Real-time tumor-tracking radiotherapy for adrenal tumors.
OBJECTIVE
To investigate the three-dimensional movement of internal fiducial markers near the adrenal tumors using a real-time tumor-tracking radiotherapy (RTRT) system and to examine the feasibility of high-dose hypofractionated radiotherapy for the adrenal tumors.


METHODS
The subjects considered in this study were 10 markers of the 9 patients treated with RTRT. A total of 72 days in the prone position and 61 treatment days in the supine position for nine of the 10 markers were analyzed. All but one patient were prescribed 48 Gy in eight fractions at the isocenter.


RESULTS
The average absolute amplitude of the marker movement in the prone position was 6.1+/-4.4 mm (range 2.3-14.4), 11.1+/-7.1 mm (3.5-25.2), and 7.0+/-3.5 mm (3.9-12.5) in the left-right (LR), craniocaudal (CC), and anterior-posterior (AP) directions, respectively. The average absolute amplitude in the supine position was 3.4+/-2.9 mm (0.6-9.1), 9.9+/-9.8 mm (1.1-27.1), and 5.4+/-5.2 mm (1.7-26.6) in the LR, CC, and AP directions, respectively. Of the eight markers, which were examined in both the prone and supine positions, there was no significant difference in the average absolute amplitude between the two positions. No symptomatic adverse effects were observed within the median follow-up period of 16 months (range 5-21 months). The actuarial freedom-from-local-progression rate was 100% at 12 months.


CONCLUSIONS
Three-dimensional motion of a fiducial marker near the adrenal tumors was detected. Hypofractionated RTRT for adrenal tumors was feasible for patients with metastatic tumors.
Katoh
Norio
N
Department of Radiology, Hokkaido University Graduate School of Medicine, Sapporo, Japan. noriowo@radi.med.hokudai.ac.jp
Onimaru
Rikiya
R
Sakuhara
Yusuke
Y
Abo
Daisuke
D
Shimizu
Shinichi
S
Taguchi
Hiroshi
H
Watanabe
Yoshiaki
Y
Shinohara
Nobuo
N
Ishikawa
Masayori
M
Shirato
Hiroki
H
D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D000368:Aged; D019583:Dose Fractionation, Radiation; D005471:Fluoroscopy; D006046:Gold; D006801:Humans; D008297:Male; D008875:Middle Aged; D010315:Particle Accelerators; D016684:Prone Position; D019736:Prostheses and Implants; D011882:Radiotherapy, High-Energy; D014057:Tomography, X-Ray Computed
D006046:Gold