Four-dimensional measurement of the displacement of internal fiducial markers during 320-multislice computed tomography scanning of thoracic esophageal cancer.
OBJECTIVE
To investigate the three-dimensional movement of internal fiducial markers placed near esophageal cancers using 320-multislice CT.


METHODS
This study examined 22 metal markers in the esophageal wall near the primary tumors of 12 patients treated with external-beam photon radiotherapy. Motion assessment was analyzed in 41 respiratory phases during 20 s of cine CT in the radiotherapy position.


RESULTS
Motion in the cranial-caudal (CC) direction showed a strong correlation (R(2) > 0.4) with the respiratory curve in most markers (73%). The average absolute amplitude of the marker movement was 1.5 ± 1.6 mm, 1.6 ± 1.7 mm, and 3.3 ± 3.3 mm in the left-right (LR), anterior-posterior (AP), and CC directions, respectively. The average marker displacements in the CC direction between peak exhalation and inhalation for the 22 clips were 1.1 mm (maximum, 5.5 mm), 3.0 mm (14.5 mm), and 5.1 mm (16.3 mm) for the upper, middle, and lower thoracic esophagus, respectively.


CONCLUSIONS
Motion in primary esophagus tumor was evaluated with 320-multislice CT. According to this study, 4.3 mm CC, 1.5 mm AP, and 2.0 mm LR in the upper, 7.4 mm CC, 3.0 mm AP, and 2.4 mm LR in the middle, and 13.8 mm CC, 6.6 mm AP, and 6.8 mm LR in the lower thoracic esophagus provided coverage of tumor motion in 95% of the cases in our study population.
Yamashita
Hideomi
H
Department of Radiology, University of Tokyo Hospital, Tokyo, Japan.
Kida
Satoshi
S
Sakumi
Akira
A
Haga
Akihiro
A
Ito
Saori
S
Onoe
Tsuyoshi
T
Okuma
Kae
K
Ino
Kenji
K
Akahane
Masaaki
M
Ohtomo
Kuni
K
Nakagawa
Keiichi
K
D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging*; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D057918:Fiducial Markers; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009038:Motion; D009068:Movement; D013902:Radiography, Thoracic; D012119:Respiration