Dynamic magnetic resonance spectroscopy study on radiation-induced temporal lobe injury in the elderly during radiotherapy / 中华老年医学杂志

ABSTRACT

Objective To study the metabolic characteristics of temporal lobe injury during the radiotherapy in the elderly with nasopharyngeal carcinoma through 1H- magnetic resonance spectroscopy (MRS). Methods The 15 aged and 23 young cases among 80 cases with nasopharyngeal carcinoma confirmed clinically and receiving radiotherapy for the first time were involved in the same period of July 2006 to May 2009. Conventional MRI scanning and bilateral temporal MRS were performed before and during radiotherapy at radiation dosages of 20 Gy, 40 Gy, and 60 Gy respectively. The spectroscopy morphology and the ratios of the three main metabolites were compared and analyzed. Results The values of N-acetylasparate (NAA)/creatine (Cr) was lower and choline-containing compound (Cho)/Cr ratio was higher in aged group than in young group before radiotherapy (P＞0.05). The spectroscopy morphology stepped down, NAA, Cho, NAA/Cr, Cho/Cr and NAA/Cho decreased to some extent along with the adding of radiation dosages in the course of radiotherapy. At the end of radiotherapy, the decreased amplitude of NAA/Cr value was larger in aged group than in control group (P＜0.01), and the amplitude of Cho/Cr value was lower than other group. Conclusions The neurons of aged patients with nasopharyngeal carcinoma have a weak tolerance to the radiation, brain injury occurs earlier and heavier in aged patients than in young patients. It is necessary to prevent neuron injury early.