Commissioning and first clinical application of mARC treatment.
BACKGROUND
The modulated arc (mARC) technique has recently been introduced for Siemens ARTISTE linear accelerators. We present the first experiences with the commissioning of the system and first patient treatments.


METHODS
Treatment planning and delivery are presented for the Prowess Panther treatment planning system or, alternatively, an in-house code. Dosimetric verification is performed both by point dose measurements and in 3D dose distribution.


RESULTS
Depending on the target volume, one or two arcs can be used to create highly conformal plans. Dosimetric verification of the converted mARC plans with step-and-shoot plans shows deviations below 1 % in absolute point dose; in the 3D dose distribution, over 95 % of the points pass the 3D gamma criteria (3 % deviation in local dose and 3 mm distance to agreement for doses > 20 % of the maximum). Patient specific verification of the mARC dose distribution with the calculations has a similar pass rate. Treatment times range between 2 and 5 min for a single arc.


CONCLUSIONS
To our knowledge, this is the first report of clinical application of the mARC technique. The mARC offers the possibility to save significant amounts of time, with single-arc treatments of only a few minutes achieving comparable dose distribution to IMRT plans taking up to twice as long.
Klinik für Strahlentherapie und Radioonkologie, Universitätsklinikum des Saarlandes, Kirrberger Straße Geb. 6.5, 66421, Homburg, Saarland, Germany, yvonne.dzierma@uks.eu.
Yvonne
Y
Dzierma
Frank G
FG
Nuesken
Stephanie
S
Kremp
Jan
J
Palm
Norbert P
NP
Licht
Christian
C
Rübe
D004867:Equipment Design / Q000592:standards; D019544:Equipment Failure Analysis / Q000592:standards; D005858:Germany; D006801:Humans; D008297:Male; D010315:Particle Accelerators / Q000295:instrumentation* / Q000592:standards*; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000592:standards*; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation* / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity