title: High definition three-dimensional ultrasound to localise the tumour bed: a breast radiotherapy planning study.
abstract: OBJECTIVE
  Complex radiation techniques, such as conformal radiotherapy for partial breast irradiation, require accurate localisation of the tumour bed. This study investigated high definition 3D ultrasound for breast tumour bed localisation. Study aims were: firstly, to determine how easily a tumour cavity could be visualised with 3D ultrasound; secondly, to determine the accuracy of computed tomography (CT) and 3D ultrasound co-registration; thirdly, to compare 3D ultrasound with other methods of localisation.
  
  
  METHODS
  3D ultrasound examinations were carried out in 40 women attending for breast radiotherapy. 3D position data were co-registered with the radiotherapy planning CT. 2D ultrasound and CT, surgical clips and CT, and CT alone were also used to localise the tumour bed in 32/40, 14/40 and 5/40 patients, respectively. Tumour bed volume and centre of gravity measurements for all methods of localisation were compared.
  
  
  RESULTS
  Mean surgery to imaging interval was 44 days (range 23-86 days). The post-operative cavity was seen in all cases using the 3D ultrasound, and was graded as highly visible, visible and subtle in 21/40 (53%), 12/40 (30%) and 7/40 (17%) cases, respectively. There was a statistically significant improvement in the ability of 3D ultrasound to localise the tumour bed compared with 2D ultrasound. CT-ultrasound registration was achieved in all cases. Two-dimensional and 3D ultrasound showed smaller tumour bed volumes than clips.
  
  
  CONCLUSIONS
  Three-dimensional ultrasound localisation of the tumour bed appears superior to 2D ultrasound. It can also be co-registered with a planning CT, thus allowing additional information on the size and location of the tumour bed to be integrated into complex radiotherapy planning.
authors: Department of Oncology, Cambridge University, UK. charlotte.coles@addenbrookes.nhs.uk
authors: Charlotte E
authors: CE
authors: Coles
authors: Charlotte J C
authors: CJ
authors: Cash
authors: Graham M
authors: GM
authors: Treece
authors: Fiona N A C
authors: FN
authors: Miller
authors: Andrew C F
authors: AC
authors: Hoole
authors: Andrew H
authors: AH
authors: Gee
authors: Richard W
authors: RW
authors: Prager
authors: Ruchi
authors: R
authors: Sinnatamby
authors: Peter
authors: P
authors: Britton
authors: Jenny S
authors: JS
authors: Wilkinson
authors: Anand D
authors: AD
authors: Purushotham
authors: Neil G
authors: NG
authors: Burnet
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D006801:Humans; D019047:Phantoms, Imaging; D011880:Radiotherapy Planning, Computer-Assisted; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography