Mammography tubes traditionally use a molybdenum anode target rather than tungsten. The principal advantage of the molybdenum target in breast imaging is:
- A It produces higher energy photons that penetrate dense breast tissue more easily
- B It reduces heat production at the anode, allowing shorter exposure times
- C It emits low energy characteristic X-rays around 17 to 19 keV, maximising subject contrast between glandular tissue and tumour ✓
- D It eliminates the need for breast compression during exposure
Correct answer: C. It emits low energy characteristic X-rays around 17 to 19 keV, maximising subject contrast between glandular tissue and tumour
Explanation
Mammography exploits small photoelectric effect differences between fat, glandular tissue and tumour, which are greatest at low photon energies. Molybdenum yields characteristic X-rays at approximately 17.9 and 19.6 keV, ideal for this purpose, and is usually paired with a molybdenum filter. Option A is wrong because high energies would abolish soft tissue contrast. Breast compression remains mandatory regardless of target material, mainly to reduce scatter, blur and dose.
Reference: Bushberg, Seibert, Leidholdt and Boone, The Essential Physics of Medical Imaging, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.