title: Real-time tumor-tracking radiotherapy for adrenal tumors.
abstract: 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.
authors.affiliation: Department of Radiology, Hokkaido University Graduate School of Medicine, Sapporo, Japan. noriowo@radi.med.hokudai.ac.jp
authors.forename: Norio
authors.initials: N
authors.lastname: Katoh
authors.forename: Rikiya
authors.initials: R
authors.lastname: Onimaru
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sakuhara
authors.forename: Daisuke
authors.initials: D
authors.lastname: Abo
authors.forename: Shinichi
authors.initials: S
authors.lastname: Shimizu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Taguchi
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Nobuo
authors.initials: N
authors.lastname: Shinohara
authors.forename: Masayori
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
mesh_terms: 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
chemical_list: D006046:Gold