Xenon-133 resorption in urinary bladder: functional diagnosis of bladder epithelium. 
The examination of resorption from the urinary bladder had previously been restricted almost exclusively to animal research, since, as a rule, a separation of the bladder from the urinary tract is required.  If this is not done, the resorbed test substance quickly finds its way back into the bladder.  More than 95 per cent of the xenon which has been resorbed from the bladder becomes eliminated through the lungs.  The detection and measurement of xenon in the exhaled air enables one to conduct, in a relatively simple fashion, urinary bladder resorption research using human subjects.  Studies based on 141 patients showed that the xenon exhalation tests currently represent the most sensitive and exact method for detecting and determining the nature of inflammatory diseases of the urinary bladder.  With a number of so-called "irritable bladder" cases it became clear that functional disorders of the bladder epithelium could be present without any evidence of associated morphologic changes.  With radiogenic treatment of tumors in the lower pelvic region one experiences an increase in bladder resorption with increased exposure to radiation.  There exists, as it were, a linear correlation between the radiation dosage and the degree of resorption from the urinary bladder.  Three months after terminating radiotherapy one can detect, as a rule, only a negligible increase in resorption.  If at this time the rate of xenon resorption still remains clearly high, one must reckon with permanent radiation damage of the bladder, insofar as it proves unsuccessful to eliminate the cause of cystitis.