A Method for Manufacturing Oncological Phantoms for the Quantification of 18F-FDG PET and DW-MRI Studies

Abstract

The aim of this work was to develop a method to manufacture oncological phantoms for quantitation purposes in 18F-FDG PET and DW-MRI studies. Radioactive and diffusion materials were prepared using a mixture of agarose and sucrose radioactive gels. T2 relaxation and diffusion properties of gels at different sucrose concentrations were evaluated. Realistic oncological lesions were created using 3D-printed plastic molds filled with the gel mixture. Once solidified, gels were extracted from molds and immersed in a low-radioactivity gel simulating normal background tissue. A breast cancer phantom was manufactured using the proposed method as an exploratory feasibility study, including several realistic oncological configurations in terms of both radioactivity and diffusion. The phantom was acquired in PET with 18F-FDG, immediately after solidification, and in DW-MRI the following day. Functional volumes characterizing the simulated BC lesions were segmented from PET and DW-MRI images. Measured radioactive uptake and ADC values were compared with gold standards. Phantom preparation was straightforward, and the time schedule was compatible with both PET and MRI measurements. Lesions appeared on 18F-FDG PET and DW-MRI images as expected, without visible artifacts. Lesion functional parameters revealed the phantom's potential for validating quantification methods, in particular for new generation hybrid PET-MRI systems.

DW‑MRI for esophageal squamous cell carcinoma, correlations between ADC values with histologic differentiation and VEGF expression: A retrospective study

“…Clinically, enhancement computed tomography (CT), contrast enhanced magnetic resonance imaging (MRI) and barium meal is the main methods for evaluating the lesion and therapeutic effects (3). However, these examinations are judged by anatomical morphological changes, and lack the ability to display the microscopic pathology and physiological status of the tumor (4).…”

A tri-modal tissue-equivalent anthropomorphic phantom for PET, CT and multi-parametric MRI radiomics

“…Sucrose concentration (10%, 20%, 30% and 40% w/v) was varied to manipulate both T1-weighted and diffusion contrasts [7].…”

“…In such a way, it is possible the direct translation of the phantom results to the analysis of cancer patients. The phantom was developed to simulate realistic oncological lesions, using molds printed on the basis of real oncological lesions [7,8] and can be customized for texture analysis with heterogeneous lesions, as previously reported in Gallivanone F et al (2018) [8].…”

Multimodal phantoms for clinical PET/MRI

“…Agarose, gelatin and methyl-cellulose gels are used more widely as soft tissue surrogates in several phantoms identified for this review [ 13 , 14 , 20 – 23 ]. The ability to customise the MRI relaxation properties of gels with relative ease at manufacture by varying the concentration of gelling and contrast agents, demonstrated extensively by Gillmann et al [ 21 ], allows for flexibility in the number of tissue types represented.…”

“…Gels can be used to fill cavities or moulded to hold structure without a casing, both of which provided a reproducible geometry. Moulded structures such as tumours or lesions may then be placed inside a larger gel tissue surrogate [ 23 ]. In phantoms simulating cardiac and respiratory motion [ 20 , 24 – 26 ], gels offer an alternative to water whilst maintaining the flexibility to allow movement to occur.…”