Two thermal methods to measure the energy fluence of a brief exposure of diagnostic x rays.
This paper describes two simple thermal methods for measuring the energy fluence in J/cm2 from a diagnostic x-ray exposure. Both detectors absorb essentially 100% of the radiation and give a signal that is directly proportional to the energy fluence of the x-ray beam. One detector measures the thermal effect when a pulse of x rays is totally absorbed in the pyroelectric detector of lead-zirconium-titanate (PZT). The other detector measures the expansion of a gas surrounding a lead disk detector in a photoacoustic chamber. The increased pressure of the gas is transmitted through a 1-mm duct to a sensitive microphone. Both detectors have previously been used to measure the energy fluence rate of continuous x-ray beams in the same energy region using a chopped beam and a lock-in amplifier. Measurement of the energy fluence of a pulse of radiation eliminates the need for the beam chopper and lock-in amplifier and results in a simple, rugged, and inexpensive dosimeter. Either method can be combined with the area of the beam to give an estimate of the imparted energy to the patient from a diagnostic x-ray exposure.
Carvalho
A A
AA
Departamento de Engenharia Electrica, Univ. Est. Paulista, Ilha Solteira, S.P., Brazil.
Mascarenhas
S
S
dePaula
M H
MH
Cameron
J R
JR
D004735:Energy Transfer; D006801:Humans; D011829:Radiation Dosage; D011859:Radiography; D014965:X-Rays