AIMS: To assess the set-up uncertainty for gynaecological @entity5 @entity1 treated with external beam radiation therapy using daily kilovoltage image guidance and to estimate set-up margins for treatment and factors that would predict higher set-up uncertainty. MATERIALS AND METHODS: Alignment data from daily two-dimensional kilovoltage planar images and three-dimensional kilovoltage cone beam images for 52 @entity1 treated on a Varian 2300iX linear accelerator with On Board Imaging (OBI; version 1.4) capability were analysed. The mean displacements of translational shifts, population systematic errors and random errors were calculated. Using van Herk's formula, the clinical target volume (CTV) to planning target volume ( @entity343 ) margins for set-up uncertainties were calculated. The differences in set-up error were calculated with respect to the type of @entity5 , imaging type and body mass index (BMI). RESULTS: Population systematic and random errors were 1.1 mm, 2.3 mm, 2.3 mm and 3.9 mm, 5.0 mm, 3.5 mm in the anterior-posterior (AP), medial-lateral (ML) and superior-inferior (SI) directions, respectively, for the entire @entity1 population. Using van Herk's formula, the CTV to @entity343 margins for set-up uncertainties were found to be 5.5, 9.1 and 8.3 mm in the AP, ML and SI directions respectively. The mean displacements in the AP, ML and SI directions for BMI >=  30 (28 @entity1 ) versus <30 (24 @entity1 ) were -0.1 mm, 0.9 mm and 1.0 mm versus -0.1 mm, 0.1 mm and 0.4 mm, respectively, (P = 0.02). CONCLUSIONS: Daily imaging helps to assess set-up uncertainty. The set-up margin for CTV to @entity343 was larger for @entity1 with BMI >=  30 without image guidance and these @entity1 would benefit more from daily image guidance.

Evaluation of set-up uncertainties with daily kilovoltage image guidance in external beam radiation therapy for gynaecological XXXX .

@entity5 :: ('MESH:D009369', 'Disease') :: ['cancer'] @entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity343 :: ('187978', 'Species') :: ['PTV']
@entity5 :: (MESH:D009369,Disease) :: ['cancers']
