MRI-guided radiotherapy

MRI 引导放射治疗
  • 文章类型: Journal Article
    我们分析了在1.5TMRI指导下接受确定性前列腺放疗(RT)的患者的每日治疗前(PRE)和实时运动监测(MM)MRI扫描,以评估前列腺的切间和切内变异性,并建议最佳计划目标体积(PTV)边缘。
    根据骨盆骨和前列腺解剖,在PRE-MRI和计划CT图像之间进行了刚性配准。通过比较PRE-MRI上描绘的前列腺轮廓的质心值,评估了分数间设置裕度(SM)和观察者间变异性(IO)。MM-MRI用于内部余量(IM)评估,PTV裕度是使用范·赫克公式计算的。
    我们在PRE-MRI图像上描绘了400个前列腺轮廓。左右(LR)的SM分别为0.57±0.42、2.45±1.98和2.28±2.08mm,前-后(AP),和上-下(SI)方向,分别,骨定位后,LR为0.76±0.57、1.89±1.60和2.02±1.79mm,AP,和SI方向,分别,前列腺定位后。LR的IO值分别为1.06±0.58、2.32±1.08和3.30±1.85mm,AP,和SI方向,分别,骨定位后,LR为1.11±0.55、2.13±1.07和3.53±1.65mm,AP,和SI方向,分别,前列腺定位后。LR平均IM为2.12±0.86、2.24±1.07和2.84±0.88mm,AP,和SI方向,分别。LR中计算的PTV余量为2.21、5.16和5.40mm,AP,和SI方向,分别。
    SI方向的运动是确定性前列腺RT中变异性的最大来源,观察者间的变异性是一个不可忽视的边缘来源。最佳PTV裕度还应考虑内部裕度。
    UNASSIGNED: We analyzed daily pre-treatment- (PRE) and real-time motion monitoring- (MM) MRI scans of patients receiving definitive prostate radiotherapy (RT) with 1.5 T MRI guidance to assess interfractional and intrafractional variability of the prostate and suggest optimal planning target volume (PTV) margin.
    UNASSIGNED: Rigid registration between PRE-MRI and planning CT images based on the pelvic bone and prostate anatomy were performed. Interfractional setup margin (SM) and interobserver variability (IO) were assessed by comparing the centroid values of prostate contours delineated on PRE-MRIs. MM-MRIs were used for internal margin (IM) assessment, and PTV margin was calculated using the van Herk formula.
    UNASSIGNED: We delineated 400 prostate contours on PRE-MRI images. SM was 0.57 ± 0.42, 2.45 ± 1.98, and 2.28 ± 2.08 mm in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions, respectively, after bone localization and 0.76 ± 0.57, 1.89 ± 1.60, and 2.02 ± 1.79 mm in the LR, AP, and SI directions, respectively, after prostate localization. IO was 1.06 ± 0.58, 2.32 ± 1.08, and 3.30 ± 1.85 mm in the LR, AP, and SI directions, respectively, after bone localization and 1.11 ± 0.55, 2.13 ± 1.07, and 3.53 ± 1.65 mm in the LR, AP, and SI directions, respectively, after prostate localization. Average IM was 2.12 ± 0.86, 2.24 ± 1.07, and 2.84 ± 0.88 mm in the LR, AP, and SI directions, respectively. Calculated PTV margin was 2.21, 5.16, and 5.40 mm in the LR, AP, and SI directions, respectively.
    UNASSIGNED: Movements in the SI direction were the largest source of variability in definitive prostate RT, and interobserver variability was a non-negligible source of margin. The optimal PTV margin should also consider the internal margin.
