Impact of immobilization base plates composed of various materials on the imaging quality of MR simulation during radiotherapy
Hu Qiaoqiao,Liu Zhuolun,Zhang Jian,Li Sha,Yue Haizhen,Wang Meijiao,Li Tian,Jin Sunjun,Zhang Yibao
Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing),Department of Radiation Oncology,Peking University Cancer Hospital& Institute,Beijing 100142,China (Hu QQ,Liu ZL,Zhang J,Li S,Yue HZ,Wang MJ,Li T,Zhang YB);National Institute of Metrology,Beijing 100029,China (Jin SJ)
Abstract： Objective To compare the impact of immobilization base plates composed of 7 types of materials on the MR-simulation imaging quality used for radiotherapy, aiming to provide reference data for clinical applications. Methods Using identical T1 and T2 sequences of Siemens MR-simulator, the MR images of ACR Large Phantom were acquired on the Orfit carbon fiber laminate,polycarbonate (PC),high precision base plate (HP),Jinan Huayuxin BR,WR,KP and SP materials, respectively. The imaging quality without any plate was used as the baseline data. The following metrics were compared:1.High-contrast spatial resolution:the sharpness of 3 pairs of hole arrays was observed, which represented resolutions of 1.1 mm,1.0 mm and 0.9 mm on the LR and AP directions;2.Image intensity uniformity in terms of percent integral uniformity (PIU):PIU=100×[1-((high-low)/(high+low)];3. Low-contrast resolution:distinguishable spokes representing resolutions of 5.1%, 3.6%, 2.5% and 1.4% were recorded. According to ACR recommendations, high-contrast resolution of 1.0 mm, PIU of T1WI and T2>82%and low-contrast spoke difference<3 were considered as clinically acceptable. Results High-contrast T1WI and T2WI resolutions of no plate, PC plate, HP plate and KP material were all 0.9 mm, and those of the remaining materials were worse than 0.9 mm. The T1WI and T2WI PIU of no plate was>87%, and the PIU of carbon fiber plate was reduced by> 25%. The PIU decrease of remaining materials was within ±4%. Except the carbon fiber plate, the low-contrast spokes of the remaining materials were within ±3 compared with the reference. Conclusions In clinical settings, carbon fiber plate exerts the most significant effect upon the MR-simulation imaging quality, which is unsuitable for MR simulation. Imaging quality of PC and HP plates are consistent with that of no plate. BR and KP materials exert slight effect upon MR signal. The remaining materials are of potential values for the manufacture of immobilization devices and accessories.
Hu Qiaoqiao,Liu Zhuolun,Zhang Jian et al. Impact of immobilization base plates composed of various materials on the imaging quality of MR simulation during radiotherapy[J]. Chinese Journal of Radiation Oncology, 2018, 27(4): 410-415.
[1] Aird EGA,Conway J.CT simulation for radiotherapy treatment planning[J].Br J Radiol,2002,75(900):937-949.DOI:10.1259/bjr.75.900.750937. [2] Rizzo S,Buscarino V,Origgi D,et al. Evaluation of diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) as early response biomarkers in cervical cancer patients[J].Radiol Med,2016,121(11):838-846.DOI:10.1007/s11547-016-0665-y. [3] Rasmussen JH,Nrgaard M,Hansen AE,et al. Feasibility of multiparametric imaging with PET/MR in head and neck squamous cell carcinoma[J].J Nucl Med,2017,58(1):69-74.DOI:10.2967/jnumed.116.180091. [4] Metcalfe P,Liney GP,Holloway L,et al. The potential for an enhanced role for MR in radiation-therapy treatment planning[J].Technol Cancer Res Treat,2013,12(5):429-446.DOI:10.7785/tcrt.2012.500342. [5] O′neill BDP,Salerno G,Thomas K,et al. MR vs. CT imaging:low rectal cancer tumour delineation for three-dimensional conformal radiotherapy[J].Br J Radiol,2009,82(978):509-513.DOI:10.1259/bjr/60198873. [6] Yu Y,Lee DH,Peng SL,et al. Assessment of glioma response to radiotherapy using multiple MRI biomarkers with manual and semiautomated segmentation algorithms[J].J Neuroimaging,2016,26(6):626-634.DOI:10.1111/jon.12354. [7] Sabater S,Pastor-Juan MDR,Berenguer R,et al. Analysing the integration of MR images acquired in a non-radiotherapy treatment position into the radiotherapy workflow using deformable and rigid registration[J].Radiother Oncol,2016,119(1):179-184.DOI:10.1016/j.radonc.2016.02.032. [8] 刘国才,胡泽田,朱苏雨,等.头颈部肿瘤PET与MRI融合放疗靶区自适应区域生长勾画[J].中国医学物理学杂志,2016,33(3):222-230.DOI:10.3969/j.issn.1005-202X.2016.03.002. Liu GC,Hu ZT,Zhu SY,et al. Adaptive region growing method for segmenting target volumes of head and neck cancers based on PET combined with MRI[J].Chin J Med Phys,2016,33(3):222-230.DOI:10.3969/j.issn.1005-202X.2016.03.002. [9] American Society for Testing and Materials (ASTM).Standard test method for measurement of magnetically induced displacement force on passive implants in the magnetic resonance environment[A]//Lukens RP.Annual book of ASTM standards section 13[M].Philadelphia,PA:ASTM,2002:1576-1580. [10] Shellock FG,Crues Ⅲ JV.MR safety and the American college of radiology white paper[J].AJR Am J Roentgenol,2002,178(6):1349-1352.DOI:10.2214/ajr.178.6.1781349. [11] Shellock FG,Kanal E.Aneurysm clips:evaluation of MR imaging artifacts at 1.5 T[J].Radiology,1998,209(2):563-566.DOI:10.1148/radiology.209.2.9807590. [12] Edwards MB,Taylor KM,Shellock FG.Prosthetic heart valves:evaluation of magnetic field interactions,heating,and artifacts at 1.5 T[J].J Magn Reson Imaging,2000,12(2):363-369.DOI:10.1002/1522-2586(200008)12:2<363::AID-JMRI21>3.0.CO;2-3. [13] Paley MNJ,Hart AR,Lait FM,et al. An MR-compatible neonatal incubator[J].Br J Radiol,2012,85(1015):952-958.DOI:10.1259/bjr/30017508. [14] Chen CC,Wan YL,Wai YY,et al. Quality assurance of clinical MRI scanners using ACR MRI phantom:preliminary results[J].J Digit Imaging,2004,17(4):279-284.DOI:10.1007/s10278-004-1023-5. [15] Weavers PT,Shu YH,Tao SZ,et al. Technical Note:compact three-tesla magnetic resonance imager with high-performance gradients passes ACR image quality and acoustic noise tests[J].Med Phys,2016,43(3):1259-1264.DOI:10.1118/1.4941362. [16] Jafar MM,Reeves J,Ruthven MA,et al. Assessment of a carbon fibre MRI flatbed insert for radiotherapy treatment planning[J].Br J Radiol,2016,89(1062):20160108.DOI:10.1259/bjr.20160108.
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