Kanani Abolfazl, Fatemi-Ardakani Ali, Owrangi Amir M, Yazdi Mehran, Baghbani Hadi, Mosleh-Shirazi Mohammad Amin
Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
Department of Physics, Jackson State University (JSU), Jackson, Mississippi, USA.
J Biomed Phys Eng. 2023 Dec 1;13(6):523-534. doi: 10.31661/jbpe.v0i0.2309-1665. eCollection 2023 Dec.
The BEBIG Portio multi-channel applicator provides better target dose coverage and sparing organs-at-risk compared to a single-channel cylinder. However, artifacts and distortions of Portio in magnetic resonance images (MRI) have not yet been reported.
We aimed to quantify the artifacts and distortions in its 1.5-Tesla MR images before clinical use.
In this experimental study, we employed a gelatin-filled phantom to conduct our measurements. T2-weighted (T2W) images were examined for artifacts and distortions. Computed tomography (CT) images were used as a reference to assess image distortions. Artifact severity was measured by recording the full-width-at-half-maximum (FWHM) image pixel values at various positions along the length of the applicator/channels. CT and MRI-based applicator reconstruction accuracy were then compared, and signal-to-noise ratio (SNR) and contrast were also determined for the applicator images.
The applicator distortion level for the Portio applicator was less than the image spatial resolution (0.5±0.5 pixels). The average FWHM for the tandem applicator images was 5.23±0.39 mm, while it was 3.21±0.37 mm for all channels (compared to their actual diameters of 5.0 mm and 3.0 mm, respectively). The average applicator reconstruction difference between CT and MR images was 0.75±0.30 mm overall source dwell positions. The image SNR and contrast were both acceptable.
These findings indicate that the Portio applicator has a satisfactory low level of artifacts and image distortions in 1.5-Tesla, T2W images. It may, therefore, be a promising option for MRI-guided multi-channel vaginal brachytherapy.
与单通道圆柱体相比，BEBIG Portio多通道施源器能提供更好的靶区剂量覆盖并保护危及器官。然而，Portio在磁共振成像（MRI）中的伪影和畸变尚未见报道。
我们旨在量化其在临床使用前1.5特斯拉MR图像中的伪影和畸变。
在本实验研究中，我们使用填充明胶的体模进行测量。检查T2加权（T2W）图像中的伪影和畸变。使用计算机断层扫描（CT）图像作为参考来评估图像畸变。通过记录沿施源器/通道长度不同位置处的半高宽（FWHM）图像像素值来测量伪影严重程度。然后比较基于CT和MRI的施源器重建精度，并确定施源器图像的信噪比（SNR）和对比度。
Portio施源器的施源器畸变水平小于图像空间分辨率（0.5±0.5像素）。串联施源器图像的平均FWHM为5.23±0.39毫米，而所有通道的平均FWHM为3.21±0.37毫米（分别与其实际直径5.0毫米和3.0毫米相比）。CT和MR图像之间施源器重建的平均差异在整个源驻留位置为0.75±0.30毫米。图像SNR和对比度均可接受。
这些发现表明，Portio施源器在1.5特斯拉T2W图像中具有令人满意的低水平伪影和图像畸变。因此，它可能是MRI引导下多通道阴道近距离放射治疗的一个有前景的选择。