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  • 文章类型: Journal Article
    扩散加权成像(DWI)允许询问组织细胞性,这是细胞增殖的替代品。先前尝试将DWI合并到0.35TMR直线加速器(MRL)的工作流程中的尝试缺乏定量准确性。在这项研究中,准确度,重复性,说明了在MRL系统上使用基于回波平面成像(EPI)的DWI协议产生的表观扩散系数(ADC)图的几何精度,并证明了患者纵向成像的体内潜力。
    通过在三个时间点测量扩散体模中的ADC值并与参考ADC值进行比较来评估准确性和可重复性。通过在0.35TMRL和3.0T诊断扫描仪上获取的ADC图上测量93对体模特征之间的距离,并与空间精确的CT图像进行比较,可以量化与系统相关的几何失真。此外,对于接受MRL放疗的五名肉瘤患者,在两个系统上都获得了同一天的体内ADC图,其中一个在多个时间点。
    PhantomADC定量在0.35TMRL上是准确的,仅在高ADC下观察到显着差异。对于MRL和诊断系统,中心切片的平均几何变形为0.35(±0.02)mm和0.85(±0.02)mm,在偏离中心5.4cm处的平均几何变形为0.66(±0.04)mm和2.14(±0.07)mm。分别。在肉瘤患者中,在MRL上测得平均预处理ADC为910x10-6(±100x10-6)mm2/s。
    获取精确,可重复,和几何精确的ADC图是可能的0.35T与EPI方法。
    UNASSIGNED: Diffusion weighted imaging (DWI) allows for the interrogation of tissue cellularity, which is a surrogate for cellular proliferation. Previous attempts to incorporate DWI into the workflow of a 0.35 T MR-linac (MRL) have lacked quantitative accuracy. In this study, accuracy, repeatability, and geometric precision of apparent diffusion coefficient (ADC) maps produced using an echo planar imaging (EPI)-based DWI protocol on the MRL system is illustrated, and in vivo potential for longitudinal patient imaging is demonstrated.
    UNASSIGNED: Accuracy and repeatability were assessed by measuring ADC values in a diffusion phantom at three timepoints and comparing to reference ADC values. System-dependent geometric distortion was quantified by measuring the distance between 93 pairs of phantom features on ADC maps acquired on a 0.35 T MRL and a 3.0 T diagnostic scanner and comparing to spatially precise CT images. Additionally, for five sarcoma patients receiving radiotherapy on the MRL, same-day in vivo ADC maps were acquired on both systems, one of which at multiple timepoints.
    UNASSIGNED: Phantom ADC quantification was accurate on the 0.35 T MRL with significant discrepancies only seen at high ADC. Average geometric distortions were 0.35 (±0.02) mm and 0.85 (±0.02) mm in the central slice and 0.66 (±0.04) mm and 2.14 (±0.07) mm at 5.4 cm off-center for the MRL and diagnostic system, respectively. In the sarcoma patients, a mean pretreatment ADC of 910x10-6 (±100x10-6) mm2/s was measured on the MRL.
    UNASSIGNED: The acquisition of accurate, repeatable, and geometrically precise ADC maps is possible at 0.35 T with an EPI approach.
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  • 文章类型: Journal Article
    背景:转移性胰腺导管腺癌(PDAC)的预后差,局部肿瘤进展的发病率高。我们调查了接受立体定向磁共振图像引导消融放疗(SMART)治疗原发性疾病的寡转移PDAC患者的结局。
    方法:我们对原发性肿瘤SMART诱导化疗期间诊断或异时寡转移PDAC的多机构回顾性分析。感兴趣的结果包括总生存期(OS),无进展生存期(PFS),免于局部失效(FFLRF),从遥远的失败(FFDF)自由。报告了急性和晚期毒性,在探索性分析中,根据转移数量对患者进行分层,智能指示,并增加转移导向治疗。
    结果:从2019年到2021年,22例寡转移PDAC患者(范围:1-6个转移)接受了SMART治疗原发性肿瘤,中位随访时间为SMART11.2个月。19例患者患有从头同步转移性疾病,3例患有异时少进展。转移部位最常见的是肝脏(40.9%),多个器官(27.3%),仅肺(13.6%),或腹部/盆腔淋巴结(13.6%)。所有患者均接受FOLFIRINOX(64%)或吉西他滨/nab-紫杉醇(36%),然后接受SMART(中位数50Gy,5个分数)用于局部控制(77%),疼痛控制(14%),或局部进展(9%)。此外,41%的患者接受其他转移导向治疗。诊断和SMART的中位OS分别为23.9个月和11.6个月,分别。根据SMART计算,中位PFS为2.4个月,91%的患者有远处进展,1年本地控制为68。两名患者(9%)经历了3级毒性,胃出口梗阻,和无4级或5级毒性的胃肠道出血。
    结论:在该寡转移PDAC队列中,SMART后局部疾病进展的发病率最低。随着全身治疗方案的改进,需要采用其他策略来确定可能从局部巩固或转移导向治疗中获益的患者.
