The development of this field is rapidly evolving and becoming more refined. Almost all papers evaluated more than two parameters, with the most common being Hounsfield units, density, attenuation and speed of sound. According to the literature, different parameters were evaluated depending on the imaging modality used. 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.Īll 50 studies printed and scanned phantoms in either CT, PET, SPECT, mammography, MRI, and US - or a combination of those modalities. In this review, following an appropriate introduction and literature research strategy, all 50 articles are presented in detail. In total, 139 papers were identified, however only 50 were classified as relevant for the purpose of this paper.
The databases used were Scopus and Web of Knowledge with specific search terms. The third question probes the feasibility and easiness of "printing" radioactive and/or non-radioactive solutions during the printing process.Ī systematic review of medical imaging studies published after January 2013 is performed using strict inclusion criteria. The emergence of multimodal imaging increases the need for phantoms that can be scanned using different imaging modalities. 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 first question investigates whether the resolution of 3D printers is sufficient for existing imaging technologies. This review addresses three main questions about the 3D printers currently in use, and their produced materials. The need for more realistic phantoms is emerging since imaging systems are now capable of acquiring multimodal and multiparametric data. 3D printing technology can help rapidly develop relatively low cost phantoms with appropriate complexities, which are useful in imaging or dosimetry measurements. Printing technology, capable of producing three-dimensional (3D) objects, has evolved in recent years and provides potential for developing reproducible and sophisticated physical phantoms. Preliminary data suggests that several radiotracers might be feasible to estimate the BF in major oxygen-dependent organs. In the human study cohort, the renal BFs from the two performed imaging modalities showed a good correlation (r = 0.61, p = 0.001) and a small significant difference (p = 0.047) among each other and good correlations to the reference value obtained from blood sampling (r = 0.79 and r = 0.52).Ī mathematical approach was developed to assess the organ BF solely from dynamic imaging scans without the necessity of additional measurements.
The mean organ-specific BF determined in the mouse model revealed no significant differences between the administered radiotracers and all calculated values corresponded to normal values (kidneys: 1.0-1.1 ml/min, liver: 1.4–1.6 ml/min, brain: 0.2 ml/min). The approach was also applied on renal scans with two different imaging modalities from a representative cohort of 32 human subjects and compared to reference values. Independence of tracer characteristics was evaluated with major oxygen-dependent organs (kidneys, liver, brain) of a mouse model.
The new approach uses the early phase of time activity curves extracted from animal and human dynamic scintigraphy and PET scans. The aim of this study was to investigate a new mathematical approach developed to estimate the organ BF from dynamic imaging data and to analyze if this method can be applied independent of the used radio tracer or imaging modality. Its assessment in the course of routine nuclear medicine examinations, including planar scintigraphy and positron emission tomography (PET), can be relevant for the diagnosis and monitoring of various conditions. The blood flow (BF) is a critical determinant of organ functionality.
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