摘要
This study presents the results of the preliminary tests performed using a kerma-area product (KAP) meter in order to verify its usefulness as a monitor chamber in a clinical X ray system, which will be used in ionization chambers’ quality control program. The tests performed were repeatability, surface measurement uniformity, linearity with tube current, measurement variation changing the distance and field size, KAP chamber radiation attenuation, and energy dependence. The KAP meter has presented a good repeatability (a maximum variation of 0.4%);its surface has a homogeneous response (a maximum variation of 1.0% among the different irradiated regions);the response is linear with the tube current and the variation of the PKA along the distance is less than 3.43%. On the other hand, the results obtained for chamber attenuation and energy dependence show that some corrections must be applied when the measurements are made. The results have shown a good performance of the KAP meter, confirming that it is possible to use this instrument as a monitor chamber. However, it is important to highlight that some correction factors for energy dependence and chamber radiation attenuation must be considered.
This study presents the results of the preliminary tests performed using a kerma-area product (KAP) meter in order to verify its usefulness as a monitor chamber in a clinical X ray system, which will be used in ionization chambers’ quality control program. The tests performed were repeatability, surface measurement uniformity, linearity with tube current, measurement variation changing the distance and field size, KAP chamber radiation attenuation, and energy dependence. The KAP meter has presented a good repeatability (a maximum variation of 0.4%);its surface has a homogeneous response (a maximum variation of 1.0% among the different irradiated regions);the response is linear with the tube current and the variation of the PKA along the distance is less than 3.43%. On the other hand, the results obtained for chamber attenuation and energy dependence show that some corrections must be applied when the measurements are made. The results have shown a good performance of the KAP meter, confirming that it is possible to use this instrument as a monitor chamber. However, it is important to highlight that some correction factors for energy dependence and chamber radiation attenuation must be considered.
