Anne-Marie Frelin-Labalme1,2, Vincent Beaudouin3. 1. 1 Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Boulevard Henri Becquerel, 14076 Caen, France. 2. 2 Advanced Resource Centre for Hadrontherapy in Europe (ARCHADE) Program, Caen, France. 3. 3 CEA, DRF, I2BM, LDM-TEP, GIP Cyceron, Boulevard Henri Becquerel, 14074 Caen, France.
Abstract
OBJECTIVE: Progress made in preclinical radiotherapy makes respiratory gating reachable. Nevertheless, technical means are still needed, as well as accurate investigations of the effect of motion on small animal treatment plans. METHODS: An animal-scaled dynamic phantom (0.3-11.1-mm motion peak-to-peak amplitude, 30-120 cycles per minute) was developed and characterized. It was used to evaluate respiratory monitoring and high resolution imaging (μPET/CT scans). The width and position variations of a fluorine-18 solution were measured for various motions and gating configurations. The phantom was finally used to measure the impact of motion on dose distribution for vertical irradiation using 2.5- and 5-mm collimations. RESULTS: Phantom motions accurately reproduced original waveforms with good rate and amplitude linearity (R2 = 1 and R2 = 0.9995, respectively). µPET/CT acquisitions showed an increase of 92% of the target size caused by a 4.9-mm sine motion and reduced to <12% by gating. Target motion measurements showed consistency better than 18% between modalities. Irradiations showed that motions >0.8 and 1.1 mm (for the 2.5- and 5-mm collimations, respectively) significantly impact dose homogeneity in the target. CONCLUSION: The phantom allowed studying motion in small animal imaging and irradiation. It showed the important impact of motions >2 mm and provided accurate data to improve the management of mobile tumour irradiation. The implementation of gated irradiation, associated with motion-compensated imaging, is currently under progress. Advances in knowledge: Small animal irradiation gating is not yet used in preclinical studies. As few solutions are under development, tools and accurate studies are highly needed.
OBJECTIVE: Progress made in preclinical radiotherapy makes respiratory gating reachable. Nevertheless, technical means are still needed, as well as accurate investigations of the effect of motion on small animal treatment plans. METHODS: An animal-scaled dynamic phantom (0.3-11.1-mm motion peak-to-peak amplitude, 30-120 cycles per minute) was developed and characterized. It was used to evaluate respiratory monitoring and high resolution imaging (μPET/CT scans). The width and position variations of a fluorine-18 solution were measured for various motions and gating configurations. The phantom was finally used to measure the impact of motion on dose distribution for vertical irradiation using 2.5- and 5-mm collimations. RESULTS: Phantom motions accurately reproduced original waveforms with good rate and amplitude linearity (R2 = 1 and R2 = 0.9995, respectively). µPET/CT acquisitions showed an increase of 92% of the target size caused by a 4.9-mm sine motion and reduced to <12% by gating. Target motion measurements showed consistency better than 18% between modalities. Irradiations showed that motions >0.8 and 1.1 mm (for the 2.5- and 5-mm collimations, respectively) significantly impact dose homogeneity in the target. CONCLUSION: The phantom allowed studying motion in small animal imaging and irradiation. It showed the important impact of motions >2 mm and provided accurate data to improve the management of mobile tumour irradiation. The implementation of gated irradiation, associated with motion-compensated imaging, is currently under progress. Advances in knowledge: Small animal irradiation gating is not yet used in preclinical studies. As few solutions are under development, tools and accurate studies are highly needed.
Authors: Nancy L Ford; Hristo N Nikolov; Chris J D Norley; Michael M Thornton; Paula J Foster; Maria Drangova; David W Holdsworth Journal: Med Phys Date: 2005-09 Impact factor: 4.071
Authors: C Chavarrías; J J Vaquero; A Sisniega; A Rodríguez-Ruano; M L Soto-Montenegro; P García-Barreno; M Desco Journal: Phys Med Biol Date: 2008-08-11 Impact factor: 3.609
Authors: Paul J Keall; Gig S Mageras; James M Balter; Richard S Emery; Kenneth M Forster; Steve B Jiang; Jeffrey M Kapatoes; Daniel A Low; Martin J Murphy; Brad R Murray; Chester R Ramsey; Marcel B Van Herk; S Sastry Vedam; John W Wong; Ellen Yorke Journal: Med Phys Date: 2006-10 Impact factor: 4.071
Authors: J Ferlay; E Steliarova-Foucher; J Lortet-Tieulent; S Rosso; J W W Coebergh; H Comber; D Forman; F Bray Journal: Eur J Cancer Date: 2013-02-26 Impact factor: 9.162