Technical Note: Radiological properties of tissue surrogates used in a multimodality deformable pelvic phantom for MR‐guided radiotherapy

Niebuhr, Nina I.; Johnen, W.; Güldaglar, Timur; Runz, A.; Echner, G.; Mann, P.; Möhler, Christian; Pfaffenberger, A.; Jäkel, Oliver; Greilich, Steffen

doi:10.1118/1.4939874

Cited by 54 publications

(89 citation statements)

References 49 publications

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“…Figure demonstrates a brain phantom composed of compartments that are loaded with either radioactive and/or nonradioactive solutions. For example, agarose gel, water, K 2 HPO 4 , agar‐based mixture, olive oil, and vaseline are nonradioactive solutions, which represent brain gel, ventricle liquid, bone liquid, prostate tissue and adipose tissue, respectively . Other studies, such as Lai et al and Morais et al used nonradioactive solutions to mimic the blood flow, which is an important physiological parameter.…”

Section: Resultsmentioning

confidence: 99%

Recent advances on the development of phantoms using 3D printing for imaging with CT, MRI, PET, SPECT, and ultrasound

2018

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Purpose: Printing technology, capable of producing three-dimensional (3D) objects, has evolved in recent years and provides potential for developing reproducible and sophisticated physical phantoms. 3D printing technology can help rapidly develop relatively low cost phantoms with appropriate complexities, which are useful in imaging or dosimetry measurements. The need for more realistic phantoms is emerging since imaging systems are now capable of acquiring multimodal and multiparametric data. This review addresses three main questions about the 3D printers currently in use, and their produced materials. The first question investigates whether the resolution of 3D printers is sufficient for existing imaging technologies. The second question explores if the materials of 3D-printed phantoms can produce realistic images representing various tissues and organs as taken by different imaging modalities such as computer tomography (CT), positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), ultrasound (US), and mammography. The emergence of multimodal imaging increases the need for phantoms that can be scanned using different imaging modalities. The third question probes the feasibility and easiness of "printing" radioactive or nonradioactive solutions during the printing process. Methods: A systematic review of medical imaging studies published after January 2013 is performed using strict inclusion criteria. The databases used were Scopus and Web of Knowledge with specific search terms. In total, 139 papers were identified; however, only 50 were classified as relevant for this paper. In this review, following an appropriate introduction and literature research strategy, all 50 articles are presented in detail. A summary of tables and example figures of the most recent advances in 3D printing for the purposes of phantoms across different imaging modalities are provided. Results: All 50 studies printed and scanned phantoms in either CT, PET, SPECT, mammography, MRI, and US-or a combination of those modalities. According to the literature, different parameters were evaluated depending on the imaging modality used. Almost all papers evaluated more than two parameters, with the most common being Hounsfield units, density, attenuation and speed of sound. Conclusions: The development of this field is rapidly evolving and becoming more refined. There is potential to reach the ultimate goal of using 3D phantoms to get feedback on imaging scanners and reconstruction algorithms more regularly. Although the development of imaging phantoms is evident, there are still some limitations to address: One of which is printing accuracy, due to the printer properties. Another limitation is the materials available to print: There are not enough materials to mimic all the tissue properties. For example, one material can mimic one property-such as the density of real tissue-but not any other property, like speed of sound or attenuation.

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Section: Resultsmentioning

confidence: 99%

Recent advances on the development of phantoms using 3D printing for imaging with CT, MRI, PET, SPECT, and ultrasound

2018

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“…This phantom is not suitable for use as a magnetic resonance imaging (MRI) phantom since nylon and gypsum are not visible on MRI. MRI contrast agents such as gadolinium could be added during the printing process . Although no movement or deformation of internal structures is possible, movement of the whole phantom can be achieved by moving the radiotherapy treatment couch or by using a mobile platform.…”

Section: Discussionmentioning

confidence: 99%

Using 3D printing techniques to create an anthropomorphic thorax phantom for medical imaging purposes

et al. 2017

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Purpose: Imaging phantoms are widely used for testing and optimization of imaging devices without the need to expose humans to irradiation. However, commercially available phantoms are commonly manufactured in simple, generic forms and sizes and therefore do not resemble the clinical situation for many patients. Methods: Using 3D printing techniques, we created a life-size phantom based on a clinical CT scan of the thorax from a patient with lung cancer. It was assembled from bony structures printed in gypsum, lung structures consisting of airways, blood vessels >1 mm, and outer lung surface, three lung tumors printed in nylon, and soft tissues represented by silicone (poured into a 3D-printed mold). Results: Kilovoltage x-ray and CT images of the phantom closely resemble those of the real patient in terms of size, shapes, and structures. Surface comparison using 3D models obtained from the phantom and the 3D models used for printing showed mean differences <1 mm for all structures. Tensile tests of the materials used for the phantom show that the phantom is able to endure radiation doses over 24,000 Gy. Conclusions: It is feasible to create an anthropomorphic thorax phantom using 3D printing and molding techniques. The phantom closely resembles a real patient in terms of spatial accuracy and is currently being used to evaluate x-ray-based imaging quality and positional verification techniques for radiotherapy.

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“…Previously reported MR/CT-visible materials in the literature did not meet IROC-Houston's criteria since most of these materials shared short shelf lives and required refrigeration storage. [14][15][16] We tested over 80 materials, which could potentially be used to manufacture IROC-Houston's MRgRT TABLE III. A measured film PDD curve and a TPS PDD curve were generated for both current IROC-Houston's phantom materials and testing materials for a large (10 9 10 cm 2 ), medium (6 9 6 cm 2 ), and small (3 9 3 cm 2 ) field size.…”

Section: Discussionmentioning

confidence: 99%

“…Other researchers have attempted to create dual MR/CT phantoms, but the phantoms are limited by either: shelf-life storage, require refrigeration or additives to prevent microorganism growth and therefore were not suitable for shipping to other RT institutions. [14][15][16] The aim of this study was to identify and characterize synthetic tissue equivalent (STE) materials that could be used to develop an anthropomorphic dual MR/CT QA phantom which would require minimal maintenance, and be used to credential RT institutions wishing to use MRgRT modalities in NCI-funded clinical trials.…”

Section: Introductionmentioning

confidence: 99%

Developing and characterizing MR/CT‐visible materials used in QA phantoms for MRgRT systems

et al. 2017

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Technical Note: Radiological properties of tissue surrogates used in a multimodality deformable pelvic phantom for MR‐guided radiotherapy

Abstract: The presented surrogates and techniques allow the customized construction of multimodality, anthropomorphic, and deformable phantoms as exemplarily shown for a pelvic phantom, which is intended to study adaptive treatment scenarios in MR-guided radiation therapy.

Cited by 54 publications

References 49 publications

Recent advances on the development of phantoms using 3D printing for imaging with CT, MRI, PET, SPECT, and ultrasound

Recent advances on the development of phantoms using 3D printing for imaging with CT, MRI, PET, SPECT, and ultrasound

Using 3D printing techniques to create an anthropomorphic thorax phantom for medical imaging purposes

Developing and characterizing MR/CT‐visible materials used in QA phantoms for MRgRT systems

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