Small animal IMRT using 3D printed compensators.

Published on Dec 26, 2020in International Journal of Radiation Oncology Biology Physics5.859
· DOI :10.1016/J.IJROBP.2020.12.028
Gage Redler10
Estimated H-index: 10
,
E Pearson6
Estimated H-index: 6
(U of C: University of Chicago)
+ 7 AuthorsRodney D. Wiersma1
Estimated H-index: 1
(UPenn: University of Pennsylvania)
Sources
Abstract
PURPOSE Preclinical radiation replicating clinical IMRT techniques can provide data translatable to clinical practice. For this work, treatment plans are created for oxygen-guided dose-painting in small animals utilizing inverse-planned IMRT. Spatially varying beam intensities were achieved using 3D-printed compensators. METHODS AND MATERIALS Optimized beam fluence from arbitrary gantry angles was determined using a verified model of the XRAD225Cx treatment beam. Compensators were 3D-printed with varied thickness to provide desired attenuation using copper/polylactic-acid(CuPLA). Spatial resolution capabilities were investigated using printed test-patterns. Following AAPM TG119, a 5-beam IMRT plan was created for a miniaturized(∼1/8th scale) C-shape target. Electron paramagnetic resonance imaging of murine tumor oxygenation guided simultaneous integrated boost (SIB) plans conformally treating tumor to a base dose(Rx1) with boost(Rx2) based on tumor oxygenation. The 3D printed compensator intensity modulation accuracy/precision was evaluated by individually delivering each field to a phantom containing radiochromic film and subsequent per-field gamma analysis. The methodology was validated end-to-end with composite delivery (incorporating 3D printed tungsten/polylactic-acid(WPLA) beam trimmers to reduce out-of-field leakage) of the oxygen-guided SIB plan to a phantom containing film and subsequent gamma analysis. RESULTS Resolution test-patterns demonstrate practical printer resolution of ∼0.7mm, corresponding to 1.0mm bixels at isocenter. The miniaturized C-shape plan provides PTV coverage (V95%=95%) with organ sparing (OAR Dmax<50%). SIB plan to hypoxic tumor demonstrates utility of this approach (hypoxic tumor V95%,Rx2=91.6%, normoxic tumor V95%,Rx1=95.7%, normal tissue V100%,Rx1=7.1%). The more challenging SIB plan to boost normoxic tumor rim achieved normoxic tumor V95%,Rx2=90.9%, hypoxic tumor V95%,Rx1=62.7%, normal tissue V100%,Rx2=5.3%. Average per-field gamma passing rates using 3%/1.0mm, 3%/0.7mm, and 3%/0.5mm criteria were 98.8±2.8%, 96.6±4.1%, and 90.6±5.9%, respectively. Composite delivery of the hypoxia boost plan and gamma analysis (3%/1mm) gave passing results of 95.3% and 98.1% for two measured orthogonal dose planes. CONCLUSIONS This simple/cost-effective approach using 3D-printed compensators for small-animal IMRT provides a methodology enabling preclinical studies readily translatable into the clinic. The presented oxygen-guided dose-painting demonstrates that this methodology will facilitate studies driving much needed biologic personalization of radiotherapy for improvements in patient outcomes.
References54
Newest
#1Suk W. Yoon (UPenn: University of Pennsylvania)H-Index: 4
#2Jacob Kodra (Duke University)H-Index: 2
Last. Mark Oldham (Duke University)H-Index: 43
view all 5 authors...
PURPOSE: The purpose of this study was to investigate the feasibility of using fused deposition modeling (FDM) 3D-printer to generate radiation compensators for high-resolution (~1mm) intensity modulated radiation therapy (IMRT) for small animal radiation treatment. We propose a novel method incorporating 3D printed compensator molds filled with NaI powder. METHODS: The inverse planning module of the Computational Environment for Radiotherapy Research (CERR) software was adapted to simulate the ...
1 CitationsSource
#1K. Woods (UCLA: University of California, Los Angeles)H-Index: 8
#2Ryan Neph (UCLA: University of California, Los Angeles)H-Index: 5
Last. Ke Sheng (UCLA: University of California, Los Angeles)H-Index: 31
view all 4 authors...
PURPOSE: A dose-modulation device for small animal radiotherapy is required to use clinically analogous treatment techniques, which will likely increase the translatability of preclinical research results. Because the clinically used multileaf collimator (MLC) is impractical for miniaturization, we have developed a simpler, better-suited sparse orthogonal collimator (SOC) for delivering small animal intensity-modulated radiation therapy (IMRT) using a rectangular aperture optimization (RAO) trea...
