Purpose

Diagnostic reference levels (DRL) and achievable doses (AD) are important tools for radiation dose optimization. Therefore, a prospective study was performed which aimed to establish a multi-parametric, clinical indication based – DRL(DRL_CI) and clinical indication – AD (AD_CI) for adult CT in Brazil.

Methods

The prospective study included 4787 patients (50 ± 18 years old; male:female 2041:2746) at 13 Brazilian sites that have been submitted to head, paranasal sinus, cervical spine, chest, or abdomen-pelvis CT between January and October 2021 for 13 clinical indications. The sites provided the following information: patient age, gender, weight, height, body mass index[BMI], clinical indications, scanner information(vendor, model, detector configuration), scan parameters (number of scan phases, kV, mA, pitch) and dose-related quantities (CT dose index volume- CTDI_vol, dose length product- DLP). Median(AD) and 75th(DRL) percentile CTDI_vol and DLP values were estimated for each body region and clinical indications. Non-normal data were analyzed with the Kruskal-Wallis test.

Results

In majority of Brazilian sites, body region and clinical indications based DRLs were at or lower than the corresponding DRLs in the US and higher than Europe. Although radiation doses varied significantly for patients in different body mass index groups (p < 0.001), within each body region, there were no differences in radiation doses for different clinical indications (p > 0.1). Radiation doses for 7/13 clinical indications were higher using iterative reconstruction technique than for the filtered back projection.

Conclusions

There was substantial variation in Brazil DRL_CI across different institutions with higher doses compared to the European standards. There was also a lack of clinical indication-based protocol and dose optimization based on different clinical indications for the same body region.

中文翻译：

---

巴西建立国家临床诊断参考水平和 CT 检查可达到的剂量：一项前瞻性研究

 目的

诊断参考水平 (DRL) 和可达到剂量 (AD) 是辐射剂量优化的重要工具。因此，进行了一项前瞻性研究，旨在为巴西成人 CT 建立基于多参数、临床适应症的 DRL (DRL _CI ) 和临床适应症 AD (AD _CI )。

 方法

这项前瞻性研究纳入了巴西 13 个地点的 4787 名患者（50 ± 18 岁；男性：女性 2041：2746），这些患者在 2021 年 1 月至 10 月期间接受了头部、鼻旁窦、颈椎、胸部或腹盆腔 CT 检查13个临床适应症。这些网站提供了以下信息：患者年龄、性别、体重、身高、体重指数 [BMI]、临床适应症、扫描仪信息（供应商、型号、探测器配置）、扫描参数（扫描阶段数、kV、mA、间距）和剂量相关量（CT 剂量指数体积 - CTDI _vol 、剂量长度乘积 - DLP）。估计每个身体区域和临床适应症的中位 (AD) 和第 75 个百分位数 (DRL) CTDI _vol和 DLP 值。非正态数据采用 Kruskal-Wallis 检验进行分析。

 结果

在巴西的大多数地点，基于身体区域和临床适应症的 DRL 等于或低于美国相应的 DRL，但高于欧洲。尽管不同体重指数组患者的辐射剂量存在显着差异（p < 0.001），但在每个身体区域内，不同临床适应症的辐射剂量没有差异（p > 0.1）。使用迭代重建技术的 7/13 临床适应症的辐射剂量高于滤波反投影的辐射剂量。

 结论

与欧洲标准相比，不同机构的巴西 DRL _CI剂量较高，差异很大。还缺乏基于临床适应症的方案以及针对同一身体区域的不同临床适应症的剂量优化。