Evaluation of a Dynamic Collimation System to Improve IMPT Dose Distributions and Maintain Treatment Efficiency.
Simple Summary: The Dynamic Collimation System (DCS) is a novel, pre-clinical per-spot energy-specific collimator for pencil beam scanning proton therapy that is designed to improve the amount of healthy tissue sparing achieved in low-energy proton therapy treatments. Improved sparing of healthy tis...
| Published in: | Cancers Vol. 18; no. 10; pp. 1573 - 1597 |
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| Main Authors: | , , , , , , , , , , , , |
| Format: | diagnostic images equations & formulas pictorial research tables/charts Journal Article |
| Published: |
MDPI
May2026
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| Online Access: | View this record in EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=194129251&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 194129251 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 20726694 B74B jtl: Cancers issn: 20726694 maglogo: N pubinfo: dt: May2026 vid: 18 iid: 10 pid: 97109 pub: MDPI artinfo: ui: 194129251 194129251 194129251 10.3390/cancers18101573 194129251 ppf: 1573 ppct: 24 formats: tig: atl: Evaluation of a Dynamic Collimation System to Improve IMPT Dose Distributions and Maintain Treatment Efficiency. aug: au: Vu, Nhan Du, Albert Hyer, Daniel E. Gutierrez, Alonso N. Wroe, Andrew Flynn, Ryan T. Patwardhan, Kaustubh Pons, Eduardo Erhart, Kevin Wake, Karsten Culberson, Wesley S. Hill, Patrick M. Smith, Blake R. affil: Roy J. Carver Department of Biomedical Engineering, University of Iowa, 5601 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA 52242, USA sug: subj: Proton Therapy Evaluation Dosimetry Treatment Duration Radiotherapy, Conformal Algorithms Patient Care Plans Human United States Food and Drug Administration Descriptive Statistics Dosage Calculation Funding Source Radiation Dosage Quality Assurance ab: Simple Summary: The Dynamic Collimation System (DCS) is a novel, pre-clinical per-spot energy-specific collimator for pencil beam scanning proton therapy that is designed to improve the amount of healthy tissue sparing achieved in low-energy proton therapy treatments. Improved sparing of healthy tissue is expected to improve treatment outcomes including quality of life for cancer survivors. From its infancy, the DCS has shown theoretical promise, and the culmination of several years of DCS development has transformed this technology from a conceptual idea into a pre-clinical prototype. This work focuses on the specific development, implementation, and testing of a novel treatment planning framework to enable clinically deliverable DCS treatments that are highly efficient and conformal. The results from this study provide some of the first clinical evidence of the healthy tissue sparing that is achievable from the DCS and represent a necessary step in the progression of this next-generation technology into clinical practice. Background and objectives: Previous dynamic collimator system (DCS) developments included: (1) hardware construction and commissioning, (2) an accurate dose calculation algorithm, (3) a quality assurance approach, and (4) development of optimization tools for treatment planning. Clinical DCS implementation necessitates efficient treatment plan delivery and fully integrated tools. In this work, a novel algorithm for minimizing treatment time was developed with the goal of reducing the DCS time increase, relative to conventional pencil beam scanning, to one minute or less per beam. In this extensive end-to-end evaluation, treatment plans generated with a modified U.S. Food and Drug Administration (FDA)-cleared treatment planning system were delivered on an Ion Beam Applications (IBA) Proteus Plus proton therapy system, with and without a DCS, to evaluate delivery times and dosimetric accuracy for a relatively large patient dataset, providing evidence of the clinical potential of the approach. Methods: Ten previously treated brain patients were replanned, consisting of both deep-seated central and superficial targets, the latter of which required an external 4 cm polyethylene range shifter. DCS treatments were optimized using a maximum conformity planning technique exploiting per-spot collimator capabilities. An optimization algorithm was incorporated to minimize treatment delivery time by determining the optimal sequencing of spot positions and collimator settings. Plan quality was quantified using conformity and dose-volume histogram (DVH)-based metrics while delivery accuracy was validated through measurements using both patient-specific quality assurance (PSQA) and log file analysis at the Miami Cancer Institute (MCI). Results: The DCS reduced the dose gradient index on average by 26.4% (17.7–37.1%) and the mean dose to the adjacent healthy tissue (within 10 mm of the target) by 19.3% (16.3–26.2%). The average reduction to the mean and maximum dose to the involved optic nerves was 50% (25.7–80.7%) and 18.7%, respectively, and the mean and D2cc dose to the involved brainstem was reduced by 63.9% (31.5–96.4%) and 60.4% (10.8–99.8%), respectively. PSQA pass rates among DCS-collimated and baseline uncollimated treatments were 99.7% and 99.2%, respectively. DCS treatment fields were delivered within an average of 49 s (32–61 s) from their uncollimated intensity modulated proton therapy (IMPT) counterparts. Average spot position errors were −0.05 ± 0.2 mm and 0.04 ± 0.2 mm for the x- and y-position, respectively. The maximum error in magnitude for collimator positioning was 0.2 mm or less. Conclusions: DCS collimated IMPT treatments can provide significant dosimetric improvements over uncollimated treatments. These highly collimated treatments can be delivered with sufficient accuracy for clinical use while incurring an additional time penalty of around one minute or less per field compared to uncollimated treatments. pubtype: Academic Journal doctype: diagnostic images equations & formulas pictorial research tables/charts Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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