Mammography Physics Correctly Solved Exam |Question and Answer|

Mammography Physics Correctly Solved Exam |Question and Answer| Difference in attenuation of a breast cancer and regular breast tissue is very small. So, a lower energy and a nearly mono-energetic beam is needed to enhance the attenuation differences. Increased spatial resolution is required to see microcalcifications *Ans* Why is mammography different from plain diagnostic radiography? Because the photoelectric effect dominates at lower kVP. The ideal energy for mammo is between 16-23 keV. To get this energy, a voltage of 25-30 kVp is used(general Dx uses between 50-120) *Ans* Why low energy? molybdenum or rhodium . In general radiology, tungsten is used. This is because molybdenum and rhodum have a lower atomic number and generate lower K-characteristic x-rays *Ans* What target anodes are used in mammography? a k edge filter is placed outside of the tube with the goal of creating a nearly mono-energetic beam in the target range of 16-23 KeV. This filters both high and low photos with the benefit of removing the low energy photos which only give you dose and the high energy photons which won't have with contrast. *Ans* K edge filtration Higher *Ans* Rh anode/Rh filter is used for larger or denser breasts because it is __________ energy as compared to Mo anode/ Mo filter. Mo anode with Rhodium Filter *Ans* Which combination of anode and filter in mammography is used to give an intermediate energy? 0.3, 0.1 mm(general x-ray uses focal spots of 0.6 and 1.2 mm) This is because mammography requires a better spatial resolution *Ans* A focal spot of ____ and ____ mm is used in mammography because? Lower. mA is limited to 50 for 0.1 mm and 100 for 0.3 mm. *Ans* .Because of the smaller focal spot in mammography, the mA is _________ as compared to conventional radiography Longer *Ans* Because of the lower mA, a __________ exposure time is used in mammography. Chest wall. The loss of energy on the anode side(nipple side) is compensated for by angling the tube up about 20 degrees *Ans* The cathode side goes near the ______________ due to the heel effect. Beryllium; Pyrex Glass. *Ans* What type of exit window is used in mammography? In conventional radiography? Reduced thickness=less scatter=lower kVP can be chosen. Lower kVP and less scatter=improved contrast. Reduced thickness=less mAs needed=les