title: Tumor control probability for selective boosting of hypoxic subvolumes, including the effect of reoxygenation.
abstract: OBJECTIVE
  To study the effect on tumor control probability of selectively boosting the dose to hypoxic subvolumes.
  
  
  METHODS
  A Monte Carlo model was developed that separates the tumor into two compartments, one of which receives a primary dose, and one of which receives a higher boost dose. During radiation delivery, each compartment consists of three clonogen subpopulations: those that are well oxygenated, those that are temporarily hypoxic (geometrically transient hypoxia), and those that are permanently hypoxic (geometrically stable hypoxia). The spatial location of temporary hypoxia within the tumor volume varies over time, whereas, the spatial location of permanent hypoxia does not. The effect of reoxygenation was included. Clonogen proliferation was not included in the model.
  
  
  RESULTS
  A modest boost dose (120%-150% of the primary dose) increases tumor control probability to that found in the absence of permanent hypoxia. The entire hypoxic subvolume need not be included to obtain a significant benefit. However, only tumors with a geometrically stable hypoxic volume will have an improved control rate.
  
  
  CONCLUSIONS
  Tumors with an identifiable geometrically stable hypoxic volume will have an improved control rate if the dose to the hypoxic volume is escalated. Further work is required to determine the spatiotemporal evolution of the hypoxic volumes before and during the course of radiotherapy.
authors.affiliation: Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, USA. rpopple@uabmc.edu
authors.forename: Richard A
authors.initials: RA
authors.lastname: Popple
authors.forename: Roger
authors.initials: R
authors.lastname: Ove
authors.forename: Sui
authors.initials: S
authors.lastname: Shen
mesh_terms: D000465:Algorithms; D015687:Cell Hypoxia / Q000502:physiology*; D006801:Humans; D009010:Monte Carlo Method; D009369:Neoplasms / Q000473:pathology / Q000503:physiopathology* / Q000532:radiotherapy*; D010100:Oxygen / Q000008:administration & dosage*; D011836:Radiation Tolerance / Q000502:physiology*; D011879:Radiotherapy Dosage
chemical_list: D010100:Oxygen