Niobium filter v. an aluminum filter.
Stirling
G C
GC
Holloway
A F
AF
D000535:Aluminum; D005374:Filtration; D006801:Humans; D009556:Niobium; D011829:Radiation Dosage; D011837:Radiation-Protective Agents; D011861:Radiography, Dental / Q000295:instrumentation*
D011837:Radiation-Protective Agents; D009556:Niobium; D000535:Aluminum