot,it has short depth of focus and fast-expanded beam which leads to poor lateral resolution for deep tissue.In this paper,a type of spacer-removed probe is demonstrated with a small gradient constant GRIN lens.This design simplifies the fabrica-tion process and is suitable for mass production.The output beam of the catheter is a narrow nearly collimated light beam,referred to as pencil beam here.The full width at half maximum beam size varies from 35.1μm to 75.3μm in air over 3-mm range.Probe design principles are elaborated with probe/catheter fabrication and performance test.The in vivo imaging of the catheter was verified by a clinical ICOCT system.Those results prove that this novel pencil-beam scanning catheter is potentially a good choice for ICOCT systems.
基金This project is funded by Research Grants Council of the Hong Kong Special Administrative Region,China(HKU 17200219,HKU 17209018,E-HKU701/17,CityU T42-103/16-N,and HKU C7047-16G)Natural Science Foundation of China(N_HKU712/16)。
文摘Water plays a vital role in biological metabolism and it would be essential to trace the water content non-invasively,such as leveraging the vibrational absorption peak of the O-H bond.However,due to the lack of an efficient laser source,it was challenging to image the water content in the deep tissue with micron-level spatial resolution.To address this problem,we develop a high-power hybrid optical parametrically-oscillating emitter(HOPE)at 1930 nm,at which the vibrational absorption peak of the O-H bond locates.The maximum pulse energy is over 1.74μJ with a pulse repetition rate of 50 kHz and a pulse width of 15 ns.We employ this laser source in the optical-resolution photoacoustic microscopy(OR-PAM)system to image the water content in the phantom and the biological tissue in vitro.Our 1930-nm OR-PAM could map the water content in the complex tissue environment at high spatial resolution,deep penetration depth,improved sensitivity,and suppressed artifact signal of the lipid.
