Mechanical evaluation of the dilation force of dilation devices during interventional endoscopic ultrasound oleh Takeshi Ogura, Saori Ueno, Akitoshi Hakoda, Atsushi Okuda, Nobu Nishioka, Jun Sakamoto, Masahiro Yamamura, Nobuhiro Hattori, Kimi Bessho, Hiroki Nishikawa, Rie Kanaoka, Youhei Kurose