What is PET-CT and SPECT-CT?

PET-CT (正子電腦斷層掃瞄)


  • 將PET圖像與CT圖像融合，可以明顯提高診斷的準確性、靈敏度及特異性。\
  • 價格偏高。
  • 有一定量的電離輻射（主要是CT的X線照射）。
  • SPECT-CT is where two different types of scans are taken and the images or pictures from each are fused or merged together. The fused scan can provide more precise information about how different parts of the body function and more clearly identify problems such as tumours (lumps) or Alzheimer’s disease, etc.
  • Single photon emission computed tomography (SPECT): SPECT images are obtained following an injection of a radiopharmaceutical that is used for nuclear medicine scans. The injected medication sticks to specific areas in the body, depending on what radiopharmaceutical is used and the type of scan being performed, for example. it will show bone for a bone scan, and gall bladder and bile ducts for a hepatobiliary scan.
  • The radiopharmaceutical is detected by a nuclear medicine gamma camera. The camera or cameras rotate over a 360 degree arc around the patient, allowing for reconstruction of an image in three dimensions.
  • Computed tomography (CT): CT images are obtained while you lie on a bed that moves into a ring, or “donut” shaped X-ray machine. Again, the X-ray machine rotates over a 360 degree arc around the patient, allowing for image reconstruction in three dimensions. The X-ray machine from the CT scanner rotates much faster than the gamma camera, so the CT part of the study takes less time than the SPECT study.
  • The similarity between SPECT and CT in the method of image processing allows the images to be combined. Combining the information from a nuclear medicine SPECT study and a CT study allows the information about function from the nuclear medicine study to be easily combined with the information about how the body structure “looks” in the CT study.



SPECT-CT

  • SPECT-CT imaging involves the acquisition of a low dose, non-contrast, non-diagnostic CT (computed tomography) scan immediately prior to SPECT (single photon emission computed tomography) imaging, which uses a rotating gamma camera. It is usually performed in nuclear medicine as an adjunct to standard single plane, gamma camera imaging as a useful problem solving tool for interpretation of difficult imaging.


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