Removing Respiratory Artifacts in Nuclide Breast Imaging
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Radionuclide imaging is a technique that allows physicians to obtain clear images of metabolically active tissues in the body. To obtain the images, radioactive materials (called “tracers”) are introduced into the patient’s body. The tracers emit gamma rays, which are the basis for detection. Radionuclide imaging holds great potential to non-invasively provide valuable information about breast cancer, including detection, staging, and treatment response. However, the utility of the imaging modality is heavily dependent on the sensitivity and accuracy of the reconstructed images. In breast scans, respiratory motion hinders tumor evaluation by effectively smearing the signal over the respiratory cycle, both lowering the signal-to-noise ratio and distorting the tumor volume.
 
 
 
 
 
 
 
 A key issue in radionuclide imaging is the duration over which the scan must occur to obtain adequate statistics. While patient respiratory motion can be substantially controlled through various means in fast imaging modalities like computed tomography (CT), the several minutes required in PET scans severely hinders any possibility of respiratory control. Furthermore, any method which relies on partial signal acquisition (e.g., at end-inspiration) provides correspondingly less data per respiratory cycle, and consequently requires additional (and possibly unacceptable) scan time. 
 
 
 
 
 
 
 
 We hypothesize that respiratory motion artifacts in breast cancer can be eliminated through specialized acquisition and image processing methods, with minimal or no additional hardware beyond the radionuclide imaging equipment in current clinical use, and without requiring additional scanning time or patient effort. This project consists of three principal aims to achieve the goal of eliminating respiratory motion artifacts in breast cancer radionuclide imaging. The first aim is to construct a method of acquiring and sorting radionuclide data and respiratory motion information, optimally suited for breast cancer imaging. The second aim is to design and implement image processing algorithms that remove respiratory motion artifacts from the radionuclide images. The third aim is to validate these methods on breast cancer patient data. We propose to acquire in small time intervals, a fraction of the respiratory cycle, and then sort according to respiratory phase or amplitude. The sorted images can then be modified to match one another using deformable image registration methods, which permit tissue translation in addition to volume and shape distortion. Finally, stacking the deformed images will generate an image at a single respiratory point, without any loss of scan data. The method will be validated on approximately one dozen breast cancer patients enrolled in imaging and treatment protocols at the Stanford Hospital.
 
 
 
 
 
 
 
 Because radionuclide scans are noninvasive, they are an attractive alternative to multiple biopsies in initial evaluation of tumor volume and stage. In addition, several treatment alternatives are readily available for breast cancer, and it would prove invaluable to develop reliable correlations between radionuclide scan information and treatment response at early stages of the treatment. Finally, accurate evaluation of the extent of the cancer, particularly for ductal carcinoma in situ, could make the difference between a lumpectomy and a radical mastectomy. Elimination of respiratory motion artifacts will permit the best possible realization of these potential achievements of radionuclide imaging.