Design and feasibility of a flexible, on-body, high impedance coil receive array for a 1.5 T MR-linac
| Autor: | Luca van Dijk, Cornelis A. T. van den Berg, J G M Kok, Rob H N Tijssen, S.L. Hackett, Victor N. Malkov, Jan J W Lagendijk, Stefan E Zijlema |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
receive array
Computer science low attenuation Acoustics medicine.medical_treatment Signal-To-Noise Ratio Radiation MR-linac Linear particle accelerator 030218 nuclear medicine & medical imaging law.invention 03 medical and health sciences High impedance Acceleration 0302 clinical medicine law high impedance coil Electric Impedance medicine Humans Radiology Nuclear Medicine and imaging Irradiation Electrical impedance Mechanical Phenomena Radiological and Ultrasound Technology Phantoms Imaging Equipment Design Magnetic Resonance Imaging Radiation therapy Capacitor Signal-to-noise ratio (imaging) Electromagnetic coil Radiology Nuclear Medicine and imaging 030220 oncology & carcinogenesis radiolucent MRI-guided radiotherapy Feasibility Studies Particle Accelerators Mri guided radiotherapy |
| Zdroj: | Physics in Medicine and Biology, 64(18). IOP Publishing Ltd. |
| ISSN: | 0031-9155 |
| Popis: | The lack of radiation-attenuating tuning capacitors in high impedance coils (HICs) make HICs an interesting building block of receive arrays for MRI-guided radiotherapy (MRIgRT). Additionally, their flexibility and limited channel coupling allow for low-density support materials, which are likely to be more radiation transparent (radiolucent). In this work, we introduce the use of HICs in receive arrays for MRIgRT treatments. We discuss the design and show the dosimetric feasibility of a HIC receive array that has a high channel count and aims to improve the imaging performance of the 1.5 T MR-linac. Our on-body design comprises an anterior and posterior element, which each feature a channel layout (32 channels total). The anterior element is flexible, while the posterior element is rigid to support the patient. Mockups consisting of support materials and conductors were built, irradiated, and optimized to minimize impact on the surface dose (7% of the dose maximum) and dose at depth ( 0.8% under a single conductor and 1.4% under a conductor crossing). Anatomical motion and the use of multiple beam angles will ensure that these slight dose changes at depth are clinically insignificant. Subsequently, several functional, single-channel HIC imaging prototypes and a 5-channel array were built to assess the performance in terms of signal-to-noise ratio (SNR). The performance was compared to the clinical MR-linac array and showed that the 5-channel imaging prototype outperformed the clinical array in terms of SNR and channel coupling. Imaging performance was not affected by the radiation beam. In conclusion, the use of HICs allowed for the design of our flexible, on-body receive array for MRIgRT. The design was shown to be dosimetrically feasible and improved the SNR. Future research with a full array will need to show the gain in parallel imaging performance and thus acceleration. |
| Databáze: | OpenAIRE |
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