Accuracy of single-session extracranial radiotherapy for simple shaped lung tumor or metastasis using fast 3-D CT treatment planning.
BACKGROUND
This study is situated in the area of measuring set-up accuracy and time periods of single-session extracranial radiotherapy (SSRT) for simple-shaped targets (e.g., spherical or rotational symmetrical) definitively located in the peripheral lung.


METHODS
After adaptation of the stereotactic body frame, the patient has to remain in the vacuum pillow during planning computed tomography (CT), fast three-dimensional (3-D) treatment planning, and direct irradiation after verification. Fast preplanning is performed by using virtual simulation software to accelerate the method.


RESULTS
In our new procedure, SSRT is applied in approximately 1.5 h. The mean setup accuracy vector was 2.4+/-0.7 mm in the range of 1.34 to 4 mm. Mean intrafractional patient movement in the stereotactic body frame before and after radiation was 0.70 mm+/-0.5 mm and 0.76+/-0.76 mm in the range of 0 to 2.8 mm. Mean time period steps were measured at (1) planning CT with 3-D treatment planning: 76+/-12 min; (2) irradiation and verification: 33+/-7 min; and (3) complete procedure duration: 109+/-11 min (range, 89-169).


CONCLUSIONS
The main difference between the positioning technique of SSRT and that of conventional extracranial radiosurgery is the tighter patient fixation, which guarantees minimal patient movement. The main advantages are procedure acceleration and omission of CT simulation. SSRT is a preliminary stage of real-time treatment.
Strassmann
Gerd
G
Department of Radiation Oncology, University of Marburg, Marburg, Germany. strassma@med.uni-marburg.de
Braun
Isabell
I
Kress
Oliver
O
Richter
Detlef
D
Neidel
Hans Otto
HO
Klose
Klaus Jochen
KJ
An
Hanxiang
H
Vogel
Birgit
B
Rose
Frank
F
Engenhart-Cabillic
Rita
R
D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000532:radiotherapy* / Q000556:secondary; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007103:Immobilization / Q000379:methods; D008175:Lung Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D013238:Stereotaxic Techniques; D014057:Tomography, X-Ray Computed