Methodologies and tools for proton beam design for lung tumors

Moyers, Michael F.; Miller, Daniel W.; Bush, David A.; Slater, Jerry D.

doi:10.1016/s0360-3016(00)01555-8

Cited by 238 publications

(206 citation statements)

References 10 publications

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“…Urie et al (1) proposed a correction strategy for the double scattering (DS) technique by minimizing compensator thickness over a smeared radius (i.e., the misaligned distance of the target), and extending the distal and proximal proton beam range by a percentage given by the uncertainty in converting CT Hounsfield units to stopping power. This "smearing" approach uses a perpendicular search radius, typically fixed at 5 mm, over the entire beam path to add treatment margin to the target along the beam path and was implemented in the treatment of thoracic tumors by Moyers et al (2) using the DS technique. In contrast to the implicit smearing embedded in the compensator design and direct manipulation of the distal and proximal ranges of DS beams, Park et al (3) introduced a beam‐specific PTV (BSPTV), initially proposed by Rietzel and Bert, (4) to explicitly include variation of water‐equivalent path length (WEPL) along each beam direction; in this manner the BSPTV can be used in pencil beam scanning (PBS) planning single field optimization (SFO).…”

Section: Introductionmentioning

confidence: 99%

Beam‐specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors

Lin

Kang

Huang

et al. 2015

J Applied Clin Med Phys

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The purpose of this study is to determine whether organ sparing and target coverage can be simultaneously maintained for pencil beam scanning (PBS) proton therapy treatment of thoracic tumors in the presence of motion, stopping power uncertainties, and patient setup variations. Ten consecutive patients that were previously treated with proton therapy to 66.6/1.8 Gy (RBE) using double scattering (DS) were replanned with PBS. Minimum and maximum intensity images from 4D CT were used to introduce flexible smearing in the determination of the beam specific PTV (BSPTV). Datasets from eight 4D CT phases, using ±3% uncertainty in stopping power and ±3 mm uncertainty in patient setup in each direction, were used to create 8×12×10=960 PBS plans for the evaluation of 10 patients. Plans were normalized to provide identical coverage between DS and PBS. The average lung V20, V5, and mean doses were reduced from 29.0%, 35.0%, and 16.4 Gy with DS to 24.6%, 30.6%, and 14.1 Gy with PBS, respectively. The average heart V30 and V45 were reduced from 10.4% and 7.5% in DS to 8.1% and 5.4% for PBS, respectively. Furthermore, the maximum spinal cord, esophagus, and heart doses were decreased from 37.1 Gy, 71.7 Gy, and 69.2 Gy with DS to 31.3 Gy, 67.9 Gy, and 64.6 Gy with PBS. The conformity index (CI), homogeneity index (HI), and global maximal dose were improved from 3.2, 0.08, 77.4 Gy with DS to 2.8, 0.04, and 72.1 Gy with PBS. All differences are statistically significant, with p‐values <0.05, with the exception of the heart V45 (p=0.146). PBS with BSPTV achieves better organ sparing and improves target coverage using a repainting method for the treatment of thoracic tumors. Incorporating motion‐related uncertainties is essential.PACS number: 87.55.D

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Section: Introductionmentioning

confidence: 99%

Beam‐specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors

Lin

Kang

Huang

et al. 2015

J Applied Clin Med Phys

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“…In order to quantitatively assess the effect of both variables on proton dose distributions, the use of a combined dose and range criteria is necessary. Differences in HU values for the same phantom using two different CT scanners are known to cause a range uncertainty in the 1%–3% range 11, 12. Dose, range, and stopping power are strongly correlated in proton beams.…”

Section: Discussionmentioning

confidence: 99%

“…The mean CT value of each plug for a particular CT scanner and scan technique is then correlated with that stopping power. The accuracy of the chemical composition, the stopping powers, of each of those elements, and also the noise in the CT value will affect the accuracy of the stopping power 11, 12. The uncertainties in the stopping power as it relates to the CT values can lead to uncertainties in the calculated range.…”

Section: Introductionmentioning

confidence: 99%

Commissioning an in‐room mobile CT for adaptive proton therapy with a compact proton system

