Abstract: Disclosed is a process for preparing a radiation image storage panel having a phosphor layer containing an activated stimulable phosphor, characterized in that applying a heat treatment that can secure the content of an activator in the activated stimulable phosphor.Disclosed is also a process for preparing a radiation image storage panel having a layer of a stimulable phosphor layer activated with an activator, wherein a stimulable phosphor matrix layer is formed, and thereafter the activator is diffusion added to the layer to form a stimulable phosphor layer.

Abstract: Disclosed are a method for converting radiographic image which comprises the steps of:(a) storing radiation energy-corresponding to a radiographic image in a stimulable phosphor of a panel comprising a stimulable phosphor-containing layer,(b) scanning the layer with a stimulating ray to release the stored energy as a fluorescence, and(c) detecting the fluorescence to form an image, wherein the stimulable phosphor is represented by the following formula:(M.sub.1-x.M.sup.I.sub.x)X.aM.sup.II X'.sub.2.bM.sup.III X".sub.3 :dBwherein M represents either Cs or Rb; M.sup.I represents at least one of alkaline metals selected from the group consisting of Li, Na, K, Rb and Cs; M.sup.II represents at least one divalent meal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu and Ni; M.sup.