The study involves patients diagnosed with head and neck squamous cell carcinoma who will receive a single injection of botulinum toxin type A into the salivary glands before undergoing radiation treatment. The goal is to see whether this injection can protect the salivary gland from damage that often leads to a dry mouth condition known as xerostomia. The injection is given a short time before the cancer‑directed radiation, and participants will be asked to complete a few simple questionnaires and undergo routine check‑ups during and after the treatment period.
During the study, participants will have a baseline assessment of how well their salivary glands work, using a special imaging test called scintigraphy and a simple saliva‑collection test. After the radiation course, the same tests are repeated to compare any changes. An additional scan using ultrasound will look at the size and texture of the glands, and questionnaires will evaluate any feelings of dry mouth and overall quality of life. Safety will be monitored by recording any side effects or problems at the injection site.
Czechia 
