Efficiency calibration of 3″ × 3″ NaI(Tl) crystals

Chinaglia, B.; Malvano, R.

doi:10.1016/0029-554x(66)90416-2

Cited by 19 publications

(2 citation statements)

References 10 publications

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“…In the measurement, the source to detector distance was 100 cm, and the detector was shielded by lead blocks with a 0.5 cmϕ hole as in the measurement of the response function. Since the photopeak distribution forms a Gaussian curve, calculated FWHM was used to predict the spread of the photopeak by fitting it to a Gaussian distribution 28 …”

Section: Methodsmentioning

confidence: 99%

“…Code, version EGSnrc, 22 2018 BEAMnrc, 24 2013 DOSXYZnrc, 25 calculated FWHM was used to predict the spread of the photopeak by fitting it to a Gaussian distribution. 28 The calculated spread of the photopeak distribution was compared with the measured value and incorporated into the calculated response function. Also, calculated photopeak efficiency ε p was compared with measured one to verify the validity of the calculation.…”

Section: Response Function Energy Spectrum Pddmentioning

confidence: 99%

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Direct energy spectrum measurement of X‐ray from a clinical linac

Suda

Hariu

Yamauchi

et al. 2021

J Applied Clin Med Phys

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A realistic X‐ray energy spectrum is essential for accurate dose calculation using the Monte Carlo (MC) algorithm. An energy spectrum for dose calculation in the radiation treatment planning system is modeled using the MC algorithm and adjusted to obtain acceptable agreement with the measured percent depth dose (PDD) and off‐axis ratio. The simulated energy spectrum may not consistently reproduce a realistic energy spectrum. Therefore, direct measurement of the X‐ray energy spectrum from a linac is necessary to obtain a realistic spectrum. Previous studies have measured low photon fluence directly, but the measurement was performed with a nonclinical linac with a thick target and a long target‐to‐detector distance. In this study, an X‐ray energy spectrum from a clinical linac was directly measured using a NaI(Tl) scintillator at an ultralow dose rate achieved by adjusting the gun grid voltage. The measured energy spectrum was unfolded by the Gold algorithm and compared with a simulated spectrum using statistical tests. Furthermore, the PDD was calculated using an unfolded energy spectrum and a simulated energy spectrum was compared with the measured PDD to evaluate the validity of the unfolded energy spectrum. Consequently, there was no significant difference between the unfolded and simulated energy spectra by nonparametric, Wilcoxon's rank‐sum, chi‐square, and two‐sample Kolmogorov–Smirnov tests with a significance level of 0.05. However, the PDD calculated from the unfolded energy spectrum better agreed with the measured compared to the calculated PDD results from the simulated energy spectrum. The adjustment of the incident electron parameters using MC simulation is sensitive and takes time. Therefore, it is desirable to obtain the energy spectrum by direct measurement. Thus, a method to obtain the realistic energy spectrum by direct measurement was proposed in this study.

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Section: Methodsmentioning

confidence: 99%