    BACKGROUND: Metastatic pancreatic ductal adenocarcinoma (PDAC) carries a poor prognosis and significant morbidity from local tumor progression. We investigated outcomes among oligometastatic PDAC patients treated with stereotactic magnetic resonance image-guided ablative radiotherapy (SMART) to primary disease.
    METHODS: We performed a retrospective multi-institutional analysis of oligometastatic PDAC at diagnosis or with metachronous oligoprogression during induction chemotherapy treated with primary tumor SMART. Outcomes of interest included overall survival (OS), progression-free survival (PFS), freedom from locoregional failure (FFLRF), and freedom from distant failure (FFDF). Acute and late toxicity were reported and in exploratory analyses patients were stratified by the number of metastases, SMART indication, and addition of metastasis-directed therapy.
    RESULTS: From 2019 to 2021, 22 patients with oligometastatic PDAC (range: 1-6 metastases) received SMART to the primary tumor with a median follow-up of 11.2 months from SMART. Nineteen patients had de novo synchronous metastatic disease and three had metachronous oligoprogression. Metastasis location most commonly was liver only (40.9%), multiple organs (27.3%), lungs only (13.6%), or abdominal/pelvic nodes (13.6%). All patients received either FOLFIRINOX (64%) or gemcitabine/nab-paclitaxel (36%) followed by SMART (median 50 Gy, 5 fractions) for local control (77%), pain control (14%), or local progression (9%). Additionally, 41% of patients received other metastasis-directed treatments. The median OS from diagnosis and SMART was 23.9 months and 11.6 months, respectively. Calculated from SMART, the median PFS was 2.4 months with 91% of patients having distant progression, and 1-year local control was 68. Two patients (9%) experienced grade 3 toxicities, gastric outlet obstruction, and gastrointestinal bleed without grade 4 or 5 toxicity.
    CONCLUSIONS: There was minimal morbidity of local disease progression after SMART in this cohort of oligometastatic PDAC. As systemic therapy options improve, additional strategies to identify patients who may derive benefits from local consolidation or metastasis-directed therapy are needed.
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  • 文章类型: Journal Article
    背景:在腹部肿瘤的儿科放射治疗计划中,应用胰尾/脾的剂量限制来减少晚期毒性。在这项研究中,我们对胰尾/脾脏的运动间和运动内进行了分析,以评估在线MRI引导放射治疗(MRgRT)的潜在益处.
    方法:10名随机选择的神经母细胞瘤患者(中位年龄:3.4岁),在我们部门用强度调节电弧疗法照射(处方剂量:21.6/1.8Gy),回顾性评估胰尾/脾的运动间和运动内。三个随访MRI(T2和T1加权±g)与计划CT(pCT)严格配准,在目标体积周围的椎骨上。在所有MRI和pCT上描绘胰腺尾部/脾脏。分数运动定义为pCT和T2加权图像之间的重心变化在左右(LR),前后(AP)和颅尾(CC)方向。对于帧内运动分析,将T1加权±钆上的器官位置与T2加权进行比较。临床放射计划用于估计每个位置的胰尾/脾接收的剂量。
    结果:LR/AP的中位(IQR)分数运动最小,CC方向最大;胰尾2.5mm(8.9),和脾脏0.9毫米(3.9)。内交运动较小,但表现出类似的运动模式(胰腺尾巴,CC:0.4mm(1.6);脾脏,CC:0.9毫米(2.8))。与运动间和运动内运动相关的Dmean差异在胰腺尾部为-3.5至5.8Gy,在脾脏为-1.2至3.0Gy。在10个病人中有6个,由于违反≥1Gy的剂量限制,胰尾和脾的运动被强调为潜在的临床意义.
