Does salivary gland scintigraphy predict response to pilocarpine in patients with post-radiotherapy xerostomia?

This study was undertaken to determine whether standard salivary gland scin tigraphy may be used for the objective assessment of salivary gland sialogo gues, in particular oral pilocarpine, in the treatment of post-radiotherapy xerostomia. Nine patients, with xerostomia following radiotherapy to the h ead and neck region underwent salivary,oland scintigraphy with technetium-9 9m pertechnetate (40 MBq) both before and following 1 month of oral pilocar pine (5 mg tds). For each scan, the percentage uptake in the first 14 min, the peak uptake, time to peak uptake and the percentage of activity excrete d following lemon juice stimulation were calculated. The results were corre lated with the subjective response as assessed by questionnaire and visual analogue scale. We found no correlation between subjective response and any of the four scan parameters analysed. We could nor identify any parameter that predicted those patients who would respond to pilocarpine. In addition , only one parameter, the percentage of activity excreted following stimula tion, correlated with previous dose of radiotherapy to the gland. In conclu sion, in this study salivary gland scintigraphy did not appear to correlate with or predict response to oral pilocarpine. However, future studies migh t consider performing salivary gland scintigraphy prior to radiotherapy as well as at differing time points following the commencement of pilocarpine.