Gafchromic EBT2 Film Response at X-Ray Energies From 4.5 KeV to 50 KVp
M Tucker, J Rakowski*, Wayne State University School of Medicine Dept. of Radiation Oncology, Detroit, MISU-E-T-96 Sunday 3:00PM - 6:00PM Room: Exhibit Hall
Purpose:Our intent is to measure the energy dependent response of Gafchromic EBT2 film to fluorescent Kα/Kβ x-ray energies from 4.51 to 19.61 keV, and tungsten bremsstrahlung spectrum at 50 kVp of mean energy 23.3 keV.
Methods:Fluorescent x-rays were generated using a silver anode x-ray spectrum upon high purity metals Ti, Fe, Cr, Co, Zn, and Mo. Fluorescent x-ray dose rates were measured with an extrapolation ion chamber model EIC-1 manufactured by Far West Technology, Inc., (Goleta, CA). Tungsten Bremsstrahlung x-ray dose rate was measured with an NIST-traceable Radcal 10X5-6 ion chamber. Film was exposed to doses ranging up to 800 cGy and scanned in TIFF format at 72 ppi and 48 bits RGB using a Microtek Scanmaker i800 transmission scanner, according to the film manufacturer recommendations. Net optical density is plotted versus dose (cGy).
Results:Net optical density increased with photon energy, varying by a factor of 1.5 between lowest and highest energies at all doses.
Conclusion:Gafchromic EBT2 displays definite energy dependence at low x-ray energies ranging from the fluorescent 4.5 keV to 50 kVp spectrum of mean energy 23.3 keV. The general trend with energy agrees with other studies performed at higher energies.
Funding Support, Disclosures, and Conflict of Interest: Wayne State University School of Medicine Fund for Medical Research and Education