A combination of a radionuclide transit test and a dynamic gastroesophageal scan was evaluated in normal volunteers, in patients with achalasia treated by pneumatic dilatation (n = 34) or Heller myotomy (n = 21). Interpretation of 31 of 57 examinations done with usual scintiscan was not possible because of too high esophageal tracer retention. Only one case could not be interpreted with the modified technique. Gastroesophageal reflux was detected and quantified in this manner in 8 patients, 6 more than with the usual scintiscan. 7 of these 8 patients have had Heller procedure, 1 patient even combined with fundoplasty.