The best replacement for gastroscopy is endoscopy.

The best alternatives to gastroscopy are rated as following:
★★★★★  endoscopy
★★  egd
★  barium swallow
★  upper endoscopy
  barium meal

Your alternative for gastroscopy is not listed? Suggest!
Speaking about gastroscopy, one probably shouldn't forget about biopsy.

Other search terms related to gastroscopy and their ratings are:
★★★★★ biopsy
You have in mind a companion for gastroscopy and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of gastroscopy in all years. Click on graph for more.
gastroscopy
endoscopy
egd