| Subject: |
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Re: Exposure factors |
| Name: |
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Ana |
| Date Posted: |
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May 6, 08 - 8:50 PM |
| IP Address: |
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89.125.93.137 |
| Message: |
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KVp is your penetrating power, you need a higher KV to penetrate fibreglass (+4kV) or POP (+6/10 KV). Increasing the KVp also leeds to a more homogenous beam thus increasing the quality of the beam. KVp is also responsible for your contrast(ie.+KVp, +scatter,- contrast).Thus your contrast is reduced which is of no consequence as your'e mainly interested with boney detail in this particular case.
MAs is the quantity of your beam (ie.no. photons) & responsible for the amount of film blackening or density.(ie. +MAs, + density). In thick body parts such as an abdomen you need to visualise a range of diff densities & need an increased quantity of photons to display all the varying densities within. Hence density is increases & as KV is indirectly affected reduced contrast.
It's basically a balancing act when altering exposure factors as + KVp will - your MAs & achieving the level of penetration, contrast & density for the area under examination.
Hope this helps.  |
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