Disclosed herein is a system comprising: a plurality of X-ray detectors； wherein the X-ray detectors are configured to be positioned at different locations relative to the thyroid of a person, and to capture images of the thyroid with characteristic X-rays of iodine. Each of the X-ray detectors may comprise an array of pixels. The system may further comprise a collimator configured to limit fields of view of the pixels. Disclosed herein is a method comprising: causing emission of characteristic X-rays of iodine inside the thyroid of a person； capturing images of the thyroid with the characteristic X-rays, using a plurality of X-ray detectors positioned at different locations relative to the thyroid； determining a three-dimensional distribution of the iodine in the thyroid based on the images.本文公開一種系統，其包括：多個X射線檢測器；其中所述X射線檢測器配置成相對於人的甲狀腺被定位在不同位置，並用碘的特徵X射線來捕獲所述甲狀腺的圖像。每個所述X射線檢測器可包括一個圖元陣列。所述系統還可進一步包括準直器，所述準直器配置成限制所述圖元的視場。本文公開一種方法，其包括：引起人的甲狀腺內碘的特徵X射線的發射；用位於相對於所述甲狀腺的不同位置的多個X射線檢測器捕獲具有所述特徵X射線的所述甲狀腺圖像；基於所述圖像確定所述甲狀腺中所述碘的三維分佈。
