and so one could take a three dimensional image of the whole body.

所以你能得到整个身体的三维影像
Now, because you're just using line sources of radiation

因为你现在在使用线辐射源
one can reduce the amount of radiation

相比单一的X线片而言
that with each individual picture that you take compared to an X-ray.

可以减少辐射量
But you've got to take a lot of these pictures,

但由于你拍摄了许多张X光片
and so the cumulative dose of radiation can be significant.

所以累积的辐射量可以非常巨大
Even though you could take a full three dimensional of your body,

所以即使CT能提供全身的三维影像
you might not want to do that.

你可能也不想去做全身CT
You might just want to take a picture of the slices

你可能只想做你感兴趣部位的断层扫描
that seem to be of interest, maybe the abdomen,

比如腹部
maybe the chest, maybe the knee

也许是胸部也许是膝盖
if you're having a problem with your knee.

如果你膝盖有毛病的话