Frameless stereotactic radiosurgery of a solitary liver metastasis using active breathing control and stereotactic ultrasound.
OBJECTIVE
Radiosurgery of liver metastases is effective but a technical challenge due to respiration-induced movement. The authors report on the initial experience of the combination of active breathing control (ABC) with stereotactic ultrasound (B-mode acquisition and targeting [BAT]) for frameless radiosurgery.


METHODS
A patient with a solitary, inoperable liver metastasis from cholangiocellular carcinoma is presented (Figure 4). ABC (Figure 3) was used for tumor/liver immobilization. Tumor/liver position was controlled and corrected using ultrasound (BAT; Figure 1). The tumor was irradiated with a single dose of 24 Gy.


RESULTS
Using ABC, the motion of the tumor was significantly reduced and the overall positioning error was < 5 mm (Figure 2). BAT allowed a rapid localization of the lesion during breath hold which could be performed without difficulties for 20 s. Overall treatment time was acceptable (30 min).


CONCLUSIONS
Frameless stereotactic radiotherapy with the combination of ABC and BAT allows the delivery of high single doses to targets accessible to ultrasound with high precision comparable to a frame-based approach.
Boda-Heggemann
Judit
J
Department of Radiation Oncology, Mannheim University Hospital, University of Heidelberg, Mannheim Medical Center, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany. judit.boda-heggemann@radonk.ma.uni-heidelberg.de
Walter
Cornelia
C
Mai
Sabine
S
Dobler
Barbara
B
Dinter
Dietmar
D
Wenz
Frederik
F
Lohr
Frank
F
D000368:Aged; D005500:Follow-Up Studies; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000556:secondary; D008297:Male; D009038:Motion; D011856:Radiographic Image Enhancement; D016634:Radiosurgery / Q000379:methods; D011879:Radiotherapy Dosage; D012119:Respiration; D013238:Stereotaxic Techniques; D013997:Time Factors; D016896:Treatment Outcome; D014463:Ultrasonography