ABSTRACT
Consistent Image Registration and Spirometry .................................................. 97 5.7 Optical Flow-Based Methods ............................................................................................ 97
5.7.1 Nonrigid Registration Method to Assess the Reproducibility of BreathHolding with Active Breathing Control in Lung Cancer ................................... 98
5.7.2 Evaluation of Deformable Registration of Patient Lung 4DCT with Subanatomical Region Segmentations.................................................................. 98
Lungs are essential respiratory organs that supply the human body with oxygen and remove carbon dioxide. Lungs expand and contract during the respiration process, enabling the air to ¸ow inside it. Knowing the lungs’ normal form and how they deform while breathing is an important factor for several different applications. First, a change in the lungs’ normal deformation during breathing is a key indicator of a disease state that the human subject may have. Depending on the type of pathophysical condition, the lung’s shape may change to minimize the work and stress of breathing that may be associated with breathing when representing the condition. For example, it is known that patients with chronic obstructive pulmonary disease tend to have difŽculty breathing and so they alter their breathing pattern to short, shallow breaths that lower the physical stress the subject experiences. Furthermore, patients with disease states such as non-small cell lung cancer tend to develop breathing changes that re¸ect the presence of tumors. Additional complications arise when the patient has multiple disease states, for instance, the presence of non-small cell lung cancer as well as chronic obstructive pulmonary disease. Based on the type of treatment or therapy the patient is undergoing, the knowledge of the lung’s change in shape becomes essential. Second, knowledge of lung motion is essential for understanding the preoperative and postoperative changes in lung functionality. For instance, when patients undergo procedures such as thorectomy or lung transplant, it becomes necessary to monitor the lung’s changes in pulmonary function before and after the procedure to understand the functionality of the new anatomy. Third, when patients experience a lung injury, it is vital to the patient’s course of treatment to know the changes in the lung’s breathing functionality. A vast amount of research has been undertaken to better understand the changes in the respiration process when military service personnel receive shrapnel and bullet wounds. A common injury faced by the subject is open and closed (tension) pneumothorax [1]. In the case of open pneumothorax, the subject has an
5.8 Validation, the Much Needed Emphasis ..........................................................................99 5.8.1 Deformable 4DCT Lung with Vessel Bifurcations ..............................................99 5.8.2 Validation Using 3D Lung Phantom .....................................................................99 5.8.3 Validation Using Root Mean Square Error ..........................................................99 5.8.4 Validation Using Regression ................................................................................ 100 5.8.5 Validation and Comparison Methods for Free-Breathing 4D Lung CT ........ 100
5.9 Lung Radiotherapy ............................................................................................................ 101 5.9.1 Simulation and Visualization Requirements for Lung Radiotherapy ........... 102 5.9.2 Development of Physics-Based Deformable Lung Models from 4DCT
Lung Registration .................................................................................................. 102 5.9.2.1 Physics-Based 3D Deformable Lung Surface Model .......................... 102 5.9.2.2 3D Lung Surface Deformations for PET/CT Image Registration ..... 103 5.9.2.3 Physics-Based Volumetric 3D Lung Model ......................................... 103 5.9.2.4 Application of Lung Deformation Estimated from 4DCT for
Lung Radiotherapy Applications .......................................................... 104 5.10 Conclusions ......................................................................................................................... 106 Acknowledgments ...................................................................................................................... 106 References ..................................................................................................................................... 107
open wound that Žlls the pleural cavity with air, disrupting the body’s normal system for maintaining a dynamic air volume-pressure relation that enables respiration. The lungs will shrink, unable to respond to the additional air pressure from the open wound and thus disabling them from expanding and contracting after a few breaths. In the case of closed pneumothorax, the subject has a closed wound that Žlls the pleural cavity with a constant amount of air. The presence of air in the pleural cavity causes constant pain and discomfort to the patient during breathing. The common treatment method involves placing a needle in the chest and removing the air from the pleural cavity. It is important to assess the efŽcacy and success of the treatment using preoperative (initial or base level lung functionality) and postoperative breathing comparison.