    结论:在随机选择的神经母细胞瘤队列中,在60%的神经母细胞瘤队列中,支持MRgRT的进一步前瞻性探索。
    BACKGROUND: In pediatric radiotherapy treatment planning of abdominal tumors, dose constraints to the pancreatic tail/spleen are applied to reduce late toxicity. In this study, an analysis of inter- and intrafraction motion of the pancreatic tail/spleen is performed to estimate the potential benefits of online MRI-guided radiotherapy (MRgRT).
    METHODS: Ten randomly selected neuroblastoma patients (median age: 3.4 years), irradiated with intensity-modulated arc therapy at our department (prescription dose: 21.6/1.8 Gy), were retrospectively evaluated for inter- and intrafraction motion of the pancreatic tail/spleen. Three follow-up MRIs (T2- and T1-weighted ± gadolinium) were rigidly registered to a planning CT (pCT), on the vertebrae around the target volume. The pancreatic tail/spleen were delineated on all MRIs and pCT. Interfraction motion was defined as a center of gravity change between pCT and T2-weighted images in left-right (LR), anterior-posterior (AP) and cranial-caudal (CC) direction. For intrafraction motion analysis, organ position on T1-weighted ± gadolinium was compared to T2-weighted. The clinical radiation plan was used to estimate the dose received by the pancreatic tail/spleen for each position.
    RESULTS: The median (IQR) interfraction motion was minimal in LR/AP, and largest in CC direction; pancreatic tail 2.5 mm (8.9), and spleen 0.9 mm (3.9). Intrafraction motion was smaller, but showed a similar motion pattern (pancreatic tail, CC: 0.4 mm (1.6); spleen, CC: 0.9 mm (2.8)). The differences of Dmean associated with inter- and intrafraction motions ranged from - 3.5 to 5.8 Gy for the pancreatic tail and - 1.2 to 3.0 Gy for the spleen. In 6 out of 10 patients, movements of the pancreatic tail and spleen were highlighted as potentially clinically significant because of ≥ 1 Gy dose constraint violation.
    CONCLUSIONS: Inter- and intrafraction organ motion results into unexpected constrain violations in 60% of a randomly selected neuroblastoma cohort, supporting further prospective exploration of MRgRT.
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  • 文章类型: Journal Article
    MRI引导放射治疗(MRIgRT)的技术进步改善了CT引导放射治疗的前列腺及其周围结构的实时可视化。精液研究表明,由于计划目标体积(PTV)边缘减少和治疗门控,通过MRIgRT的超小分割可实现安全的剂量增加。使用基于MRI的技术的桌上适应还可以结合目标形状和体积的实时变化,并且可以减少对可能进入治疗领域的敏感周围结构的高剂量辐射。正在进行的临床试验寻求使用MRIgRT改善前列腺癌的超小分割放射治疗。虽然这些研究有可能证明改善生化控制和减少副作用,有关患者治疗时间和操作工作流程的限制可能会妨碍在卓越中心之外广泛采用该技术。在这次审查中,我们讨论了MRIgRT治疗前列腺癌的优势和局限性,以及临床试验测试局部或前列腺切除术后复发性前列腺癌患者的疗效和毒性。
    Technological advances in MRI-guided radiation therapy (MRIgRT) have improved real-time visualization of the prostate and its surrounding structures over CT-guided radiation therapy. Seminal studies have demonstrated safe dose escalation achieved through ultrahypofractionation with MRIgRT due to planning target volume (PTV) margin reduction and treatment gating. On-table adaptation with MRI-based technologies can also incorporate real-time changes in target shape and volume and can reduce high doses of radiation to sensitive surrounding structures that may move into the treatment field. Ongoing clinical trials seek to refine ultrahypofractionated radiotherapy treatments for prostate cancer using MRIgRT. Though these studies have the potential to demonstrate improved biochemical control and reduced side effects, limitations concerning patient treatment times and operational workflows may preclude wide adoption of this technology outside of centers of excellence. In this review, we discuss the advantages and limitations of MRIgRT for prostate cancer, as well as clinical trials testing the efficacy and toxicity of ultrafractionation in patients with localized or post-prostatectomy recurrent prostate cancer.
