Parametric oesophageal multiple swallow scintigraphy for validation of dysphageal symptoms during external beam irradiation of mediastinal tumours

The aim of the study was to evaluate dysphageal symptoms and to measure the effect of local analgesic treatment using parametric oesophageal multiple swallow scintigraphy (PES) during external beam irradiation of the mediasti nal region. Fifteen patients (most with lung cancer) with dysphagia grade I I underwent PES during external beam radiotherapy of the mediastinum before and after application of local analgesics. Dynamic parametric condensed im ages were recorded. The intensity of clinical symptoms was correlated with the emptying rate at 10 s (ER-10 s) and the mean transit time (MTT). Visual analysis of the images was performed and the results were correlated with the fields of irradiation portals. Of the 15 patients, 12 showed a correlat ion between irradiation portals and the region of oesophageal motility diso rder. Concordant results of clinical symptoms and PES data were found. In n ine patients with a decrease in dysphagia following local analgesia, an inc rease in mean ER-10 s and a decrease in MTT were observed. In three patient s with deterioration in clinical symptoms after analgesic treatment, a simi lar decrease in mean ER-10 s was found, though MTT remained constant. In th ree patients with normal values, motility disorders were detected in the dy namic study. In conclusion, PES was found to be a sensitive tool for the va lidation of dysphageal symptoms in patients during external beam irradiatio n of mediastinal tumours and for the evaluation and quantification of the e fficacy of local analgesic treatment. Additional visual analysis of the dyn amic study is helpful in diagnosing minimal disorders.