The Objective Measurement of the Lung Parenchyma Motion for Planning Target Volume Delineation

Chung, Weon Kuu; Cho, Jeong Gill

Abstract

PURPOSE
To quantify the movement of lung parenchyma for ICRU 50 Planning Target Volume (PTV) delineation of the lung region.
MATERIALS AND METHODS
Fluoroscopic observations and measurements are performed on 10 patients with chest region cancer who have normal pulmonary functions. We have divided the lung region into 12 parts for the right lung, 10 parts for the left lung and four to five points of lung parenchyma were selected for anatomical analysis points. Fluoroscopic images are sent to a computer and then movements are measured.
RESULTS
Both lower lobes showed the longest longitudinal movements because of breathing (average 14.1mm, maximum 22.1mm), while antero- posterior displacement showed the smallest value. Lateral movements of the lung parenchyma averaged 6.6mm, and the maximum value was 9.1mm. (both hilar regions showed maximum values because of cardiac motion)
CONCLUSION
We could quantify the lung movements by measuring parenchyma displacements. The movements of both upper lobes were less than those of the middle and upper lobes in longitudinal and transverse movements. Optimal margins can be selected for PTV delineation using these results.