Salivary gland functionScintigraphy in prediction of the salivary gland function after gland-sparing intensity modulated radiation therapy for head and neck cancer
Section snippets
Patients
The study population consists of 20 subjects diagnosed with head and neck cancer and treated using IMRT with an intention to spare the salivary gland function. Only patients with a good performance status (the World Health Organization, WHO, status 0 or 1) and scheduled to receive bilateral radiotherapy to the neck were entered to the study. The total quantitative saliva secretion was measured prior to initiation of therapy and 6 and 12 months after radiotherapy, and salivary gland scintigraphy
Results
The relative ejection fraction (rEF) as a function of the mean absorbed salivary gland radiation dose was modelled for the parotid and the submandibular glands (Fig. 2). A D50 value of approximately 39 Gy for the gland function was obtained from the fitted dose–response curves for the parotid and the submandibular glands both at 6 and 12 months after completion of radiotherapy. No statistically significant change in the gland function occurred between 6 and 12 months after therapy in the present
Discussion
The aim of the present study was to find a method for prediction of the residual salivary flow following salivary gland-sparing IMRT for head and neck cancer. We first determined the function of the major salivary glands preoperatively using salivary gland scintigraphy and calculated the relative saliva ejection fractions (rEFs, Eq. (1) and Fig. 1). We next fitted decay curves for the salivary gland rEF by longitudinal salivary gland scintigraphy examinations (Fig. 2). This allowed us to
Conclusions
Salivary gland scintigraphy is helpful for prediction of the salivary gland function following radiation therapy administered with a gland-spearing technique for head and neck cancer. We describe two models for estimation of the residual salivary gland function. In the average model, average proportions of saliva produced by each gland are estimated based on prior data obtained from a normal population. In the individual model post-treatment gland function is modelled using data from
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