What is pneumbra?
Fuzzy edges of shadow
What is the cause of penumbra?
Focal spot
What are the three factors that affect pneumbra and spatial resolution?
Focal spot x OID / SID
What is SOD if SID is 72” and OID is 3”?
72-3=SOD:69
Which end of the tube has the greater penumbra?
Cathode
Why/when do we fractionated focal spots?
Mag studies in interventional radiology
What effect does magnification have on spatial resolution?
Makes it fuzzy
How do we measure spatial resolution?
LP/MM (linepairspermillimeter)
What is the best way to control voluntary motions?
Communication
What is the best way to control involuntary motion?
change to large focal spot to cause fast exposure
What is the breathing technique?
Orthostatic breathing, patient breathes throughout long exposure to blur out ribs and lungs
Name four views we can utilize the breathing technique?
1)lateral t spine 2) RAO sternum 3) AP scapula 4) transthoracic humerus
If mag goes down what happens to resolution?
Resolution goes up
