Abstract: A method for detecting a radionuclide using energy spectrum data represented by a count depending on energy obtained from a radiation detector, including: calculating a count ratio for a particular energy value using a background energy spectrum data measured without a target object to detect the radionuclide and a target energy spectrum measured in the presence of the target object; and comparing a background count ratio and a target object count ratio, where the count ratio is a ratio of a low count sum of count values which is an energy value or less divided by a high count sum of the count values which is greater than the particular energy value, or a ratio of the low count sum of the count values which is smaller than the particular energy value divided by the high count sum of the count values which is the particular energy value or greater.

Abstract: A method for detecting a radionuclide using energy spectrum data represented by a count depending on energy obtained from a radiation detector, including: calculating a count ratio for a particular energy value using a background energy spectrum data measured without a target object to detect the radionuclide and a target energy spectrum measured in the presence of the target object; and comparing a background count ratio and a target object count ratio, where the count ratio is a ratio of a low count sum of count values which is an energy value or less divided by a high count sum of the count values which is greater than the particular energy value, or a ratio of the low count sum of the count values which is smaller than the particular energy value divided by the high count sum of the count values which is the particular energy value or greater.