title: Comparison of non-coplanar and coplanar irradiation techniques to treat cancer of the pancreas.
abstract: We compared two different techniques of pancreatic irradiation using measures associated with normal tissue complications. Seven consecutive patients with pancreatic cancer were planned for both coplanar and non-coplanar (NCP) external beam radiation treatments, using the same defined anatomical volumes for each patient, in each case. Each pair of plans was then compared using a range of objective criteria. Individual normal tissues were assessed against traditional tolerance limits. Selected dose-points, normal tissue complication probability (NTCP) and equivalent uniform doses (EUD) were also compared, as were indices combining information from individual tissues - total NTCP and total weighted EUD. All individual normal tissues doses were within established tolerance limits. For NCP relative to coplanar planning, NTCP and EUD were lower for all individual tissues in four cases and one case, respectively, i.e. in most cases a benefit to one tissue was offset by detriment to others. Summary measures demonstrated overall benefits for NCP techniques, with the total NTCP in six patients, and with the total weighted EUD in all patients. NCP techniques show potentially useful benefits. We present a new objective measure, the total weighted EUD, which may be particularly useful comparing plans where there are multiple critical tissues.
authors.affiliation: Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Osborne
authors.forename: S A
authors.initials: SA
authors.lastname: Bydder
authors.forename: M A
authors.initials: MA
authors.lastname: Ebert
authors.forename: N A
authors.initials: NA
authors.lastname: Spry
mesh_terms: D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007668:Kidney / Q000528:radiation effects; D008099:Liver / Q000528:radiation effects; D010190:Pancreatic Neoplasms / Q000532:radiotherapy*; D011829:Radiation Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods*; D013116:Spinal Cord / Q000528:radiation effects