Aims and objectives
Exposure to diagnostic X-rays provides certain benefits for patients.
At the same time,
it involves some risks such as the development of cancer [1].
To assess the level of risk of radiation exposure in X-ray diagnosis,
evaluation of the irradiated dose is essential.
One useful method to evaluate the dose precisely is to measure the irradiated dose directly by wearing a dosimeter during diagnosis.
Thus,
we have studied the applicability of the nanoDot,
a small type optically stimulated luminescence (OSL) dosimeter,
for dosimetry in the...
Methods and materials
The calibration factors were evaluated by the Monte Carlo simulation code,
EGS5 [12].
The nanoDot,
shown in Figure 2, was irradiated by 1.0×107 particles of parallel X-ray beam.
Regarding the information of the nanoDot dimensions,
we referred to the research of Lehmann et al.
[13].
The composition of Al2O3 was also determined by a previous study [9].Table1shows the irradiation condition used in this study.
The energy spectra of X-rays were calculated by the Birch-Marshall formula [14] with the information of tube voltage and filters.
The...
Results
The energy spectrum of diagnostic X-rays and monochromatic X-rays is shown in Figure 3.
The effective energy of each X-ray spectrum is shown in Table 1.
The energy spectra of diagnostic X-rays were broad.
The maximum energy of X-rays corresponds to the tube voltage,
but the minimum energy hardly changes.
Thus,
when the tube voltage changed from 40 to 140 kV,
the effective energy of the diagnostic X-ray varied between 25 and 44 keV.
On the other hand,
the energy spectra of monochromatic X-rays were...
Conclusion
We have studied the reliability of the dose evaluation when using nanoDot OSL dosimeters during X-ray diagnosis.
Since the response of the nanoDot has energy dependence in the energy range of diagnostic X-rays,
calibration of the reader with respect to the nanoDot response irradiated to a certain diagnostic X-ray energy range should be performed.
In this study,
we evaluated the nanoDot calibration factors due to different X-ray qualities,
i.e.,
we compared the nanoDot calibration factors for 40 – 140 kV X-rays for radiography,
20,
40,...
References
[1] A.
B.
Gonzalez and S.
Darby,
Risk of cancer from diagnostic X-rays: estimates for the UK and 14 other countries,
The Lancet,
363,
345-351 (2004)
[2] H.
Hayashi,
et al.,
Procedure to measure angular dependences of personal dosimeter by means of diagnostic X-ray equipment.
Medical Imaging and Information Sciences,
32(1),
8-14 (2015)
[3] K.
Takegami,
et al.,
Energy dependence measurement of small-type optically stimulated luminescence (OSL) dosimeter by means of characteristic X-rays induced with general diagnostic X-ray equipment.
Radiological Physics and Technology 9(1),
99-108...