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  • 文章类型: Journal Article
    我们的机构是世界上第一个在2014年临床上实施MR引导自适应放射治疗(MRgART)的机构。2021年,我们安装了CT引导的自适应放射治疗(CTgART)装置,成为世界上首批建立双模态ART诊所的诊所之一。在这里,我们回顾了导致开发大量双模态ART计划和治疗普查的因素,一年期间。
    我们机构的临床适应性服务启用了两种MRgART(MRIdian,ViewRay,Inc,山景,CA)和CTgART(ETHOS,瓦里安医疗系统,帕洛阿尔托,CA)平台。我们分析了患者和治疗信息,包括治疗的疾病部位,辐射剂量和分割,以及这两个平台上患者的治疗时间。此外,我们审查了我们的机构工作流程,验证,并在任一平台上实现新的自适应工作流。
    从2021年10月到2022年9月,256名患者在我们的机构接受了适应性治疗。186与MRgART和70与CTgART。接受MRgART治疗的大多数患者(106/186)患有胰腺癌,CTgART治疗最常见的部位是骨盆(23/70)和腹部(20/70)。MRgART平台上93.0%的治疗是立体定向放疗(SBRT),而CTgART平台上仅72.9%的治疗是SBRT.与MRgART平台相比,在CTgART平台上为腹部门控病例分配了更长的时间。而与MRgART平台相比,盆腔病例在CTgART平台上的时间更短.我们的适应性实施技术已导致使用MRgART的6项开放临床试验和使用CTgART的7项开放临床试验。
    我们展示了在我们的临床中成功开发双平台ART程序。需要不断的努力,以继续跨平台和疾病站点的ART的开发和整合,以最大程度地获取和证据。
    UNASSIGNED: Our institution was the first in the world to clinically implement MR-guided adaptive radiotherapy (MRgART) in 2014. In 2021, we installed a CT-guided adaptive radiotherapy (CTgART) unit, becoming one of the first clinics in the world to build a dual-modality ART clinic. Herein we review factors that lead to the development of a high-volume dual-modality ART program and treatment census over an initial, one-year period.
    UNASSIGNED: The clinical adaptive service at our institution is enabled with both MRgART (MRIdian, ViewRay, Inc, Mountain View, CA) and CTgART (ETHOS, Varian Medical Systems, Palo Alto, CA) platforms. We analyzed patient and treatment information including disease sites treated, radiation dose and fractionation, and treatment times for patients on these two platforms. Additionally, we reviewed our institutional workflow for creating, verifying, and implementing a new adaptive workflow on either platform.
    UNASSIGNED: From October 2021 to September 2022, 256 patients were treated with adaptive intent at our institution, 186 with MRgART and 70 with CTgART. The majority (106/186) of patients treated with MRgART had pancreatic cancer, and the most common sites treated with CTgART were pelvis (23/70) and abdomen (20/70). 93.0% of treatments on the MRgART platform were stereotactic body radiotherapy (SBRT), whereas only 72.9% of treatments on the CTgART platform were SBRT. Abdominal gated cases were allotted a longer time on the CTgART platform compared to the MRgART platform, whereas pelvic cases were allotted a shorter time on the CTgART platform when compared to the MRgART platform. Our adaptive implementation technique has led to six open clinical trials using MRgART and seven using CTgART.
    UNASSIGNED: We demonstrate the successful development of a dual platform ART program in our clinic. Ongoing efforts are needed to continue the development and integration of ART across platforms and disease sites to maximize access and evidence for this technique worldwide.
