Virtual colonoscopy with radiolabeled phospholipid ether analogs
The present invention provides agents and methods for dual modality virtual colonoscopy that gives both anatomical and functional information using hybrid CT/PET scanning. In preferred embodiments, the present invention provides radiolabeled tumor-specific agents and methods for distinguishing benign polyps from malignant tumors. In further embodiments, the present invention provides compositions and methods useful for distinguishing morphological and functional subregions of a selected region of tissue based on relative levels of phospholipid metabolism. Preferred radiolabeled tumor-specific agents are phospholipid ether analogs labeled with a halogen radioisotope. In certain preferred embodiments, the compositions including radiolabeled phospholipid ether analogs have therapeutic actions in addition to functionally identifying malignant tissue.
1. A method of diagnosing cancer in a selected region of the intestinal tract using dual modality virtual colonoscopy in vivo, comprising the steps of:
administering the radiolabeled 18-(4-iodophenyl)-octadecylphosphocholine;
using computed tomography or magnetic resonance imaging to produce a visualization of the three-dimensional morphology of the selected region suspected of having a malignant tissue;
using positron emission tomography or single photon emission tomography to produce a visualization of the distribution of the radioactivity produced by the radiolabeled 18-(4-iodophenyl)-octadecylphosphocholine; and
comparing the visualization of the morphology of the selected region to the visualization of the distribution of the radioactivity produced by the radiolabeled 18-(4-iodophenyl)-octadecylphosphocholine, wherein the presence of radioactivity indicates the malignant tissue.
2. The method of claim 1 wherein the malignant tissue comprises adenocarcinoma cells.
3. The method of claim 1 wherein 18-(4-iodophenyl)-octadecylphosphocholine is radiolabeled with a halogen isotope selected from the group consisting of 123 I, 124 I, 131 I, and mixtures thereof.
4. The method of claim 1 wherein the radiolabeled 18-(4-iodophenyl)-octadecylphosphocholine is a positron emitter.
5. The method of claim 3 wherein the radiolabeled 18-(4-iodophenyl)-octadecylphosphocholine is selected from the group consisting of 123 I-18-(4-iodophenyl)-octadecylphosphocholine, 124 I-18-(4-iodophenyl)-octadecylphosphocholine, 131 I-18-(4-iodophenyl)-octadecylphosphocholine, and mixtures thereof.
6. The method of claim 1 wherein the selected region of the intestinal tract is the colon.
7. The method of claim 1 wherein the step of comparing the visualization of the morphology of the selected region to the visualization of the distribution of the radioactivity produced by the radiolabeled 18-(4-iodophenyl)-octadecylphosphocholine includes the step of producing an image of a three-dimensional structure by the reconstruction of two-dimensional images.
8. The method of claim 1 wherein the step of comparing the visualization of the morphology of the selected region to the visualization of the distribution of the radioactivity produced by the radiolabeled 18-(4-iodophenyl)-octadecylphosphocholine includes the step of superimposing the visualization of the distribution of the radioactivity produced by the radiolabeled 18-(4-iodophenyl)-octadecylphosphocholine on the visualization of the morphology of the selected region.
9. The method of claim 1 , wherein the first technique is computed tomography and the second technique is positron emission tomography.
10. The method of claim 1 , wherein said malignant tissue is colorectal cancer.
11. The method of claim 9 , wherein said malignant tissue is colorectal cancer.