The U.K. Royal College of Radiologists (RCR) has issued guidelines on incidental radiation of the spleen. The 10-page document is free to download from the RCR website.
The guidance applies to all patients who may receive radiotherapy to the spleen. It is a defined organ at risk as a result of being referred for radiotherapy to the upper abdomen or an adjacent anatomical site where the upper abdomen might also be irradiated.
Read more about the guidelines: https://www.auntminnieeurope.com/index.aspx?sec=sup&sub=cto&pag=dis&ItemID=620971