A platform for gastric cancer screening in low- and middle-income countries

Abstract

Gastric cancer is the second leading cause of cancer death worldwide and screening programs have had a significant impact on reducing mortality. The majority of cases occur in low- and middle-income countries (LMIC), where endoscopy resources are traditionally limited. In this paper, we introduce a platform designed to enable inexpensive gastric screening to take place in remote areas of LMIC. The system consists of a swallowable endoscopic capsule connected to an external water distribution system by a multichannel soft tether. Pressurized water is ejected from the capsule to orient the view of the endoscopic camera. After completion of a cancer screening procedure, the outer shell of the capsule and the soft tether can be disposed, while the endoscopic camera is reclaimed without needing further reprocessing. The capsule, measuring 12 mm in diameter and 28 mm in length, is able to visualize the inside of the gastric cavity by combining waterjet actuation and the adjustment of the tether length. Experimental assessment was accomplished through a set of bench trials, ex vivo analysis, and in vivo feasibility validation. During the ex vivo trials, the platform was able to visualize the main landmarks that are typically observed during a gastric cancer screening procedure in less than 8 min. Given the compact footprint, the minimal cost of the disposable parts, and the possibility of running on relatively available and inexpensive resources, the proposed platform can potentially widen gastric cancer screening programs in LMIC.

Fig. 1

(a) The Hydrojet capsule inside a human stomach with gastric landmarks; (b) Labeled rendering of the Hydrojet capsule.

Fig. 2

(a) Exploded view of the Hydrojet capsule; (b) Orientation of Exhaust and Suction Ports; © Hydrojet capsule using water jet actuation in air.

Fig. 3

Block diagram of the Hydrojet system.

Fig. 4

The Hydrojet next to a standard gastroscope (Olympus Corp., Model: GIF180).

Fig. 5

Hydrojet estimated range of motion.

Fig. 6

Estimated angular orientation of the Hydrojet capsule as a function of tip actuation force at varying tether length, L. The vertical dashed lines represent the maximum tip actuation forces available in the current platform.

Fig. 7

Experimental Range of Motion: (a) Top View; (b) Side View.

Fig. 8

(a) External view of ex vivo setup with the laser source; (b) Internal view of laser beam from the Hydrojet camera.

Fig. 9

In vivo trials: (a-c) Three consecutive frames acquired by the retroflexed endoscope showing the Hydrojet in motion.