2 CitationsSource
#1K. Woods (UCLA: University of California, Los Angeles)H-Index: 8
#2Dan Nguyen (UCLA: University of California, Los Angeles)H-Index: 23
Last. Ke Sheng (UCLA: University of California, Los Angeles)H-Index: 31
view all 6 authors...
PURPOSE: To achieve more translatable preclinical research results, small animal irradiation needs to more closely simulate human radiotherapy. Although the clinical gold standard is intensity-modulated radiation therapy (IMRT), the direct translation of this method for small animals is impractical. In this study we describe the treatment planning system for a novel dose modulation device to address this challenge. METHODS: Using delineated target and avoidance structures, a rectangular aperture...
2 CitationsSource
#1Michal Gonet (Jagiellonian University)H-Index: 3
#2Boris Epel (U of C: University of Chicago)H-Index: 27
Last. Martyna Elas (Jagiellonian University)H-Index: 18
view all 4 authors...
This paper presents a survey of electron paramagnetic resonance (EPR) image registration. Image registration is the process of overlaying images (two or more) of the same scene taken at different times, from different viewpoints and/or different techniques. EPR-imaging (EPRI) techniques belong to the functional-imaging modalities and therefore suffer from a lack of anatomical reference which is mandatory in preclinical imaging. For this reason, it is necessary to merging EPR images with other mo...
3 CitationsSource
#1Boris Epel (U of C: University of Chicago)H-Index: 27
#2Matthew C. Maggio (U of C: University of Chicago)H-Index: 3
Last. Howard J. Halpern (U of C: University of Chicago)H-Index: 40
view all 11 authors...
Purpose It has been known for over 100 years that tumor hypoxia, a near-universal characteristic of solid tumors, decreases the curative effectiveness of radiation therapy. However, to date, there are no reports that demonstrate an improvement in radiation effectiveness in a mammalian tumor on the basis of tumor hypoxia localization and local hypoxia treatment. Methods and Materials For radiation targeting of hypoxic subregions in mouse fibrosarcoma, we used oxygen images obtained using pulse el...
22 CitationsSource
#1Stefan J van Hoof (UM: Maastricht University)H-Index: 10
#2Joana B Verde (UM: Maastricht University)H-Index: 1
Last. Frank Verhaegen (UM: Maastricht University)H-Index: 59
view all 3 authors...
Objective:Using synchronized three-dimensional stage translation and multiangle radiation delivery to improve conformality and homogeneity of radiation delivery to complexly shaped target volumes f...
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#1David Parsons (UTSW: University of Texas Southwestern Medical Center)H-Index: 6
#2Cody Church (Dal: Dalhousie University)H-Index: 2
Last. Alasdair Syme (Dal: Dalhousie University)H-Index: 8
view all 3 authors...
Abstract Purpose Pre-clinical irradiation systems use kilovoltage x-ray systems to deliver small fields of radiation in static beam arrangements or arcs. The systems are costly and the radiobiological effectiveness of kilovoltage beams is known to differ from the megavoltage photon beams used clinically. This work used Developer mode on the Varian TrueBeam STx linear accelerator to create a pre-clinical irradiator capable of treating millimeter-sized targets. Materials and methods A treatment fi...
1 CitationsSource
#1Wilfred Ngwa (Brigham and Women's Hospital)H-Index: 19
#2Omoruyi Credit Irabor (Brigham and Women's Hospital)H-Index: 3
Last. Silvia C. Formenti (Cornell University)H-Index: 79
view all 6 authors...
The abscopal effect, which is the regression of metastatic cancer at distant sites during radiotherapy, is somewhat rare but can be promoted by immunotherapy. This Opinion article describes emerging concepts and limitations of using a combination of radiotherapy and immunotherapy to boost the abscopal effect.
321 CitationsSource
: Oxygen deprivation (hypoxia) in non-small cell lung cancer (NSCLC) is an important factor in treatment resistance and poor survival. Hypoxia is an attractive therapeutic target, particularly in the context of radiotherapy, which is delivered to more than half of NSCLC patients. However, NSCLC hypoxia-targeted therapy trials have not yet translated into patient benefit. Recently, early termination of promising evofosfamide and tarloxotinib bromide studies due to futility highlighted the need fo...
88 CitationsSource
#1Frank Verhaegen (Maastricht University Medical Centre)H-Index: 59
#2Ludwig Dubois (Maastricht University Medical Centre)H-Index: 37
Last. Dietmar Georg (Medical University of Vienna)H-Index: 59
view all 14 authors...
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