Case 261

 We present a seventy four-year-old male for myelitis of right maxillary bone. Six years before, he had undergone radiation therapy for hypopharyngeal cancer whose size was approximately 3 cm in size,achieving complete response. Three years before, he was diagnosed bilateral maxillary bone necrosis probably due to adverse effect of radiation therapy. Thereafter, he underwent bone separation and plate insertion. However, osteomyelitis recurred. He was admitted in our hospital to receive re-bone separation and re-insertion of new plate. He had a habit of drinking spirit of 180 mL/day. He has suffered from diabetes mellitus and been given insulin for approximately 25 years. He took facial CT for further investigation (Figs. 1-3).

What is the tolerable dose of radiation for mandibular bone ?

1.　30Gy

2.　40Gy

3.　50Gy

4.　60Gy

answer

2022.3.22