title: Towards individualised radiotherapy for Stage I seminoma.
abstract: OBJECTIVE
  Adjuvant radiotherapy is currently standard treatment of Stage I seminoma (SOS). The use of computerised tomogram (CT) planning is compared with traditional planning for greater treatment individualisation.
  
  
  METHODS
  Two plans were generated for each of 10 patients: one using traditional rectangular para-aortic fields, and one using conformal fields. The primary target volume compared was the dosimetric coverage of the inferior vena cava and aorta.
  
  
  RESULTS
  The dosimetric analysis of traditional plans showed that they provided reasonable dosimetric coverage of the CTV. However, if 1cm is used for uncertainty based on nodal coverage then the periphery of the PTV could be significantly under-dosed. The CT based plan delivered improved dosimetry to the vessel PTV compared with the traditional field (CT D 95=24.7 Gy, traditional D 95=23.6 Gy, P=0.002). CT-based plans were significantly wider than traditional plans (CT=11.8 cm, traditional=9 cm, P=0.002). The CT plan tended to irradiate relatively small volumes of the kidneys to higher doses.
  
  
  CONCLUSIONS
  Traditional para-aortic fields may deliver suboptimal dosimetry to an anatomically defined PTV. Our CT-based fields tend to be wider than traditional fields, and provide improved dosimetry to vessels based target volumes. Given that traditional fields are often delivering significantly less than the prescribed dose to the target volume, and that marginal relapses cause a high proportion of treatment failure, there is a suggestion that CT-based plans may avoid under-dosage and geographical miss sometimes seen with traditional plans.
authors.affiliation: Radiation Oncology Centre, Austin Health, Vic., Australia. jarad.martin@rmp.uhn.on.ca
authors.forename: Jarad M
authors.initials: JM
authors.lastname: Martin
authors.forename: Daryl Lim
authors.initials: DL
authors.lastname: Joon
authors.forename: Nicole
authors.initials: N
authors.lastname: Ng
authors.forename: Michael
authors.initials: M
authors.lastname: Grace
authors.forename: David Van
authors.initials: DV
authors.lastname: Gelderen
authors.forename: Marita
authors.initials: M
authors.lastname: Lawlor
authors.forename: Morikatsu
authors.initials: M
authors.lastname: Wada
authors.forename: Michael Lim
authors.initials: ML
authors.lastname: Joon
authors.forename: George
authors.initials: G
authors.lastname: Quong
authors.forename: Vincent
authors.initials: V
authors.lastname: Khoo
mesh_terms: D019583:Dose Fractionation, Radiation; D006801:Humans; D008297:Male; D009919:Orchiectomy; D018714:Radiotherapy, Adjuvant; D020266:Radiotherapy, Conformal / Q000379:methods*; D012189:Retrospective Studies; D018239:Seminoma / Q000532:radiotherapy* / Q000601:surgery; D013736:Testicular Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D014057:Tomography, X-Ray Computed