title: Clinical implications of the ISC technique for breast cancer radiotherapy and comparison with clinical recommendations.
abstract: OBJECTIVE
  The present project studied the implications of using the irregular surface compensator (ISC) technique in comparison to three-dimensional conformal radiation therapy (3D-CRT) for breast cancer treatment. ISC is an electronic compensation algorithm that modulates the fluence across the radiation fields to compensate for irregularly-shaped surfaces and deliver a homogeneous dose to a compensation plane.
  
  
  METHODS
  Ten breast cancer patients (five left- and five right-sided) were planned with both techniques. The planning was done for 50 Gy in 25 fractions with 2 Gy per fraction in all patients. Physical parameters such as doses to the clinical target volume (CTV-T) and the planned target volume (PTV), heterogeneity index and doses to lung and heart were determined and compared for the treatment plans.
  
  
  RESULTS
  The ISC technique led to significantly better coverage of the CTV-T and PTV in almost all patients with statistically significant better homogeneity of the dose distribution. The contralateral lung and the heart receive the same dose with both ISC and 3D-CRT plans. However, ISC showed a trend towards decreasing the volumes of the ipsilateral lung irradiated with high doses.
  
  
  CONCLUSIONS
  The ISC technique leads to an improvement of the target coverage and the radiation burden of the ipsilateral lung thus allowing better compliance with the national recommendations for breast radiotherapy and increasing the potential for improved quality of life for breast cancer patients. It should therefore be preferred over 3D-CRT for breast cases with difficult dose homogeneity to the PTV or CTV-T.
authors: Department of Oncology and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden Anna.Maria.Flejmer@lio.se.
authors: Anna M
authors: AM
authors: Flejmer
authors: Department of Radiation Physics and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
authors: Dan
authors: D
authors: Josefsson
authors: Futurum - Academy for Health and Care, County Council of Jönköping, Jönköping, Sweden.
authors: Mats
authors: M
authors: Nilsson
authors: Futurum - Academy for Health and Care, County Council of Jönköping, Jönköping, Sweden.
authors: Margaretha
authors: M
authors: Stenmarker
authors: Department of Radiation Physics and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
authors: Alexandru
authors: A
authors: Dasu
mesh_terms: D000465:Algorithms; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D017410:Practice Guidelines as Topic; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods* / Q000592:standards; D020266:Radiotherapy, Conformal; D061089:Radiotherapy, Image-Guided
keywords: Breast radiotherapy; fractionated radiotherapy; irradiation technique; irregular surface compensator