Preclinical multimodality phantom design for quality assurance of tumor size measurement

Abstract

BackgroundEvaluation of changes in tumor size from images acquired by ultrasound (US), computed tomography (CT) or magnetic resonance imaging (MRI) is a common measure of cancer chemotherapy efficacy. Tumor size measurement based on either the World Health Organization (WHO) criteria or the Response Evaluation Criteria in Solid Tumors (RECIST) is the only imaging biomarker for anti-cancer drug testing presently approved by the United States Food and Drug Administration (FDA). The aim of this paper was to design and test a quality assurance phantom with the capability of monitoring tumor size changes with multiple preclinical imaging scanners (US, CT and MRI) in order to facilitate preclinical anti-cancer drug testing.MethodsThree phantoms (Gammex/UTHSCSA Mark 1, Gammex/UTHSCSA Mark 2 and UTHSCSA multimodality tumor measurement phantom) containing tumor-simulating test objects were designed and constructed. All three phantoms were scanned in US, CT and MRI devices. The size of test objects in the phantoms was measured from the US, CT and MRI images. RECIST, WHO and volume analyses were performed.ResultsThe smaller phantom size, simplified design and better test object CT contrast of the UTHSCSA multimodality tumor measurement phantom allowed scanning of the phantom in preclinical US, CT and MRI scanners compared with only limited preclinical scanning capability of Mark 1 and Mark 2 phantoms. For all imaging modalities, RECIST and WHO errors were reduced for UTHSCSA multimodality tumor measurement phantom (≤1.69 ± 0.33%) compared with both Mark 1 (≤ -7.56 ± 6.52%) and Mark 2 (≤ 5.66 ± 1.41%) phantoms. For the UTHSCSA multimodality tumor measurement phantom, measured tumor volumes were highly correlated with NIST traceable design volumes for US (R2 = 1.000, p < 0.0001), CT (R2 = 0.9999, p < 0.0001) and MRI (R2 = 0.9998, p < 0.0001).ConclusionsThe UTHSCSA multimodality tumor measurement phantom described in this study can potentially be a useful quality assurance tool for verifying radiologic assessment of tumor size change during preclinical anti-cancer therapy testing with multiple imaging modalities.

Sensitivity and accuracy of volumetry of pulmonary nodules on low-dose 16- and 64-row multi-detector CT: an anthropomorphic phantom study

“…This anthropomorphic phantom was also used for an image database of nodules of diameter larger than 5 mm of several shapes, but results for nodule detectability and comparing between manual and semi-automated measurements were not reported [12]. In some nodule detectability studies, solid nodules with a diameter of 2 to 3 mm were detected in all cases [8, 13, 14]. In these studies, the nodules were placed in known order and examined in a thoracic phantom without lung vessels.…”

Recommendations towards standards for quantitative MRI (qMRI) and outstanding needs

“…None of those prototypes have been broadly adopted outside the individual laboratories involved in the design. Nevertheless, these individual efforts show the existing demand for and tendency towards designing and implementing anatomical and tissue‐specific multimodal, multiparametric, preclinical qMRI phantoms . One suggestion from the workshop was to create an open‐source design of a reference object for preclinical imaging, such that a site could make a reliable reference object particular to their magnetic field strength and bore and coil sizes.…”

“…Nevertheless, these individual efforts show the existing demand for and tendency towards designing and implementing anatomical and tissuespecific multimodal, multiparametric, preclinical qMRI phantoms. 90,91 One suggestion from the workshop was to create an open-source design of a reference object for preclinical imaging, such that a site could make a reliable reference object particular to their magnetic field strength and bore and coil sizes. The availability of such phantoms would facilitate the promise of translation to human imaging studies.…”

Multicenter Evaluation of Geometric Accuracy of MRI Protocols Used in Experimental Stroke

“…Recently, other larger and more complex phantom designs have been proposed for monitoring geometric accuracy or performing 3D geometric distortion correction in preclinical MRI [18, 29–31], but their size inhibits their use with various imaging coils, they generally have lower construction precision and are currently not as cost-effective; as such, they were not used in this multicenter study. LEGO bricks were also used successfully for the development of clinical phantoms before [25].…”