title: Inverse treatment planning for spinal robotic radiosurgery: an international multi-institutional benchmark trial.
abstract: Stereotactic radiosurgery (SRS) is the accurate, conformal delivery of high-dose radiation to well-defined targets while minimizing normal structure doses via steep dose gradients. While inverse treatment planning (ITP) with computerized optimization algorithms are routine, many aspects of the planning process remain user-dependent. We performed an international, multi-institutional benchmark trial to study planning variability and to analyze preferable ITP practice for spinal robotic radiosurgery. 10 SRS treatment plans were generated for a complex-shaped spinal metastasis with 21 Gy in 3 fractions and tight constraints for spinal cord (V14Gy < 2 cc, V18Gy < 0.1 cc) and target (coverage > 95%). The resulting plans were rated on a scale from 1 to 4 (excellent-poor) in five categories (constraint compliance, optimization goals, low-dose regions, ITP complexity, and clinical acceptability) by a blinded review panel. Additionally, the plans were mathemati-cally rated based on plan indices (critical structure and target doses, conformity, monitor units, normal tissue complication probability, and treatment time) and compared to the human rankings. The treatment plans and the reviewers' rankings varied substantially among the participating centers. The average mean overall rank was 2.4 (1.2-4.0) and 8/10 plans were rated excellent in at least one category by at least one reviewer. The mathematical rankings agreed with the mean overall human rankings in 9/10 cases pointing toward the possibility for sole mathematical plan quality comparison. The final rankings revealed that a plan with a well-balanced trade-off among all planning objectives was preferred for treatment by most par-ticipants, reviewers, and the mathematical ranking system. Furthermore, this plan was generated with simple planning techniques. Our multi-institutional planning study found wide variability in ITP approaches for spinal robotic radiosurgery. The participants', reviewers', and mathematical match on preferable treatment plans and ITP techniques indicate that agreement on treatment planning and plan quality can be reached for spinal robotic radiosurgery.
authors.affiliation: University Medical Center Schleswig-Holstein; Saphir Radiosurgery Cente. oliver@blanck.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Blanck
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Baus
authors.forename: Jimm
authors.initials: J
authors.lastname: Grimm
authors.forename: Thomas
authors.initials: T
authors.lastname: Lacornerie
authors.forename: Joakim
authors.initials: J
authors.lastname: Nilsson
authors.forename: Sergii
authors.initials: S
authors.lastname: Luchkovskyi
authors.forename: Isabel Palazon
authors.initials: IP
authors.lastname: Cano
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Shou
authors.forename: Myriam
authors.initials: M
authors.lastname: Ayadi
authors.forename: Harald
authors.initials: H
authors.lastname: Treuer
authors.forename: Romain
authors.initials: R
authors.lastname: Viard
authors.forename: Frank-Andre
authors.initials: FA
authors.lastname: Siebert
authors.forename: Mark K H
authors.initials: MK
authors.lastname: Chan
authors.forename: Guido
authors.initials: G
authors.lastname: Hildebrandt
authors.forename: Jürgen
authors.initials: J
authors.lastname: Dunst
authors.forename: Detlef
authors.initials: D
authors.lastname: Imhoff
authors.forename: Stefan
authors.initials: S
authors.lastname: Wurster
authors.forename: Robert
authors.initials: R
authors.lastname: Wolff
authors.forename: Pantaleo
authors.initials: P
authors.lastname: Romanelli
authors.forename: Eric
authors.initials: E
authors.lastname: Lartigau
authors.forename: Robert
authors.initials: R
authors.lastname: Semrau
authors.forename: Scott G
authors.initials: SG
authors.lastname: Soltys
authors.forename: Achim
authors.initials: A
authors.lastname: Schweikard
mesh_terms: D000465:Algorithms; D019985:Benchmarking; D006801:Humans; D007390:International Agencies; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods; D012371:Robotics / Q000379:methods*; D013125:Spinal Neoplasms / Q000601:surgery*