Ultrasonic Tissue Characterization Quantitative Analysis Of Tissue Fibrosis Following Radiation Therapy

Purpose: To investigate the clinical utility of quantitative measurement of post-irradiation neck fibrosis by ultrasonic tissue characterzation(UTC) for patients with head and neck tumors.Materials and Methods: Forty patients with head and neck tumors receiving radical radiation therapy were included. We measured the maximum, minimum and mean values of ultrasound grayscale in the bilateral supraclavicular and upper-middle part of sternocleidomastoid muscle areas using quantitative analysis device at the time of prior radiation, 2 month and 6 month of post-radiations, respectively. The differences between the values were assessed by statistic chi-square test.Results: The mean grayscale values in the bilateral supraclavicular and upper-middle part of sternocleidomastoid muscle areas were 30.31±0.52, 30.27±0.80, 31.08±0.84, 31.30±2.28, 46.41±10.49, 44.17±9.16, 42.95±5.23, 42.19±5.47, 66.80±25.91, 58.48±21.545, 54.414±12.95, 54.61±12.95 at the time of prior radiation, 2 month and 6 month of post-radiations, respectively. The mean grayscale value in the region receiving 46Gy radiation therapy were 42.489±6.891, 41.15±7.064, 42.35±5.26, 42.19±5.46,53.39±12.98, 55.35±14.06, 54.45±12.95, 54.60±12.95, respectively, while those in the upper-middle part of sternocleidomastoid muscle areas receiving 66Gy radiation therapy were 50.34±12.08, 49.20±10.22, 77.50±30.78, 77.44±28.01, respectively. The severer the fibrosis was, the higher the mean grayscale value was.Conclusions: Post-irradiation fibrosis can be measured by the grayscale values using ultrasonic tissue characterzation(UTC). The degree of fibrosis has a positive correlation with time and dose of radiation. The severer the fibrosis is, the higher the mean grayscale value could be.UTC is a simple, sensitive, quantitative method without traumatism. It make up for the deficiency that other methods can't make quantitative analysis. And also it can provide clinic doctors one of the best methods of quantitative analysis on the tissue fibrosis of neck.