| Gao Liugang,Sun Hongfei,Xie Kai,Lin Tao,Sui Jianfeng,Ni Xinye.Effects of metal artifact correction based on 12 and 16 bit CT images on dose distribution in radiotherapy[J].Chinese Journal of Radiological Medicine and Protection,2017,37(12):938-945 |
| Effects of metal artifact correction based on 12 and 16 bit CT images on dose distribution in radiotherapy |
| Received:July 18, 2017 |
| DOI：10.3760/cma.j.issn.0254-5098.2017.12.012 |
| KeyWords:Metallic implants Radiotherapy Dose Computed tomography Artifacts |
| FundProject:江苏省自然科学基金（BK20151181） |
| Author Name | Affiliation | E-mail | | Gao Liugang | Department of Radiation Oncology, Changzhou No.2 People's Hospital, Nanjing Medical University, Changzhou 213003, China | | | Sun Hongfei | Department of Radiation Oncology, Changzhou No.2 People's Hospital, Nanjing Medical University, Changzhou 213003, China | | | Xie Kai | Department of Radiation Oncology, Changzhou No.2 People's Hospital, Nanjing Medical University, Changzhou 213003, China | | | Lin Tao | Department of Radiation Oncology, Changzhou No.2 People's Hospital, Nanjing Medical University, Changzhou 213003, China | | | Sui Jianfeng | Department of Radiation Oncology, Changzhou No.2 People's Hospital, Nanjing Medical University, Changzhou 213003, China | | | Ni Xinye | Department of Radiation Oncology, Changzhou No.2 People's Hospital, Nanjing Medical University, Changzhou 213003, China | nxy2000@aliyun.com |
|
| Hits: 2828 |
| Download times: 1438 |
| Abstract:: |
| Objective To apply metal artifact reduction algorithm to reduce metal artifacts based on 12 bit and 16 bit CT images, and aimed to analyze the effects on CT value and dose distribution. Methods The metal implant was inserted into the phantom, and the original 12 bit CT image and original 16 bit CT image were derived from CT scanning. The images were processed using NMAR algorithm, so the corrected 12 bit image and corrected 16 bit image were obtained. A patient's CT was chosen with artificial femur, and used the NMAR algorithm to reduce metal artifacts. Furthermore, the CT values of original images and corrected images were compared and analyzed. In the planning system, dose distribution was calculated based on each image by same radiation treatment plan. The dose distribution difference of each image was compared and analyzed. Results For the 12 bit image, the CT value of metal was 3 071 HU, which was much smaller than the metal's actual CT value 11 080 HU. The metal's CT value for the 16bit image was 11 098 HU, which was very close to the actual value. The original CT images contained a lot of artifacts around the metal, resulting in a large deviation of CT values from the reference image. After NMAR correction, metal artifacts were reduced significantly, and the CT values were close to the reference images. The dose distribution of the corrected 16 bit image was closest to that of the reference image. The maximum dose deviation on the central axis was 1.8%. The difference between the 12 bit image and the reference image downstream the metal was notable, and the maximum dose deviation on the central axis was 81.6%. The X-rays passed through the artifact region in original image, the dose distribution was obviously different from the reference image, and the maximum dose deviation was 21.6%. Conclusions For the patient with metal implant, using the NAMR algorithm on the 16 bit image result in accurate CT value of CT image, so that the accurate dose distribution will be obtained. |
| HTML View Full Text View/Add Comment Download reader |
| Close |
|
|
|
