Choline presents as a natural compound in a number of foods, and is absorbed through the intestine. After absorption, it is delivered to the blood. From protein building locks, which are contained in plant foods, it can also be produced by the body itself. Choline is involved in the formation of the cell membrane components, the so-called cell membrane phospholipids.

As with many other malignant tumors, there will also be an elevated level of choline in the cells. Radioactive choline (C11-Choline) marked with carbon-11, can therefore in the tumor tissue of the prostate carcinoma be quantified via a nuclear detector and then be depicted by means of a positron emission tomography.  C11-choline differs from natural choline only because of its radioactive marking and does not present any risk for the human organism. 

Positron emission tomography (PET) monitors the biochemical functioning of cells by detecting how they process certain compounds, such as glucose (sugar). Cancer cells metabolize glucose at a much higher level than normal tissues.

The computer tomogram (CT) generates a multiplicity of radiographs and can depict the examined body section in layers. These cross-sectional images or x-ray slices of the area being studied can then be examined on a computer monitor or printed. The CT scan supplies precise data, as to where in the body tumor-like malignant growths occur. The choline-PET delivers supplementing information whether these are cells with elevated choline level of tumor-suspicious areas. 

In order to achieve a reliable image quality, the examination is performed with a combined PET/CT machine.  

Since the 11C-choline-PET/CT procedure is still in its trial phases, the examination should only be performed selectively, such as for patients after a brachytherapy, radiation therapy or prostatectomy with increased PSA levels (PSA recurrence/biochemical recurrence) to exclude lymph node metastasis  (involvement of lymph nodes) and metastization in the inner organs or in the bones.

A special advantage of the PET/CT is the examination of the entire body in one examination procedure, the avoidance of duplicate or multiple examinations, as well as the reduction of radiation exposure, and the expenditure of time.