Abstract
Background:
Automatic Cone-beam computed tomography (CBCT) based image matching for set-up verification is recommended as compared to 2-D match for post-operative local / loco-regional radiotherapy of breast cancer patients by Volumetric Modulated Arc Therapy (VMAT) technique. However, in supine position, off-midline peripheral body Clinical Target Volume (CTV) of unilateral breast cancer patients immobilized on Breast and Lung board of All-in-One (AIO) positioning systemmay necessitate augmented movement of couch in ‘x’ and ‘z’ axis thereby raising the risk of collusion of x-ray sources / detectors system with couch.
Methods and Materials:
VMAT was planned by a pair of partial arc for whole target volume for seven consecutive post-operative breast cancer patients (five post-mastectomy and two post-breast conservation patients). Tattoo based set-up by shift of treatment table in x-, y- and z-axis as determined by Treatment Planning System followed by X-rays with planar image acquisition and online 2-D imaging matching was performed for set-up verification. In-room 360°rotation of x-ray source and detector system of linear accelerator (linac) was performed before x-ray planar image acquisition.
Results:
Completion of 360°rotation in-room of x-ray source and detector system of linacaround the machine iso-centre was not possible in six out of seven patients due to possibility of collusion of gantry with contralateral side of the couch.
Conclusion:
Performing CBCT for generating 3D images for computed tomography (CT) reconstruction may not be practical for patient set-up verification of post-operative radiotherapy of unilateral breast cancer patients positioned supine on breast and lung board.
Assessment of mandibular osseous changes using radiomorphometric indices by cone beam computed tomography in patients with End-stage renal failure versus normal population (Observational Study)