Old Jin had once experienced difficulties in a surgery involving the removal of foreign bodies, and later spent a lot of time researching the extraction of foreign objects. He brought out all the imaging related to foreign bodies since the establishment of Sanbo Hospital to study. He also reviewed all learning materials related to foreign bodies, and then designed various diagnostic and localization methods for foreign bodies, as well as various surgical techniques. Later, many hospitals facing difficult cases of foreign body extraction sent their patients to Sanbo Hospital. At that time, Song Zimo was learning from Old Jin about foreign body extraction, and he also became an expert in it.