Anthropomorphic thorax phantom for cardio-respiratory motion simulation in tomographic imaging

Abstract

Patient motion during medical imaging using techniques such as computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), or single emission computed tomography (SPECT) is well known to degrade images, leading to blurring effects or severe artifacts. Motion correction methods try to overcome these degrading effects. However, they need to be validated under realistic conditions. In this work, a sophisticated anthropomorphic thorax phantom is presented that combines several aspects of a simulator for cardio-respiratory motion. The phantom allows us to simulate various types of cardio-respiratory motions inside a human-like thorax, including features such as inflatable lungs, beating left ventricular myocardium, respiration-induced motion of the left ventricle, moving lung lesions, and moving coronary artery plaques. The phantom is constructed to be MR-compatible. This means that we can not only perform studies in PET, SPECT and CT, but also inside an MRI system. The technical features of the anthropomorphic thorax phantom Wilhelm are presented with regard to simulating motion effects in hybrid emission tomography and radiotherapy. This is supplemented by a study on the detectability of small coronary plaque lesions in PET/CT under the influence of cardio-respiratory motion, and a study on the accuracy of left ventricular blood volumes.

Data‐driven gating in PET: Influence of respiratory signal noise on motion resolution

“…Finally, an in‐house developed PET/MRI‐compatible anthropomorphic thorax phantom was scanned in the PET/MRI scanner . It comprised realistic inflatable lungs, a diaphragm‐like membrane, a heart insert, and small movable tubes simulating PET‐active lesions.…”

“…Finally, an in-house developed PET/MRI-compatible anthropomorphic thorax phantom was scanned in the PET/ MRI scanner. 24 It comprised realistic inflatable lungs, a diaphragm-like membrane, a heart insert, and small movable tubes simulating PET-active lesions. For this study, [ 18 F]FDG solution was filled into the background (7 kBq/mL at scan start), the heart (33 kBq/mL), and a lesion located at the diaphragm (180 kBq/mL, volume: 0.3 mL).…”

Cardiorespiratory motion‐tracking via self‐refocused rosette navigators

“…Evaluation of respiratory and cardiac motion extraction was performed with an MR‐compatible, anthropomorphic motion phantom . The phantom (see Figure ) is a life‐sized human torso model with a plastic thorax, inflatable silicone lungs, a deformable left ventricle model (LVM), and a liver compartment.…”

“…Evaluation of respiratory and cardiac motion extraction was performed with an MR-compatible, anthropomorphic motion phantom. 2 The phantom (see Figure 2) is a life-sized human torso model with a plastic thorax, inflatable silicone lungs, a deformable left ventricle model (LVM), and a liver compartment. Respiration is simulated by driving the diaphragm with a pneumatic piston, while cardiac motion is achieved by inflating the inner cavity of the LVM with water.…”

“…In the first part of this manuscript, we validate the proposed navigation method and automatic motion parameter extraction with a dynamic thorax phantom that provides realistic and controllable cardiorespiratory motion. Subsequently, the technique is applied to several human patient scans in order to demonstrate robustness and clinical feasibility.…”