Evaluation of the effectiveness of the stereotactic body frame in reducing respiratory intrafractional organ motion using the real-time tumor-tracking radiotherapy system.
OBJECTIVE
To evaluate the effectiveness of the stereotactic body frame (SBF), with or without a diaphragm press or a breathing cycle monitoring device (Abches), in controlling the range of lung tumor motion, by tracking the real-time position of fiducial markers.


METHODS
The trajectories of gold markers in the lung were tracked with the real-time tumor-tracking radiotherapy system. The SBF was used for patient immobilization and the diaphragm press and Abches were used to actively control breathing and for self-controlled respiration, respectively. Tracking was performed in five setups, with and without immobilization and respiration control. The results were evaluated using the effective range, which was defined as the range that includes 95% of all the recorded marker positions in each setup.


RESULTS
The SBF, with or without a diaphragm press or Abches, did not yield effective ranges of marker motion which were significantly different from setups that did not use these materials. The differences in the effective marker ranges in the upper lobes for all the patient setups were less than 1mm. Larger effective ranges were obtained for the markers in the middle or lower lobes.


CONCLUSIONS
The effectiveness of controlling respiratory-induced organ motion by using the SBF+diaphragm press or SBF + Abches patient setups were highly dependent on the individual patient reaction to the use of these materials and the location of the markers. They may be considered for lung tumors in the lower lobes, but are not necessary for tumors in the upper lobes.
Bengua
Gerard
G
Department of Medical Physics, Hokkaido University, Sapporo, Hokkaido, Japan. gerard@med.hokudai.ac.jp
Ishikawa
Masayori
M
Sutherland
Kenneth
K
Horita
Kenji
K
Yamazaki
Rie
R
Fujita
Katsuhisa
K
Onimaru
Rikiya
R
Katoh
Noriwo
N
Inoue
Tetsuya
T
Onodera
Shunsuke
S
Shirato
Hiroki
H
D000368:Aged; D000369:Aged, 80 and over; D003199:Computer Systems; D003964:Diaphragm; D005260:Female; D006046:Gold; D006801:Humans; D007103:Immobilization / Q000295:instrumentation*; D008168:Lung; D008175:Lung Neoplasms / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009068:Movement; D019736:Prostheses and Implants; D012119:Respiration; D018709:Statistics, Nonparametric; D013238:Stereotaxic Techniques / Q000295:instrumentation*
D006046:Gold