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  • 文章类型: Journal Article
    目的:由于其出色的软组织对比度和缺乏电离辐射,MRI越来越多地用于图像引导的放射治疗。然而,由梯度非线性(GNL)引起的几何畸变限制了解剖精度,可能影响肿瘤治疗的质量。此外,缓慢的MR采集和重建限制了有效图像引导的潜力。这里,我们展示了一种基于深度学习的方法,该方法可以从原始k空间数据中快速重建失真校正图像,用于MR引导的放射治疗应用。
    方法:我们利用可解释展开网络的最新进展来开发失真校正重建网络(DDConecNet),该网络应用卷积神经网络(CNN)来学习有效的正则化和非均匀快速傅里叶变换用于GNL编码。DCReconNet在来自11名健康志愿者的公共MR大脑数据集上进行了全面采样和加速技术训练,包括并行成像(PI)和压缩传感(CS)。在幻影上测试了DCReconNet的性能,大脑,骨盆,和在1.0TMRI-直线加速器上获得的肺部图像。DCReconNet,CS-,通过结构相似性(SSIM)和RMS误差(RMSE)测量基于PI和UNet的重建图像质量,以进行数值比较。还报告了每种方法的计算时间和残余失真。
    结果:成像结果表明,与基于CS和PI的重建方法相比,DCReconNet更好地保留了图像结构。DCReconNet在模拟脑图像上以四倍的加速度产生最高的SSIM(0.95中值)和最低的RMSE(<0.04)。DCReconNet比迭代快10倍以上,正则化重建方法。
    结论:DCReconNet提供了快速和几何精确的图像重建,并具有用于MRI引导放射治疗应用的潜力。
    MRI is increasingly utilized for image-guided radiotherapy due to its outstanding soft-tissue contrast and lack of ionizing radiation. However, geometric distortions caused by gradient nonlinearities (GNLs) limit anatomical accuracy, potentially compromising the quality of tumor treatments. In addition, slow MR acquisition and reconstruction limit the potential for effective image guidance. Here, we demonstrate a deep learning-based method that rapidly reconstructs distortion-corrected images from raw k-space data for MR-guided radiotherapy applications.
    We leverage recent advances in interpretable unrolling networks to develop a Distortion-Corrected Reconstruction Network (DCReconNet) that applies convolutional neural networks (CNNs) to learn effective regularizations and nonuniform fast Fourier transforms for GNL-encoding. DCReconNet was trained on a public MR brain dataset from 11 healthy volunteers for fully sampled and accelerated techniques, including parallel imaging (PI) and compressed sensing (CS). The performance of DCReconNet was tested on phantom, brain, pelvis, and lung images acquired on a 1.0T MRI-Linac. The DCReconNet, CS-, PI-and UNet-based reconstructed image quality was measured by structural similarity (SSIM) and RMS error (RMSE) for numerical comparisons. The computation time and residual distortion for each method were also reported.
    Imaging results demonstrated that DCReconNet better preserves image structures compared to CS- and PI-based reconstruction methods. DCReconNet resulted in the highest SSIM (0.95 median value) and lowest RMSE (<0.04) on simulated brain images with four times acceleration. DCReconNet is over 10-times faster than iterative, regularized reconstruction methods.
    DCReconNet provides fast and geometrically accurate image reconstruction and has the potential for MRI-guided radiotherapy applications.
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  • 文章类型: Journal Article
    UNASSIGNED: To identify any clinical or dosimetric parameters that predict which individuals may benefit from on-table adaptation during pancreas stereotactic body radiotherapy (SBRT) with MRI-guided radiotherapy.
    UNASSIGNED: This was a retrospective study of patients undergoing MRI-guided SBRT from 2016 to 2022. Pre-treatment clinical variables and dosimetric parameters on the patient\'s simulation scan were recorded for each SBRT course, and their ability to predict for on-table adaptation was analyzed using ordinal logistic regression. The outcome measure was number of fractions adapted.
    UNASSIGNED: Sixty-three SBRT courses consisting of 315 fractions were analyzed. Median prescription dose was 40 Gy in five fractions (range, 33-50 Gy); 52% and 48% of courses were prescribed ≤40 Gy and >40 Gy, respectively. The median minimum dose delivered to 95% (D95) of the gross tumor volume (GTV) and planning target volume (PTV) was 40.1 Gy and 37.0 Gy, respectively. Median number of fractions adapted per course was three, with 58% (183 out of 315) total fractions adapted. On univariable analysis, the prescription dose (>40 Gy vs ≤40 Gy), GTV volume, stomach V20 and V25, duodenum V20 and dose maximum, large bowel V33 and V35, GTV dose minimum, PTV dose minimum, and gradient index were significant determinants for adaptation (all p < 0.05). On multivariable analysis, only the prescription dose was significant (adjusted odds ratio 19.7, p = 0.005), but did not remain significant after multiple test correction (p = 0.08).
