updated 11/07/2013 AT 3:00 PM ET
•originally published 11/07/2013 AT 4:55 PM ET
Like Princess Diana before him, William is the president of the Royal Marsden NHS Foundation Trust – a patronage he took on in 2007. After witnessing two operations take place Thursday, he stepped out of the London hospital’s Chelsea location and, smiling, declared he felt “good – still standing!”
In images reminiscent of his late mother’s viewing of a heart operation in 1996, William, 31, scrubbed up and wore a surgical mask to see the experts at work.
While Diana witnessed a procedure for a 7-year-old boy with a hole in his heart, the Duke of Cambridge spent about 30 minutes in two operations – a breast reconstruction and a removal of a bladder tumor.
During the visit to the leading cancer hospital, he also met with staff, who showed him the latest radiotherapy technology, called CyberKnife.
A palace source tells PEOPLE William didn’t show any signs of fainting at the sight of the intricate operations and was “fascinated” by what he saw. A hospital spokeswoman says he was “calm and interested in the pioneering and innovative surgery.”