Martinsen Anne Catrine Traegde, Risdal Mona, Bay Tonje, Drolsum Anders
Avdeling for diagnostisk fysikk og teknikk, Radiologisk divisjon, Ullevål universitetssykehus, 0407 Oslo.
Tidsskr Nor Laegeforen. 2005 Aug 11;125(15):2023-5.
In 1993, Ullevaal University Hospital started CT pelvimetry. The accuracy of CT pelvimetric measurements and a low fetal dose are very important. In our study we tested the accuracy of CT pelvimetry and measured the fetal dose and the effective dose to the mother.
A lead scalar was exposed in different heights compared to the isocentre. Measurements were done at front and side scout views and compared to the real scale. Dose estimates were done in CT dosimetry (NRPB). Effective doses to patient as well as fetal doses were measured in this study. Fetal dose was estimated as uterus dose.
Our results show that the measurements are overestimates when the table is moved away from the isocentre against the tube. If the table is moved away from the tube and against the detector, the measurements are underestimates. The measurements in the isocentre are accurate. This means that CT pelvimetric measurements are accurate if the patient is placed in the isocentre. In our study the estimated fetal dose was 0.74 mGy and mother's effective dose was 0.3 mSv.
Our results show that the fetal dose is as low or lower than with conventional pelvimetry. The CT pelvimetric measurements are accurate if they are performed on patients in the isocentre. We recommend that CT pelvimetry replace conventional pelvimetry.
1993年，于勒凡厄尔大学医院开始采用CT骨盆测量法。CT骨盆测量的准确性以及低胎儿辐射剂量非常重要。在我们的研究中，我们测试了CT骨盆测量的准确性，并测量了胎儿辐射剂量和母亲所接受的有效剂量。
将一个铅质标尺放置在与等中心不同高度处。在前后位和侧位定位像上进行测量，并与实际标尺进行比较。采用CT剂量测定法（英国国家辐射防护委员会）进行剂量估算。本研究测量了患者的有效剂量以及胎儿剂量。胎儿剂量按子宫剂量估算。
我们的结果显示，当检查床背离球管远离等中心移动时，测量值会高估。如果检查床背离球管并朝着探测器移动，测量值会低估。在等中心进行的测量是准确的。这意味着如果患者位于等中心，CT骨盆测量是准确的。在我们的研究中，估算的胎儿剂量为0.74毫戈瑞，母亲的有效剂量为0.3毫希沃特。
我们的结果表明，胎儿剂量与传统骨盆测量法相当或更低。如果在位于等中心的患者身上进行CT骨盆测量，测量结果是准确的。我们建议CT骨盆测量法取代传统骨盆测量法。
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