Treatment planning with intensity modulated particle therapy for multiple targets in stage IV non-small cell lung cancer

Abstract

Intensity modulated particle therapy (IMPT) can produce highly conformal plans, but is limited in advanced lung cancer patients with multiple lesions due to motion and planning complexity. A 4D IMPT optimization including all motion states was expanded to include multiple targets, where each target (isocenter) is designated to specific field(s). Furthermore, to achieve stereotactic treatment planning objectives, target and OAR weights plus objective doses were automatically iteratively adapted. Finally, 4D doses were calculated for different motion scenarios. The results from our algorithm were compared to clinical stereotactic body radiation treatment (SBRT) plans. The study included eight patients with 24 lesions in total. Intended dose regimen for SBRT was 24 Gy in one fraction, but lower fractionated doses had to be delivered in three cases due to OAR constraints or failed plan quality assurance. The resulting IMPT treatment plans had no significant difference in target coverage compared to SBRT treatment plans. Average maximum point dose and dose to specific volume in OARs were on average 65% and 22% smaller with IMPT. IMPT could also deliver 24 Gy in one fraction in a patient where SBRT was limited due to the OAR vicinity. The developed algorithm shows the potential of IMPT in treatment of multiple moving targets in a complex geometry.

Clinical necessity of multi-image based (4DMIB) optimization for targets affected by respiratory motion and treated with scanned particle therapy – A comprehensive review

“…Compared to an ITV-based robust (3D) optimization approach, robust 4D MIB optimization has the advantage of including field-specific, motion-induced range changes while operating on the same target for all fields [66]. Therefore, multiple-field optimization with implicitly defined range margins is possible [67], which otherwise requires complex modifications of the ITV representation [68] and/or density replacements. In the following sections, we will review publications that address the performance of 4D MIB optimization in a clinical context.…”

“…For lung cancer patients with multiple lesions, Anderle et al compared PTV-based, non-robust 4D MIB optimized intensity modulated carbon therapy plans with SBRT plans and showed comparable target coverage and reduced OAR dose for the 4D MIB IMPT plans [67]. That study did not perform any robustness evaluation of the plans.…”

Dosimetric evaluation of 4D‐CBCT reconstructed by Simultaneous Motion Estimation and Image Reconstruction (SMEIR) for carbon ion therapy of lung cancer

“…Excellent dose localization for deep‐seated tumors with critical organ dose sparing can be achieved by treating with heavy ions . The additional benefit that carbon ions have, over other charged particles like protons, is an increased biological effectiveness because of dense ionization and the resulting complex DNA damage . Carbon ion treatment can also improve tumor control without increasing toxicity and is considered a radical nonsurgical therapy that achieves high local control rates without severe adverse effects .…”

“…4,5 The additional benefit that carbon ions have, over other charged particles like protons, is an increased biological effectiveness because of dense ionization and the resulting complex DNA damage. 6,7 Carbon ion treatment can also improve tumor control without increasing toxicity 8,9 and is considered a radical nonsurgical therapy that achieves high local control rates without severe adverse effects. 3 Charged particle therapy, especially with carbon ions, is known to be effective for various treatment sites including lung 10 and may even be a safer option than photon SBRT and protons in case of large or central tumors and poor pulmonary function.…”

Particle radiotherapy and molecular therapies: mechanisms and strategies towards clinical applications

“…This issue is interesting for charged particle therapy, because it is easier with Bragg-peak therapy to irradiate multiple lesions in the patient remaining below the tolerance dose for the normal tissue (Ref. 150).…”