This study will evaluate the accuracy and effectiveness of an experimental tracking device for locating abnormalities during invasive procedures, such as biopsy or ablation, that cannot easily be visualized by usual imaging techniques, such as computed tomography (CT) scans or ultrasound. Some lesions, such as certain liver or kidney tumors, small endocrine abnormalities, and others, may be hard to find or only visible for a few seconds. The new method uses a needle with a miniature tracking device buried inside the metal that tells where the tip of the needle is located, somewhat like a mini GPS, or global positioning system. It uses a very weak magnet to localize the device like a miniature satellite system. This study will explore whether this system can be used in the future to more accurately place the needle in or near the desired location or abnormality.

Patients 18 years of age and older who have a lesion that needs to be biopsied or an ablation procedure that requires CT guidance may be eligible for this study. Candidates are screened with a medical history and review of medical records, including imaging studies.

Participants undergo the biopsy or ablation procedure as they normally would, with the following exceptions: some stickers are placed on the skin before the procedure and a very weak magnet is placed nearby. The needles used are similar to the ones that would normally be used except that they contain a metal coil or spring buried deep within the needle metal. The procedure involves the following steps:

1. Small 1-cm plastic donuts are place on the skin with tape.

2. A planning CT scan is done.

3. The CT scan is sent to the computer and matched to the patient's body location with the help of a very weak magnet.

4. The needle used for the procedure is placed towards the target tissue or abnormality and the "smart needle" location lights up on the old CT scan.

5. A repeat CT is done as it normally is to look for the location of the needle.

6. After the procedure the CT scans are examined to determine how well the new tool located the needle in the old scan.

Further Study Details: 

Expected Total Enrollment:  20

This study will examine the use of a guidance system for navigating and monitoring devices like biopsy and ablation needles for localization in relation to pre-operative images like contrast-enhanced CT scan. Pre-procedural contrast enhanced CT scan will be aligned and matched to the patient and then to the spatial coordinates of a needle. We will use a commercial weak magnetic field generator combined with biocompatible interventional needles. These needles have a very small sensor coil buried within the metal that can be localized within this magnetic field. The coil never touches the patient and cannot come off the needle. An insulated wire runs from the needle to the computer. Custom software will be used to analyze the signal sent by the devices to localize the devices within a pre-operative reference imaging set (contrast enhanced CT scan). The software will be the same that we have used extensively in phantoms and in animals, and displays a graphical user interface that shows the device location within the pre-operative imaging data set. Similar systems have been routinely used in neurosurgery and otolaryngology for many years for similar purposes, but these tracking systems have not been widely applied to needle based procedures to date. Such navigation systems have traditionally relied upon infrared or optical signals for localization, instead of electromagnetics. Such systems could dramatically improve the way that devices are tracked while inside the body, and allow direct use of pre-operative images, instead of relying upon the operator's spatial awareness and "mental model building".

Genders Eligible for Study:  Both

Criteria

INCLUSION CRITERIA:
Patients must fulfill all of the following criteria to be eligible for study admission:
All patients must have a pre-operative CT scan or PET scan performed at NIH. Patients must either have a lesion needing biopsy or ablation requiring CT scan guidance.
Age greater than 18 years.
No serious concurrent medical illness that would preclude the patient from making a rational informed decision on participation.
The ability to understand and willingness to sign a written informed consent form, and to comply with the protocol. If in question, an ethics consult will be obtained.
Ability to hold breath (if procedure to be performed with conscious sedation, and without general anesthesia).
Patients must be actively enrolled on an NIH protocol and be scheduled for a CT guided biopsy.
EXCLUSION CRITERIA:
Patients with any of the following will be excluded from study entry:
Patients with an altered mental status that precludes understanding or consenting for the biopsy procedure will be excluded from this study.
Patients unlikely able to hold reasonably still on a procedure table for the length of the procedure.
Patients with any known allergy to adhesives or latex or skin reactions to dressings (since the adhesive fiducials could theoretically induce a rash in these patients).
Inability to hold breath, if procedure will be performed with conscious sedation, and without general anesthesia.
Patients with pacemakers or automatic implatable cardiac defibrillators.
Gross body weight above the CT table limit (375 pounds).
Pregnancy.

Maryland
      Warren G. Magnuson Clinical Center (CC), 9000 Rockville Pike,  Bethesda,  Maryland,  20892,  United States; Recruiting

Study ID Numbers:  050091; 05-CC-0091
Record last reviewed:  January 21, 2005
Last Updated:  March 5, 2005
Record first received:  January 29, 2005
ClinicalTrials.gov Identifier:  NCT00102544
Health Authority: United States: Federal Government
ClinicalTrials.gov processed this record on 2005-04-08