Low-energy X-ray imaging of prompt secondary electron bremsstrahlung X-rays (prompt X-rays) emitted during particle-ion irradiation is a promising method for range estimation. However, measurements have so far been conducted mainly for uniform phantoms of water or an acrylic block. Prompt X-ray imaging for phantoms with air cavities has not yet been extensively measured or evaluated with realistic conditions. Consequently, we conducted imaging of prompt X-rays using a pinhole YAP(Ce) camera during irradiation by protons as well as carbon ions to non-uniform acrylic phantoms with small cavities and then evaluated the images and estimated the ranges from the measured prompt X-ray images. The non-uniform acrylic phantom used for imaging had a cylindrical cavity with a 20-mm or 10-mm diameter in the phantom. During irradiation by protons or carbon ions, imaging of one of the phantoms was conducted using the pinhole YAP(Ce) camera with an air cavity as well as filling the cavity with an acrylic rod. For the phantom with a 20-mm-diameter cavity, the prompt X-ray images measured for both protons and carbon ions showed the shape of the cavity in the images, and the ranges could be estimated from the images. For the phantom with a 10-mm-diameter hole, although the shape of the hole could not be clearly observed, the ranges could also be estimated from the images. Furthermore, Monte Carlo simulated prompt X-ray images with different spatial resolution of the X-ray camera showed similar images to the measured images. We confirmed that prompt X-ray imaging of phantoms with air cavities using the pinhole YAP(Ce) cameras was possible and that prompt X-ray imaging is a promising approach for estimating the ranges for both protons and carbon ions, even for phantoms with air cavities.

粒子离子辐照期间发射的瞬发二次电子轫致辐射 X 射线（瞬发 X 射线）的低能 X 射线成像是一种很有前途的距离估计方法。然而，迄今为止，测量主要是针对均匀的水幻影或丙烯酸块进行的。尚未在现实​​条件下广泛测量或评估具有空气腔的体模的快速 X 射线成像。因此，我们在质子和碳离子照射期间使用针孔 YAP(Ce) 相机对具有小腔的非均匀丙烯酸幻影进行了瞬发 X 射线成像，然后评估图像并估计测量的瞬发 X 的范围-射线图像。用于成像的非均匀亚克力体模在体模中有一个直径为 20 毫米或 10 毫米的圆柱形空腔。在质子或碳离子照射期间，使用带有空气腔的针孔 YAP(Ce) 相机以及用丙烯酸棒填充腔体对其中一个体模进行成像。对于具有 20 毫米直径腔的体模，对质子和碳离子测量的即时 X 射线图像显示图像中腔的形状，并且可以从图像估计范围。对于具有 10 毫米直径孔的体模，虽然无法清楚地观察到孔的形状，但也可以从图像中估计其范围。此外，蒙特卡罗模拟具有不同空间分辨率的 X 射线相机的即时 X 射线图像显示出与测量图像相似的图像。