Majurin M L, Valavaara R, Varpula M, Kurki T, Kulmala J
Department of Diagnostic Radiology, Turku University Central Hospital, Finland.
Eur J Radiol. 1995 Jul;20(2):114-9. doi: 10.1016/0720-048x(95)00639-8.
Twenty-seven consecutive breast cancer patients receiving tangential field radiation therapy were followed by high resolution CT (HRCT) in order to compare the accuracy of reduced-dose HRCT and conventional-dose HRCT in the evaluation of subtle pulmonary changes. Thin section 1-mm HRCT images were obtained at identical levels at 120 kVp, with 320 mAs, 200 mAs, 160 mAs, 120 mAs and 60 mAs settings. HRCT was performed during the planning of radiotherapy and 4, 8 and 24 weeks after the completion of radiotherapy. Radiation was administered according to an individual CT-based plan by tangential fields with 4 or 6 MV photons to the whole breast given with 5 fractions of 1.9 Gy weekly to a total dose of 50 Gy. The tumor bed was boosted by electrons to 60 Gy. Pathological changes were detected in 21 examinations of 10 patients: 9 patients out of 27 (33%) showed radiation induced changes; 1 patient developed metastases within the irradiated volume. Septal thickening appeared in 5 patients at 4 weeks and in another 5 patients at 8 weeks. Parenchymal consolidation was detected in 1 patient at 4 weeks and in 5 patients at 8 weeks. HRCT using 160 mAs yield good quality images of subtle radiation induced injuries. The diagnostic validity of HRCT using lower than 160 mAs depends on the detail analyzed.
对27例接受切线野放射治疗的乳腺癌患者进行高分辨率CT（HRCT）随访，以比较低剂量HRCT和常规剂量HRCT在评估细微肺部变化方面的准确性。在120 kVp下，分别以320 mAs、200 mAs、160 mAs、120 mAs和60 mAs的设置，在相同层面获取1毫米薄层HRCT图像。HRCT在放射治疗计划期间以及放射治疗完成后的4周、8周和24周进行。放射治疗根据基于个体CT的计划，通过切线野给予整个乳房4或6 MV光子，每周5次，每次1.9 Gy，总剂量50 Gy。肿瘤床通过电子束追加剂量至60 Gy。在10例患者的21次检查中检测到病理变化：27例患者中有9例（33%）出现放射诱导的变化；1例患者在照射区域内发生转移。5例患者在4周时出现间隔增厚，另有5例患者在8周时出现。1例患者在4周时出现实质实变，5例患者在8周时出现。使用160 mAs的HRCT能产生细微放射诱导损伤的高质量图像。使用低于160 mAs的HRCT的诊断有效性取决于所分析的细节。
