Effects of image enhancer on the dose to marginal target areas of esophageal cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第11期
- Page:
- 1267-1271
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Effects of image enhancer on the dose to marginal target areas of esophageal cancer
- Author(s):
- WANG Yong; CAI Yuxin; ZHANG Lingling; LI Junping; HUANG Lumao
- Department of Radiotherapy, Quanzhou First Hospital of Fujian Medical University, Quanzhou 362000, China
- Keywords:
- esophageal cancer; marginal target area; dose; image enhancer
- PACS:
- R811
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.11.005
- Abstract:
- Objective To study whether the dose to marginal target areas of esophageal cancer near the heart, thoracic aorta and other tissues with abundant blood flow will be decreased after the use of image enhancer in intensity-modulated radiotherapy, and whether there will be insufficient exposure. Methods Twenty cases of esophageal cancer were selected. After plain scan and enhanced CT scan were performed in the same position, target areas were delineated in enhanced CT image and intensity-modulated radiotherapy plan was designed. Two methods were used for comparison. In method (1), two marginal target areas of PTV & 5 mm Aorta and PTV & 5 mm Heart were delineated in enhanced and plain CT, and then image registration was performed and the treatment plan was transplanted to plain CT for dose calculation. The dose changes of two marginal target areas in enhanced and plain CT were compared. In method (2), since enhanced and plain CT scans were carried out at different time points, there were certain differences between the two images during registration. In order to avoid the effects caused by body position deviation, synthetic CT was compared with enhanced CT. The synthetic CT means that in the replicated enhanced CT, the CT values of the heart, thoracic aorta and other tissues with abundant blood flow were artificially modified to the average CT value of plain CT. The operation process was the same as method (1), and the dose changes of two marginal target areas were observed. The dose changes of other tissues and organs in plain and enhanced CT were also compared. Results Both methods (1) and (2) showed an increase in the dose to two marginal target areas, PTV & 5 mm Aorta and PTV & 5 mm Heart. In method (1), the doses to the two marginal target areas were increased by 1.28% (P<0.01) and 1.64% (P<0.01), respectively, while in method (2), the dose were increased by 0.41% (P<0.01) and 0.83% (P<0.01), respectively. The doses to normal tissues (heart, lungs, spinal cord, etc.) which were also increased were still within the clinically acceptable range. Conclusion After the use of image enhancer, the doses to marginal target areas of esophageal cancer near the heart, thoracic aorta and other tissues with abundant blood flow, are increased, and there is no insufficient exposure.
Last Update: 2019-11-28