The purpose of the present development is to employ 3D printing to prototype an ion chamber array with a scalable design potentially allowing increased spatial resolution and a larger active area. An additional goal is to design and fabricate a custom size thin-panel detector array with low-Z components. As a proof of principle demonstration, a medium size detector array with 30 × 30 air-vented ion chambers was 3D-printed using PLA as frame for the electrodes. The active-area is 122 mm × 120 mm with 4 × 4 mm2 spatial resolution. External electrodes are cylindrical and made from conductive PLA. Internal electrodes are made from microwire. The array is symmetric with respect to the central plane and its thickness is 10 mm including build-up/-down plates of 2.5 mm thickness. Data acquisition is realized by biasing only selected chamber rows and reading only 30 chambers at a time. To test the device for potential clinical applications, 1D dose profiles and 2D dose maps with various square and irregular fields were measured. The overall agreement with the reference doses (film and treatment planning system) was satisfactory, but the measured dose differs in the penumbra region and in the field size dependence. Both of these features are related to the thin walls between neighboring ion chambers and different lateral phantom scatter in the detector panel vs homogeneous material. We demonstrated feasibility of radiation detector arrays with minimal number of readout channels and low-cost electronics. The acquisition scheme based on selected row or column 'activation' by bias voltage is not practical for 2D dosimetry but it allows for rapid turn-around when testing of custom arrays with the aid of multiple 1D dose profiles. Future progress in this area includes overcoming the limitations due high chamber packing ratio, which leads to the lateral scattering effects.

中文翻译：

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迈向可定制的薄板低Z检测器阵列：电极设计可提高空间分辨率的离子室阵列。

本开发的目的是采用3D打印来设计具有可扩展设计的离子室阵列的原型，从而潜在地增加空间分辨率并增加有效面积。另一个目标是设计和制造具有低Z分量的定制尺寸的薄型探测器阵列。作为原理验证的证明，使用PLA作为电极框架，对具有30×30通风离子室的中等尺寸检测器阵列进行了3D打印。活动区域为122 mm×120 mm，空间分辨率为4×4 mm2。外部电极为圆柱形，由导电PLA制成。内部电极由微丝制成。该阵列相对于中心平面对称，其厚度为10毫米，包括厚度为2.5毫米的增/减板。通过仅偏置选定的腔室行并一次仅读取30个腔室来实现数据采集。为了测试该设备的潜在临床应用，测量了具有各种正方形和不规则区域的一维剂量分布图和二维剂量图。与参考剂量（胶片和治疗计划系统）的总体协议令人满意，但是在半影区和视场大小依赖性方面，所测得的剂量有所不同。这两个特征都与相邻离子室之间的薄壁以及检测器面板与均质材料中不同的横向幻像散射有关。我们展示了具有最少数量的读出通道和低成本电子设备的辐射探测器阵列的可行性。基于选定的行或列“激活”的采集方案 对于2D剂量测定来说，通过偏置电压来测量电压是不切实际的，但是在借助多个1D剂量分布图测试定制阵列时，它可以实现快速周转。该领域的未来进展包括克服由于高室填充率而导致的局限性，从而导致横向散射效应。