title: Utility of single photon emission computed tomography perfusion scans in radiation treatment planning of locally advanced lung cancers.
abstract: OBJECTIVE
  Lung perfusion scan provides a map of the spatial distribution of lung perfusion. This can be used to design radiation portals to spare functional lung (FL), potentially reducing lung toxicity. The purpose of this study was to assess the utility of lung perfusion single photon emission computed tomography (SPECT) in treatment planning for lung cancer patients.
  
  
  METHODS
  Radiotherapy treatment planning computed tomography (CT) scans and SPECT scans of 11 patients of lung cancer suitable for external radiotherapy were co-registered. Conventional treatment plans (anatomic plan) and plans with FL information (functional plan) was generated. The difference in dose volume parameters (V20, V30 and mean lung doses) due to these two plans were compared using Bland-Altman plots.
  
  
  RESULTS
  Functional plans produced a more favorable plan compared with anatomic plan in all except three cases. FL V20 values and FL mean lung dose were reduced for all patients by an average of 5.45 Gy and 7.72 Gy respectively which were statistically significant.
  
  
  CONCLUSIONS
  Lung perfusion scans provide functional information which is not provided by CT scans. SPECT-guidance aids in reducing the dose delivered to highly perfused regions which could reduce the incidence of pneumonitis.
authors.affiliation: Department of Radiotherapy, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Rae Bareilly Road, Lucknow, Uttar Pradesh, India.
authors.forename: Sushma
authors.initials: S
authors.lastname: Agrawal
authors.forename: M Karthick
authors.initials: MK
authors.lastname: Raj
authors.forename: Subhash Chand
authors.initials: SC
authors.lastname: Kheruka
authors.forename: Kj Maria
authors.initials: KM
authors.lastname: Das
authors.forename: Sanjay
authors.initials: S
authors.lastname: Gambhir
keywords: Lung cancer; radiation therapy; single photon emission computed tomography; treatment planning