CT扫描vs PET扫描
计算机断层扫描,简称CT扫描用X射线得到轴向膜。这与普通的x光片不同,因为它可以提供更多关于组织的细节。x射线从一侧通过,传感器将捕捉来自另一侧的射线。这将发生在身体周围。探头可以做圆周运动,360度曝光有助于获得清晰的图像。计算机将根据辐射计算并给出组织的视图。在CT中,辐射是通过X射线从外部发出的。
PET扫描是正电子发射断层扫描的缩写形式.核反应时释放正电子。正电子的重量与电子相似,但带正电。PET扫描中使用的同位素(原子可以分裂并发射射线)。通常使用FDG(氟脱氧葡萄糖)。它会发射正电子。通常放射性的FDA会被活性组织吸收。FDA就像葡萄糖。葡萄糖是为组织提供能量的燃料。葡萄糖会被活性组织吸收。 Same way FDG is also taken by the metabolically active tissue. So the radioactive substance [example: isotopes with short half lives such as carbon-11 (~20 min), nitrogen-13 (~10 min), oxygen-15 (~2 min), and fluorine-18 (~110 min)] will attach to the glucose. When the glucose is taken by the tissue the radioactive substance is also taken inside the tissue. The amount of uptake will help us to identify the activity of the tissue. According to the amount taken by the tissue, the emission amount varies. The positrons will react with the electrons in the tissue. Electron is a negative charged particle and positron is a positive charged particle. This reaction will be calculated by the computer and the final image will be given by the computer. PET scan is useful to find out the spread of the cancer. The cancer tissue usually divides very quickly, in other words they are ACTIVE. So they will take more glucose from the blood.
PET扫描比CT扫描需要更多的时间。因为从注射到组织吸收葡萄糖需要等待一段时间。通常时间间隔接近一个小时。
PET扫描可与CT扫描或MRI扫描结合使用。
总之, CT和PET扫描是医学专业人员使用的成像技术。 两者都有助于发现癌症的扩散。 两者都会增加患癌症的风险,因为它们都在使用辐射。 PET扫描优于CT,因为它能给出组织的代谢活性。 PET扫描比普通CT需要更多的时间。 PET扫描使用放射性同位素,释放辐射,但CT使用x射线。 CT比PET扫描相对简单 |
留下一个回复