<unk>  means looking inside and typically refers to looking inside the human body for medical reasons using an instrument called an<unk> .<unk>  can also refer to using a borescope in technical situations where direct line-of-sight observation is not feasible.<unk>  is a minimally invasive diagnostic medical procedure that is used to assess the interior surfaces of an organ by inserting a tube into the body.  The instrument may have a rigid or flexible tube and not only provide an image for visual inspection and photography, but also<unk> able taking biopsies and retrieval of foreign objects.<unk>  is the vehicle for minimally invasive surgery.
Many<unk> c procedures are considered to be relatively painless and, at worst, associated with mild discomfort.  Most patients tolerate the procedure with only topical anaesthesia of the oropharynx using lignocaine spray (Source: Esophagogastroduodenoscopy, Wikipedia).  Complications are rare (only 5% of all operations) but can include perforation of the organ under inspection with the<unk>  or biopsy instrument.  If that occurs open surgery may be required to repair the injury.
Endoscopy
Dysphagia endoscopy
Achalasia ultrasound
Dysphagia CT
Achalasia CT
Gastric suction
Esophageal endoscopic ultrasound
Achalasia x ray