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9 Cards in this Set
- Front
- Back
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What are the fundamental principles of radiation protection during pediatric imaging?
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Justification (exam is indicated)
Utilization (The correct modality is used) Optimization: (correct parameters are used to balance dose and image quality) Optimize kVp and mA for pediatric sized patients One single phased scan is often enough Scan only the indicated area |
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What were the campaigns by the Alliance for Radiation safety in Pediatric imaging?
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1) Image gently: CT
2) Step Lightly: Interventional Fluoroscopy 3) General Fluoroscopy: Pause and Pulse 4) Nuclear medicine pediatric radiopharmaceutical doses 5) CR/DR radiography |
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Define CTDIvol and DLP
Does DLP represent a patient dose index? What is the utility? |
CTDIvol: [1/3 central dose + 2/3 surface dose]/ Pitch
DLP: CTDIvol x Scan Length No, it represents the energy depositied in a standard phantom DLP can tell you about the change in dose as you change imaging parameters |
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What does CTDIvol assume?
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That the patient is either the 16cm or 32cm diameter cylindrical plastic phantom.
CTDIvol underestimates the patient dose and misleads the radiologic technologist and radiologist if they assume CTDIvol represents the patient dose |
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If you use adult protocols on children, what is the dose penalty?
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you've given the child 3x as much radiation than the adult.
Taylor the study parameters based on the subject contrast of the organ in question. |
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What is the best way to reduce patient dose?
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decrease tube current or the rotation time
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Low kVp (improves/degrades) image contrast
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Improves image contrast and reduces dose but eventually leads to photon starvation and quantum mottle becomes a problem.
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What is SSDE?
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Size specific dose estimate
Converts CTDIvol estimates to more accurate child estimates (within 20%) with a correction factor based on patient size measurements or age. (still not ideal) |
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example: If CTDLvol for a scan = 5.5
Correction factor for a child is 2.29 what is the SSDE? |
SSDE = CTDIvol x correction factor
13 mGy. |
