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Titolo:
Internal organ motion in prostate cancer patients treated in prone and supine treatment position
Autore:
Stroom, JC; Koper, PCM; Korevaaar, GA; van Os, M; Janssen, M; de Boer, HCJ; Levendag, PC; Heijmen, BJM;
Indirizzi:
Univ Rotterdam Hosp, Dr Daniel Den Hoed Canc Ctr, Div Clin Phys, Rotterdam, Netherlands Univ Rotterdam Hosp Rotterdam Netherlands Phys, Rotterdam, Netherlands Univ Rotterdam Hosp, Dr Daniel Den Hoed Canc Ctr, Dept Radiotherapy, NL-3075 EA Rotterdam, Netherlands Univ Rotterdam Hosp Rotterdam Netherlands NL-3075 EA terdam, Netherlands
Titolo Testata:
RADIOTHERAPY AND ONCOLOGY
fascicolo: 3, volume: 51, anno: 1999,
pagine: 237 - 248
SICI:
0167-8140(199906)51:3<237:IOMIPC>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
3-DIMENSIONAL CONFORMAL RADIOTHERAPY; VERIFICATION PROCEDURE; PELVIC RADIOTHERAPY; SEMINAL-VESICLES; IRRADIATION; VARIABILITY; MARGINS; MOVEMENT; ACCURACY; MARKERS;
Keywords:
prostate cancer; planning margin; internal organ motion; conformal radiotherapy; random systematic variation; time trends;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
29
Recensione:
Indirizzi per estratti:
Indirizzo: Stroom, JC Univ Rotterdam Hosp, Dr Daniel Den Hoed Canc Ctr, Div Clin Phys, Rotterdam, Netherlands Univ Rotterdam Hosp Rotterdam Netherlands erdam, Netherlands
Citazione:
J.C. Stroom et al., "Internal organ motion in prostate cancer patients treated in prone and supine treatment position", RADIOTH ONC, 51(3), 1999, pp. 237-248

Abstract

Background and Purpose: To compare supine and prone treatment positions for prostate cancer patients with respect to internal prostate motion and thrrequired treatment planning margins. Materials and methods: Fifteen patients were treated in supine and fifteenin prone position. For each patient, a planning computed tomography (CT) scan was used for treatment planning. Three repeat CT scans were made in weeks 2, 4, and 6 of the radiotherapy treatment. Only for the planning CT scan, laxation was used to minimise the rectal content. For all patients, the clinical target volume (CTV) consisted of prostate and seminal vesicles. Variations in the position of the CTV relative to the bony anatomy in the fourCT scans of each patient were assessed using 3D chamfer matching. The overall variations were separated into variations in the mean CTV position per patient (i.e. the systematic component) and the average 'day-to-day' variation (i.e. the random component). Required planning margins to account for the systematic and random variations in internal organ position and patient set-up were estimated retrospectively using coverage probability matrices. Results: The observed overall variation in the internal CTV position was larger for the patients treated in supine position. For the supine and pronetreatment positions, the random components of the variation along the anterior-posterior axis (i.e, towards the rectum) were 2.4 and 1.5 mm (1 standard deviation (1 SD)), respectively; the random rotations around the left-right axis were 3.0 and 2.9 degrees (1 SD). The systematic components of these motions (1 SD) were larger: 2.6 and 3.3 mw, and 3.7 and 5.6 degrees, respectively. The set-up variations were similar for both treatment positions. Despite the smaller overall variations in CTV position for the patients in prone position, the required planning margin is equal for both groups (about 1 cm except for 0.5 cm in lateral direction) due to the larger impact of the systematic variations. However, significant time trends cause a systematic ventral-superior shift of the CTV in supine position only. Conclusions: For internal prostate movement, it is important to distinguish systematic from random variations. Compared to patients in supine position, patients in prone position had smaller random but somewhat larger systematic variations in the most important coordinates of the internal CTV position. The estimated planning margins to account for the geometrical uncertainties were therefore similar for the two treatment positions. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/03/20 alle ore 00:14:55