胸部X光前後位攝影管球投射角度最佳化之探討

Discussion of the Optimized X-ray Tube Projection Angle of the Chest AP Radiography

曾世瑋(Shih-Wei Tseng) ； 林義嵐(Yi-Lan Lin) ； 魏瑞慶(Raei-Ching Wei) ； 張凱程(Kai-Cheng Chang) ； 趙慶勇(Ching-Yung Chao) ； 劉盛璟(Sheng-Ching Liu) ； 徐世美(Shih-Mei Hsu)

《臺灣醫事放射期刊》 3卷1期 (2015/03) Pp. 9-14

https://doi.org/10.6717/JTMRT.201503_3(1).0002

摘要

放射醫學影像品質影響臨床醫師的診斷，因此在任何攸關影響影像品質之問題都應盡可能的去改善。同時在臨床操作上也因受檢者變動因素太多，放射師在操作儀器時需視臨床狀況而應變，例如當受檢者需進行胸部X 光前後位攝影 (chest AP，chest anterior toposterior) 時，床的角度、攝影片匣及管球角度均會影響影像品質。chest AP 常規攝影方式是管球與片匣的角度採平行之方式進行攝影時，當管球投射角度過大或太小均會影響影像品質。因此本研究是為探討chest AP 攝影管球投射角度與床的角度之關係，以達影像品質最佳化。其材料與方法是以人體骨模型進行檢查床及管球之各種角度之chest AP 攝影，評估適當的管球投射角度以達影像品質最佳化。另也驗證放射師於臨床操作時以目測方式調控管球角度的正確性，故應用傾角器測量床的傾斜角度後，進行三種床的角度，請18位放射師以目測方式依床的各種角度調整管球攝影角度，依其誤差值來評估人員目測方式之可靠性。期望藉由此研究可找出chest AP 攝影時管球最佳角度，同時使用便利精確的儀器及改變人員操作習慣，以科學方式取代舊有目視方式提升影像品質，另也可避免因管球角度不佳及影像品質差使醫師判讀困擾而需重照，故期望此研究結果能提供放射師在臨床執行chest AP 攝影的參考。

關鍵字

胸部X 光前後位攝影 ； 管球投射角度 ； 影像品質

並列摘要

In radiology, image quality can affect the diagnosis of clinicians. Therefore, it is necessary to improve image quality in every aspect. At the same time, because a considerable amount of varying factors exist as a result of the individual characteristics of examinees during a clinical operation, radiologic technologist must adapt to different actual clinical situations when operating the equipment. For example, when the examinee requires a chest anterior to posterior (chest AP) X-ray, the angle of the bed, IP Cassette, and the X-ray tube projection angle can all affect the image quality. The routine clinical photography mode for a chest AP is to have approximately parallel angles for both the tube and the cassette. A larger or smaller projection angle of the source can affect the image quality. Therefore, this study explores the relationship between the X-ray tube projection angle and the angle of the bed for chest AP, in order to achieve the best setup for optimal image quality. The material and methodology are as follows: In order to determine the best tube projection angle for the optimum quality chest AP image, Human Skeleton Model is used and chest AP images are taken for different angles of the examining table and tube. Also, in order to verify the correctness of the visual cassette angle of the radiologic technologist during clinical operation, an inclinometer is used to measure the angle of the bed. Three different angles of the bed are tested. A total of 18 radiologic technologist are invited to adjust the source projection angle based on their visual judgment of the various bed angles, in order to compare the differences between the angles and to verify the reliability of the visual judgment. The objective of the study is to find the optimal tube projection angle for a chest AP, and to alter the current operating practices by substituting the conventional visual judgment approach with more convenient, scientific, and precise instruments, to in turn increase the resultant image quality. This can also prevent difficulties for physicians as regards the interpretation of low quality images, and the necessity to retake images because of angle errors. The aim of this study is, therefore, for the results to serve as a useful reference for radiologic technologist during clinical chest AP imaging.

並列關鍵字

chest AP ； X-ray tube projection angle ； image quality