You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["AnatomicalEntity"].

Please return the output as a JSON object of the format: {"AnatomicalEntity": ["tumor cells", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Imaging techniques for the assessment of body composition.
Three imaging methods, ultrasound imaging (UI), computer-assisted axial tomography (CAT) and magnetic resonance imaging (MRI), are widely used in medicine. Their application to the assessment of body composition in nutrition research is still being explored and developed. Ultrasound imaging yields poor image quality but, because it is cheap and safe, deserves further exploration. Both CAT and MRI can produce images with good discrimination among bone, muscle and adipose tissue. Movement artifacts tend to be more serious in MRI than in CAT due to the longer imaging time. On the other hand, the X-ray exposure in CAT is likely to limit its use in human nutrition research. Repeated measurements of tissue volumes by CAT and MRI give similar CV. In both CAT and MRI, intra-abdominal adipose tissue presents greater problems of measurement than subcutaneous adipose tissue. Validation studies with 77-kg pigs of MRI, using 13 slices, predicted total body lipid with residual standard deviation of 1.9%. In validating any of these methods, account should be take of the extent to which the information they give can augment that given by more simple measures like age and weight.
{"AnatomicalEntity": ["body", "adipose tissue", "tissue", "subcutaneous adipose tissue", "bone", "abdominal adipose tissue", "muscle"]}