Purpose
Accurate estimation for the effects of respiratory motion can potentially lead to more accurate diagnosis and treatment. In radiation therapy, for example, the motion is assessed for determination of planning margins1) and delivered dose assessment2). Although the respiratory motion has been modeled in a variety of ways for different purposes, the effects of different breathing maneuvers are not well known.
Respiration is generally divided into abdominal breathing and thoracic breathing. (Fig. 1, Fig. 2 ) The muscles used in abdominal breathing are the diaphragm for...
Methods and materials
Patients
Ten left-sided post lumpectomy patients who underwent free-breathing (FB) CT, abdominal deep inspiration breath-hold (AB) CT, and thoracic deep inspiration breath-hold (TB) CT for breast-conserving radiation therapy were as retrospectively evaluated. The coaching session for using abdominal breathing and thoracic breathing properly was carried out before the CT scan and lasted about 10 minutes. All patients were positioned on a supine breast board with arms extended above their head in supports.
Anatomic characteristics (edge measurements)
To investigate anatomic characteristics between ABCT and TBCT, lung...
Results
Anatomic characteristics
Average lung volume was 2279㎤ for free-breathing (FB) CT, 3677㎤ for abdominal breathing (AB) CT, and 3709㎤ for thoracic breathing (TB)CT. Although lung volume increased significantly during AB and TB compared with FB, no significant differences were observed in lung volume between AB and TB.
Fig. 4shows the lung expansion rate from FB to AB and TB. The intrathoracic AP expansion rate of TB was significantly larger than AB, and CC distance of AB was significantly larger than TB.
Quantitative evaluation of lung...
Conclusion
We evaluated lung motion due to different breathing maneuvers using DIR. The lung motion and deformation in abdominal and thoracic breathing showed similar trends in both DIR and edge measurements. The abdominal breathing yielded lung deformation and motion predominantly in the inferior direction. The thoracic breathing yielded lung deformation and motion predominantly in the anterior direction. The motion evaluation using DIR can quantitatively evaluate the motion and deformation of the whole lung in more detail than the simple organ motion evaluation method based on the...
Personal information and conflict of interest
S. Maehira; Kanagawa/JP - nothing to disclose T. Hiroki; Kanagawa/JP - nothing to disclose Y. Fujita; Tokyo/JP - nothing to disclose K. Usui; Tokyo/JP - nothing to disclose E. Kunieda; Kanagawa/JP - nothing to disclose
References
1) VAN HERK, Marcel. Errors and margins in radiotherapy. In: Seminars in radiation oncology. WB Saunders, 2004. p. 52-64.
2) CAI, Weixing, et al. 3D delivered dose assessment using a 4DCT‐based motion model. Medical physics, 2015, 42.6Part1: 2897-2907.
3) PLATHOW, Christian, et al. Influence of different breathing maneuvers on internal and external organ motion: use of fiducial markers in dynamic MRI. International Journal of Radiation Oncology* Biology* Physics, 2005, 62.1: 238-245.
4)KEALL, Paul J., et al. The management of respiratory motion in radiation oncology report...