Correction of systematic setup errors in prostate radiation therapy: How many images to perform?

Implementing of the offline setup correction protocol in pelvic radiotherapy: safety margins and number of images

“…If the time trend exists, the correction of the systematic error may not be accurate. 11 Time trends were investigated using a linear regression approach and the existence of time trends was considered if the slope was greater than 4 mm during the treatment. This limit was used to avoid too many patients to be excluded from the study.…”

“…[10][11][12] The systematic error for the entire group (SEeg) was defined as the arithmetic mean of all patients' systematic errors. The random deviation of the patients' SE from SEeg was estimated by 1 SD (SDse).…”

“…The systematic error is the main factor when considering the margin size to account for setup uncertainties. [10][11][12] When correcting the patient position, only the systematic component of the setup error must be corrected. 8,11,12 The purpose of this study was to investigate the accuracy of daily patient positioning in our department in the bellyboard pelvis radiotherapy.…”

“…[10][11][12] When correcting the patient position, only the systematic component of the setup error must be corrected. 8,11,12 The purpose of this study was to investigate the accuracy of daily patient positioning in our department in the bellyboard pelvis radiotherapy. Since our department is not equipped with EPID, we chose to implement strategy called no action level (NAL) protocol for reducing patient setup errors.…”

Einfluss von bildgestützter translatorischer Isozentrumskorrektur auf die Dosisverteilung bei 3-D-Konformationsbestrahlung der Prostata

“…Die Gründe für eine Fehlpositionierung der Zielstrukturen bei der Prostatastrahlentherapie sind hauptsächlich die inter-bzw. intrafraktionäre Beweglichkeit der Prostata im Becken [8,30] und Lagerungsfehler [1,19]. Die Bewegung der Prostata wird hauptsächlich durch ein sich in der Ausdehnung änderndes Rektum und in geringerem Maße durch eine sich verändernde Blasenfüllung verursacht [20,24,25,27,[29][30][31][32].…”