Figure 1.

Representative case of mucoepidermoid carcinoma treated with carbon‐ion radiotherapy. (a) A 51‐year‐old female with T3N0M0 mucoepidermoid carcinoma. The MRI showed a 40‐mm gadolinium‐enhanced tumor located in the deep lobe of the parotid gland with extraparenchymal extension. The patient refused surgery and elected to receive carbon‐ion radiotherapy. (b) Carbon‐ion radiotherapy was carried out with 64 Gy (relative biological effectiveness) in 16 fractions. The gross tumor volume is represented by the red outline. (c) On repeat MRI performed 3 years after carbon‐ion radiotherapy, no enhancing lesions were detected. No distant or lymph node metastases were detected during follow‐up. There were no late adverse events of grade 2 or higher.