Shares of Shanghai United Imaging Healthcare Co. surged on its Shanghai market debut after the Chinese company raised 10.99 billion yuan ($1.61 billion) in the largest initial public offering. of the STAR market this year. Its stock gained as much as 75% on Monday morning and was last trading up 66% at CNY182.52, compared to its IPO price of CNY109.88 per share. That gives it a market capitalization of around 150 billion yuan, according to data provider Wind. The company, which makes medical imaging and radiation therapy equipment, said it would use proceeds from the offering to “fund its research…