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Titolo:
Analysis and reduction of 3D systematic and random setup errors during thesimulation and treatment of lung cancer patients with CT-based external beam radiotherapy dose planning
Autore:
de Boer, HCJ; De Koste, JRV; Senan, S; Visser, AG; Heijmen, BJM;
Indirizzi:
Univ Rotterdam Hosp, Dr Daniel Den Hoed Canc Ctr, Div Clin Phys, Dept Radiat Oncol, NL-3008 AE Rotterdam, Netherlands Univ Rotterdam Hosp RotterdamNetherlands NL-3008 AE terdam, Netherlands Univ Nijmegen, Joint Ctr Radiat Oncol Arnhem Nijmegen, Nijmegen, Netherlands Univ Nijmegen Nijmegen Netherlands nhem Nijmegen, Nijmegen, Netherlands
Titolo Testata:
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS
fascicolo: 3, volume: 49, anno: 2001,
pagine: 857 - 868
SICI:
0360-3016(20010301)49:3<857:AARO3S>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
RADIATION-THERAPY; VERIFICATION PROCEDURE; PORTAL IMAGES; REPRODUCIBILITY; IMMOBILIZATION; UNCERTAINTIES; IRRADIATION;
Keywords:
setup accuracy; lung cancer; treatment simulation; correction protocol; EPID;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
28
Recensione:
Indirizzi per estratti:
Indirizzo: de Boer, HCJ Univ Rotterdam Hosp, Dr Daniel Den Hoed Canc Ctr, Div Clin Phys, Dept Radiat Oncol, Groene Hilledijk 301,POB 5201, NL-3008 AE Rotterdam,Netherlands Univ Rotterdam Hosp Groene Hilledijk 301,POB 5201 Rotterdam Netherlands NL-3008 AE
Citazione:
H.C.J. de Boer et al., "Analysis and reduction of 3D systematic and random setup errors during thesimulation and treatment of lung cancer patients with CT-based external beam radiotherapy dose planning", INT J RAD O, 49(3), 2001, pp. 857-868

Abstract

Purpose: To determine the magnitude of the errors made in (a) the setup ofpatients with lung cancer on the simulator relative to their intended setup with respect to the planned treatment beams and (b) in the setup of thesepatients on the treatment unit, To investigate how the systematic component of the latter errors can be reduced with an off-line derision protocol for setup corrections. Methods and Materials: For 39 patients with CT planning, digitally-reconstructed radiographs (DRRs) were calculated for anterior-posterior and lateral beams. Retrospectively, the position of the visible anatomy relative to the planned isocenter was compared with the corresponding position on the digitized simulator radiographs using contour match software. The setup accuracy at the treatment unit relative to the simulator setup was measured for 40 patients for at least 5 fractions per patient in 2 orthogonal beams withthe aid of an electronic portal imaging device (EPID), Setup corrections were applied, based on an off-line decision protocol, with parameters derived from knowledge of the random setup errors in the studied patient group. Results: The standard deviations (SD) of the simulator setup errors relative to the CT planning setup in the lateral, longitudinal, and anterior-posterior directions were 4.0, 2.8, and 2.5 mm, respectively. The SD of rotations around the anterior-posterior axis was 1.6 degrees and around the left-right axis 1.3 degrees. The setup error at the treatment unit had a small random component in all three directions (1 SD = 2 mm), The systematic components were larger, particularly in the longitudinal direction (1 SD = 3.6 mm), but were reduced with the decision protocol to 1 SD < 2 mm with, on average, 0.6 setup correction per patient. Conclusion: Setup errors at the simulator, which become systematic errors if the simulation defines the reference setup, were comparable to the systematic setup errors at the treatment unit in case no off-line protocol wouldhave been applied. Hence, the omission of a separate simulation step can reduce systematic errors as efficiently as the application of an off-line correction protocol during treatment. The random errors were sufficiently small to make an off-line protocol feasible, (C) 2001 Elsevier Science Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/07/20 alle ore 18:10:29