A method for detecting a liver health parameter of a patient, the method comprising: under control of processing electronics, receiving image data comprising a representation of detected radiation counts corresponding to one or more organs of a patient; determining a plurality of first boundary points of a liver of the patient in the image data, said determining comprising: identifying a body contour in the image data based on radiation count intensity comparisons, determining a liver boundary threshold from radiation count intensities in a border region around the body contour, and directionally searching the image data to compare intensities of radiation counts with the liver boundary threshold to identify the plurality of first boundary points; calculating a centroid of the liver from the first boundary points; determining a plurality of second boundary points of a spleen of the patient in the image data and calculating a centroid of the spleen from the second boundary points in a similar manner as defined above for the liver; identifying a first region of interest corresponding to the liver of the patient from the determined plurality of first boundary points and the centroid of the liver; identifying a second region of interest corresponding to the spleen of the patient from the determined plurality of second boundary points and the centroid of the spleen; determining a first parameter indicative of health of a patient based at least in part on a first attribute associated with the first region of interest and optionally also based on a second attribute associated with the second region of interest; and generating an output responsive to the first parameter for presentation to a clinician, wherein the output comprises one or more of a value of the first parameter and a health report associated with the first parameter. receiving image data comprising a representation of detected radiation counts corresponding to one or more organs of a patient; determining a plurality of first boundary points of a liver of the patient in the image data, said determining comprising: identifying a body contour in the image data based on radiation count intensity comparisons, determining a liver boundary threshold from radiation count intensities in a border region around the body contour, and directionally searching the image data to compare intensities of radiation counts with the liver boundary threshold to identify the plurality of first boundary points; identifying a body contour in the image data based on radiation count intensity comparisons, determining a liver boundary threshold from radiation count intensities in a border region around the body contour, and directionally searching the image data to compare intensities of radiation counts with the liver boundary threshold to identify the plurality of first boundary points; calculating a centroid of the liver from the first boundary points; determining a plurality of second boundary points of a spleen of the patient in the image data and calculating a centroid of the spleen from the second boundary points in a similar manner as defined above for the liver; identifying a first region of interest corresponding to the liver of the patient from the determined plurality of first boundary points and the centroid of the liver; identifying a second region of interest corresponding to the spleen of the patient from the determined plurality of second boundary points and the centroid of the spleen; determining a first parameter indicative of health of a patient based at least in part on a first attribute associated with the first region of interest and optionally also based on a second attribute associated with the second region of interest; and generating an output responsive to the first parameter for presentation to a clinician, wherein the output comprises one or more of a value of the first parameter and a health report associated with the first parameter.