Oliver

Zeidan

Meeks

et al. 2018

J Applied Clin Med Phys

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PurposeTo describe the commissioning of AIRO mobile CT system (AIRO) for adaptive proton therapy on a compact double scattering proton therapy system.MethodsA Gammex phantom was scanned with varying plug patterns, table heights, and mAs on a CT simulator (CT Sim) and on the AIRO. AIRO‐specific CT‐stopping power ratio (SPR) curves were created with a commonly used stoichiometric method using the Gammex phantom. A RANDO anthropomorphic thorax, pelvis, and head phantom, and a CIRS thorax and head phantom were scanned on the CT Sim and AIRO. Clinically realistic treatment plans and nonclinical plans were generated on the CT Sim images and subsequently copied onto the AIRO CT scans for dose recalculation and comparison for various AIRO SPR curves. Gamma analysis was used to evaluate dosimetric deviation between both plans.Results AIRO CT values skewed toward solid water when plugs were scanned surrounded by other plugs in phantom. Low‐density materials demonstrated largest differences. Dose calculated on AIRO CT scans with stoichiometric‐based SPR curves produced over‐ranged proton beams when large volumes of low‐density material were in the path of the beam. To create equivalent dose distributions on both data sets, the AIRO SPR curve's low‐density data points were iteratively adjusted to yield better proton beam range agreement based on isodose lines. Comparison of the stoichiometric‐based AIRO SPR curve and the “dose‐adjusted” SPR curve showed slight improvement on gamma analysis between the treatment plan and the AIRO plan for single‐field plans at the 1%, 1 mm level, but did not affect clinical plans indicating that HU number differences between the CT Sim and AIRO did not affect dose calculations for robust clinical beam arrangements.ConclusionBased on this study, we believe the AIRO can be used offline for adaptive proton therapy on a compact double scattering proton therapy system.

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“…Two proton beam energy levels, 150 and 210 MeV, were determined with the depths of distal and proximal edges of a target. Distal, proximal, and smearing margins were fundamentally calculated using Strategy 2 as reported previously (Moyers et al 2001). Treatment parameters were adjusted according to PTV coverage and organ-at-risk position.…”

Section: Treatment Planningmentioning

confidence: 99%

Dosemetric Parameters Predictive of Rib Fractures after Proton Beam Therapy for Early-Stage Lung Cancer

Ishikawa

Nakamura

Katō

et al. 2016

Tohoku J. Exp. Med.

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Proton beam therapy (PBT) is the preferred modality for early-stage lung cancer. Compared with X-ray therapy, PBT offers good dose concentration as revealed by the characteristics of the Bragg peak. Rib fractures (RFs) after PBT lead to decreased quality of life for patients. However, the incidence of and the risk factors for RFs after PBT have not yet been clarified. We therefore explored the relationship between irradiated rib volume and RFs after PBT for early-stage lung cancer. The purpose of this study was to investigate the incidence and the risk factors for RFs following PBT for early-stage lung cancer. We investigated 52 early-stage lung cancer patients and analyzed a total of 215 irradiated ribs after PBT. Grade 2 RFs occurred in 12 patients (20 ribs); these RFs were symptomatic without displacement. No patient experienced more severe RFs. The median time to grade 2 RFs development was 17 months (range: 9-29 months). The three-year incidence of grade 2 RFs was 30.2%. According to the analysis comparing radiation dose and rib volume using receiver operating characteristic curves, we demonstrated that the volume of ribs receiving more than 120 Gy 3 (relative biological effectiveness (RBE)) was more than 3.7 cm 3 at an area under the curve of 0.81, which increased the incidence of RFs after PBT (P < 0.001). In this study, RFs were frequently observed following PBT for early-stage lung cancer. We demonstrated that the volume of ribs receiving more than 120 Gy 3 (RBE) was the most significant parameter for predicting RFs.

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Methodologies and tools for proton beam design for lung tumors

Cited by 238 publications

References 10 publications

Beam‐specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors

Beam‐specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors

Commissioning an in‐room mobile CT for adaptive proton therapy with a compact proton system

Dosemetric Parameters Predictive of Rib Fractures after Proton Beam Therapy for Early-Stage Lung Cancer

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