COMPUTERIZED TOMOGRAPHY (CT) FLUOROSCOPY IMAGING SYSTEM USING A STANDARD INTENSITY CT SCAN WITH REDUCED INTENSITY CT SCAN OVERLAYS

1 . A method for providing CT fluoroscopy of an internal procedure site during a medical procedure so as to visualize patient anatomy and a high-contrast medical element during the medical procedure without subjecting the patient to unacceptable quantities of X-ray radiation, the method comprising:

(1) taking a standard intensity CT scan of the internal procedure site;

(2) taking a reduced intensity CT scan of the internal procedure site while the high-contrast medical element is inserted into the internal procedure site;

(3) extracting the high-contrast medical element portion of the reduced intensity CT scan from the reduced intensity CT scan taken in Step 2;

(4) merging the high-contrast medical element portion of the reduced intensity CT scan extracted in Step 3 with the standard intensity CT scan of the internal procedure site taken in Step 1 so as to provide a composite CT scan;

(5) displaying the composite CT scan generated in Step 4; and

(6) returning to either Step 1 or Step 2.

2 . A method according to claim 1 wherein the standard intensity CT scan is taken at an X-ray intensity level of approximately 300 mAs.

3 . A method according to claim 1 wherein the reduced intensity CT scan is taken at an X-ray intensity level of approximately 15-30 mAs.

4 . A method according to claim 1 wherein the internal procedure site is scanned multiple times with a reduced intensity CT scan for each time the internal procedure site is scanned with a standard intensity CT scan.

5 . A method according to claim 1 wherein the internal procedure site is scanned with a reduced intensity CT scan approximately 10 times as often as the internal procedure site is scanned with a standard intensity CT scan.

6 . A method according to claim 1 wherein the high-contrast medical element comprises one from the group consisting of medical instruments, prostheses, catheters, needles and injectable substances.

7 . Apparatus for providing CT fluoroscopy of an internal procedure site during a medical procedure so as to visualize patient anatomy and a high-contrast medical element during the medical procedure without subjecting the patient to unacceptable quantities of X-ray radiation, the apparatus comprising:

a CT machine configured to:

(1) take a standard intensity CT scan of the internal procedure site;

(2) take a reduced intensity CT scan of the internal procedure site while the high-contrast medical element is inserted into the internal procedure site;

(3) extract the high-contrast medical element portion of the reduced intensity CT scan from the reduced intensity CT scan taken in Step 2;

(4) merge the high-contrast medical element portion of the reduced intensity CT scan extracted in Step 3 with the standard intensity CT scan of the internal procedure site taken in Step 1 so as to provide a composite CT scan;

(5) display the composite CT scan generated in Step 4; and

(6) return to either Step 1 or Step 2.

8 . Apparatus according to claim 7 wherein the standard intensity CT scan is taken at an X-ray intensity level of approximately 300 mAs.

9 . Apparatus according to claim 7 wherein the reduced intensity CT scan is taken at an X-ray intensity level of approximately 15-30 mAs.

10 . A method according to claim 7 wherein the internal procedure site is scanned multiple times with a reduced intensity CT scan for each time the internal procedure site is scanned with a standard intensity CT scan.

11 . Apparatus according to claim 7 wherein the internal procedure site is scanned with a reduced intensity CT scan approximately 10 times as often as the internal procedure site is scanned with a standard intensity CT scan.

12 . Apparatus according to claim 7 wherein the high-contrast medical element comprises one from the group consisting of medical instruments, prostheses, catheters, needles and injectable substances.