Laboratório de Ciências Radiológicas, Universidade do Estado do Rio de Janeiro, Brazil.
Br J Radiol. 2012 May;85(1013):629-35. doi: 10.1259/bjr/73088072. Epub 2011 Oct 18.
A spectrometric study of standard mammography-quality beams by using experimental and Monte Carlo simulation methods was carried out in this work. The qualities of these beams are described according to the International Electrotechical Commission 61267 standard and the Technical Report Series 457 International Atomic Energy Agency report. Specifically, the non-attenuated RQR-M beam series was studied.
A Si-PIN diode-based spectrometer and the PENELOPE Monte Carlo code (v. 2008F1) were used for experiments and simulations, respectively. In addition, an ionization chamber was used to determine the half-value layers (HVLs) of each beam quality. The measurements were done in the mammography dosimeter calibration setup of our laboratory, and the Monte Carlo simulations reproduced such conditions.
The relative differences between the HVLs calculated from experimental and simulated spectra were lower than 2.4% for all the beam qualities studied. These differences are 1.2% and 3.1% when comparing the HVLs calculated from the experimental and simulated spectra to those determined by using the ionization chamber, respectively. A semi-empirical relation was found to obtain the nominal tube potential from the effective tube potential.
According to our results, the mammography beams used in this work have energy spectra similar to clinical beams.
本研究采用实验和蒙特卡罗模拟方法对标准乳腺摄影质量束进行了光谱学研究。根据国际电工委员会 61267 标准和国际原子能机构技术报告系列 457 报告，对这些光束的质量进行了描述。具体来说，研究了非衰减的 RQR-M 光束系列。
使用基于 Si-PIN 二极管的光谱仪和 PENELPE 蒙特卡罗代码（v.2008F1）分别进行实验和模拟。此外，还使用电离室来确定每个光束质量的半值层（HVL）。测量是在我们实验室的乳腺摄影剂量计校准设置中进行的，蒙特卡罗模拟再现了这些条件。
对于所有研究的光束质量，从实验和模拟光谱计算得出的 HVL 的相对差异均低于 2.4%。当将从实验和模拟光谱计算得出的 HVL 与使用电离室确定的 HVL 进行比较时，这些差异分别为 1.2%和 3.1%。发现了一种半经验关系，可以从有效管电压获得标称管电压。
根据我们的结果，本工作中使用的乳腺摄影束具有与临床束相似的能谱。
