Performance evaluation of endoscopic Cerenkov luminescence imaging system: in vitro and pseudotumor studies

Abstract

By integrating the clinically used endoscope with the emerging Cerenkov luminescence imaging (CLI) technology, a new endoscopic Cerenkov luminescence imaging (ECLI) system was developed. The aim is to demonstrate the potential of translating CLI to clinical studies of gastrointestinal (GI) tract diseases. We systematically evaluated the feasibility and performance of the developed ECLI system with a series of in vitro and pseudotumor experiments. The ECLI system is comprised of an electron multiplying charge coupled device (EMCCD) camera coupled with a clinically used endoscope via an optical adapter. A 1951-USAF test board was used to measure the white-light lateral resolution, while a homemade test chart filled with 68 Ga was employed to measure the CL lateral resolution. Both in vitro and pseudotumor experiments were conducted to obtain the sensitivity of the ECLI system. The results were validated with that of CLI using EMCCD only, and the relative attenuation ratio of the ECLI system was calculated. Results showed that The white-light lateral resolution of the ECLI system was 198 µm, and the luminescent lateral resolution was better than 1 mm. Sensitivity experiments showed a theoretical sensitivity of 0.186 / KBq l μ ( ) for the in vitro and pseudotumor studies, respectively. The relative attenuation ratio of ECLI to CLI was about 96%. The luminescent lateral resolution of the ECLI system was comparable with that of positron emission tomography (PET). The pseudotumor study illustrated the feasibility and applicability of the ECLI system in living organisms, indicating the potential for translating the CLI technology to the clinic.

Review of biomedical Čerenkov luminescence imaging applications

“…It has been shown that, it is possible to detect the organs within the body by using optical fibers and a CCD camera [54], as well as enable endoscopic testing [55,56]. These studies led to introduction of CLE systems which have apparently high sensitivity and resolution and consist of an optical fiber connect to a CCD sensitive camera which can be used as a helpful tool during the cancer surgery [16] (Fig.…”

Sensitivity improvement of Cerenkov luminescence endoscope with terbium doped Gd2O2S nanoparticles

“…Due to a small aperture of endoscope and transmission attenuation of optical fibers, there is great attenuation for the CLE system, resulting in relatively low detection sensitivity of radiotracers. 9 There are three possible ways to improve the detection sensitivity of the CLE system. One is to develop a fiber endoscope with an enlarged aperture.…”

“…13 The radiotracer and CLE system used here are the same as in our previous study. 9 The radionuclide 68 Ga is in the form of 68 produced by a 68 Ge-68 Ga generator (ITG Isotope technologies Garching GmbH, Germany). The CLE system is a seamless combination of an electron multiplying CCD (EMCCD) camera (iXon3 888, Andor), an optical adaptor (Outai Corp), and a fiber endoscope (GIF-XQ40, Olympus), which is used to collect the emitted luminescence from the mixture of 68 Ga and Gd 2 O 2 S:Tb.…”

“…The two EP tubes were put into the field of view of the CLI system that is configured by an EMCCD camera coupled with a focus lens as well as a light-tight box, as the same one used in our previous study. 9 The white-light image was first taken with an exposure time of 1 s, as shown in Fig. 1(a), which intuitively presented the position of two EP tubes.…”

“…The pseudotumor mouse model was prepared according to the procedures described in our previous study. 9 Animal care and protocols were approved by the Fourth Military Medical University Animal Studies Committee. All animal operations were performed under general anesthesia by inhalation of 1%-2% isoflurane-oxygen.…”