Background: Therapeutic radiation doses of greater than 60Gy may be associated with improved clinical outcomes in patients with lung cancer. However it is generally not possible to deliver a higher dose to the entire Planning Target Volume (PTV) because of dosimetric limitations of normal lung and spinal cord. FDG-PET imaging may help define a sub-volume of the PTV with a greater density of tumour cells that could be irradiated to a higher dose.

Method: For this pilot study ten patients were randomly selected. Patients were planned and treated using the normal departmental protocol to 60Gy. Following treatment, a sub-volume of the PTV was defined representing a volume of intense FDG uptake on PET imaging. An arbitrary threshold of 70% of maximal FDG intensity was used. For the purpose of this study, a hypothetical plan was generated to cover the new PTV with a further 10Gy, using the beam angles of the original treatment plan. Summated Dose Volume Histograms and other dose volume statistics were generated.

Results and Discussion: Results show that additional dose can be given to a small boost volume without significant penalty in terms of the crucial dose limits to Lung, Oesophagus or Spinal cord. Therefore PET imaging may be an appropriate modality for use in defining a boost volume in lung cancer.