多种长焦区聚焦超声采集频率的人体甲状腺光声成像

Photoacoustic Imaging of Human Thyroid Based on Long-Focal-Zone Focused Transducers with Different Frequencies

临床上常规的超声成像对甲状腺结节进行诊断时存在误诊和漏诊。研究了利用多种采集频率的长焦区聚焦换能器进行光声成像的方法。在模拟样品里埋入不同尺寸的血块模拟病变组织,采用不同中心频率的换能器对模拟样品进行光声成像,然后将血液注入正常人体甲状腺内部形成两处瘀血区,模拟病变甲状腺组织,经二维扫描重构出模拟病变甲状腺组织的三维光声图像。结果表明,不同频率的超声换能器对不同尺寸病灶体的探测灵敏度存在较大差异,5MHz的宽带换能器对几百微米直至毫米量级大小的病灶体均具有良好的灵敏度。获得了甲状腺及其内部两处瘀血区域的较高分辨率和对比度的三维图像。此项技术有望与超声成像技术结合,进一步提高甲状腺疾病诊断的准确率。

There exist misdiagnosis and missed diagnosis with routine ultrasound imaging of thyroid nodules in present clinic.A novel method employing a series of long-focal-zone focused transducers with different frequencies for photoacoustic imaging（PAI） is presented.Some blood clots in different sizes are embedded in tissue-mimicking phantom to form a phantom containing specific pathological lesions.Transducers with different frequencies are used to image this phantom photoacoustically.Furthermore,blood is injected into normal human thyroid tissue,forming two blood stasis areas.Three-dimensional imaging is available by performing two-dimensional scanning through the tissue.We demonstrate that transducers with different frequencies have different sensitivities in detecting lesions of different sizes.The broadband transducer with a center frequency of 5 MHz has a better sensitivity in detecting lesions ranging from a few hundred microns to several millimeters.Therefore,a high resolution and excellent contrast three-dimensional image of the thyroid tissue with two blood stasis areas is obtained.This technique integrated with ultrasound imaging has the potential to increase the diagnostic accuracy in clinical thyroid nodule diagnosis.