直至目前磁振造影(magnetic resonance imaging MRI)已經在整體上對長時間的掃描結果，實際上並沒有長時問的產生生物效應，無論如何，如果從磁振造影系統的組成分開來檢查，應該要注意到一些效應，如磁體、梯度和射頻的範圍，大部分是不重要的效應而且是立刻可以恢復的，無論如何病人和工作人員的危險性是確信存在的，本文在討論而且清楚的評估磁振造影風險及危險顯然是相當重要，用長時間來討論磁振造影生物效應是非常有意義及有它的正確性，另一方面也應該注意考量影像組合的過程，那些元件沒有包含在主磁場範圍，同樣地如靜態磁場，但不同的梯度磁場和射頻所產生的轉收和接收線圈的反應，本文都會加以探討。

To date we have seen virtually no long-term adverse biological effects of extended exposure to MRI as a whole. However, if we examine separate components of the magnetic resonance imaging process we observe several effects of magnetic, gradient and radio frequency fields. Most are inconsequential and reversible, however, there are certain patient and operator risks, which should be discussed. The need to evaluate MR for potential risks and hazards is clear and, in order to validly discuss long-term biological effects of MRI, we should consider all of the components of the imaging process. Those elements include not only the main magnetic field also known as the static magnetic field, but also time varying magnetic fields caused by magnetic field gradients, and radiofrequency fields created by RF transmitter and receiver coils.