    UNASSIGNED: The likelihood of needing on-table adaptation could not be reliably predicted a priori using pre-treatment clinical characteristics, dosimetry to nearby organs at risk, or other dosimetric parameters based on the patient\'s anatomy at the time of simulation, suggesting the critical importance of day-to-day variations in anatomy and increasing access to adaptive technology for pancreas SBRT. A higher (ablative) prescription dose was associated with increased use of adaptation.
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  • 文章类型: Journal Article
    近十年来,磁共振成像(MRI)已成为放射治疗领域的重要成像方式,特别是随着各种新型MRI和图像引导技术的发展。在这篇评论文章中,我们将描述最近的发展,并讨论多参数MRI(mpMRI)在RT模拟中的应用。在这次审查中,mpMRI是指包括各种多对比MRI技术的一般和宽松的定义。具体来说,我们将专注于实施,RT模拟MPMRI技术的挑战和未来方向。本文受版权保护。保留所有权利。
    Magnetic resonance imaging (MRI) has become an important imaging modality in the field of radiotherapy (RT) in the past decade, especially with the development of various novel MRI and image-guidance techniques. In this review article, we will describe recent developments and discuss the applications of multi-parametric MRI (mpMRI) in RT simulation. In this review, mpMRI refers to a general and loose definition which includes various multi-contrast MRI techniques. Specifically, we will focus on the implementation, challenges, and future directions of mpMRI techniques for RT simulation.
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  • 文章类型: Journal Article
    未经评估:磁共振引导放射治疗(MRgRT)的使用在全球范围内迅速扩大,由包括连续传输内可视化在内的高级功能驱动,自动触发光束传递,和表内自适应重新规划(OART)。我们的目标是描述这种新技术的早期采用者在美国(US)使用0.35Tesla(T)-MRgRT(MRIdian)的模式。
    UNASSIGNED:为2014年至2020年完成治疗的患者提取了来自所有美国MRIdian治疗系统的匿名管理数据。所有MRIdian直线加速器(直线加速器)系统和一些钴系统均可获得详细的治疗信息。
    UNASSIGNED:16个中心的17个系统提供了5736个疗程和36,389个馏分(1223个钴疗程无法提供馏分详细信息),其中21.1%是适应的。在所有疗程的70.3%中使用了超分馏(UHfx)(1-5个馏分)。38.5%的课程至少使用了一个适应分数(平均1.7个适应分数/课程),在UHfx剂量计划中使用较高的oART(47.7%的疗程,平均每道菜1.9个适应分数)。最常治疗的器官部位是胰腺(20.7%),肝脏(16.5%),前列腺(12.5%),乳房(11.5%),和肺(9.4%)。时间趋势显示,治疗疗程的复合年增长率(CAGR)为59.6%,到2020年,UHfx的使用急剧增加,占课程的84.9%,oART的使用类似增加,占课程的51.0%。
    UNASSIGNED:这是首次报告美国早期采用MRIdian的使用模式的综合研究。帧内MR图像引导,先进的运动管理,越来越多的适应性放射治疗已经导致了向超小分割方案的实质性过渡。0.35T-MRgRT已主要用于治疗腹部和骨盆肿瘤,并越来越多地使用桌上适应性重新计划,这代表了放射治疗的范式转变。
    UNASSIGNED: Magnetic resonance-guided radiation therapy (MRgRT) utilization is rapidly expanding worldwide, driven by advanced capabilities including continuous intrafraction visualization, automatic triggered beam delivery, and on-table adaptive replanning (oART). Our objective was to describe patterns of 0.35Tesla(T)-MRgRT (MRIdian) utilization in the United States (US) among early adopters of this novel technology.
    UNASSIGNED: Anonymized administrative data from all US MRIdian treatment systems were extracted for patients completing treatment from 2014 to 2020. Detailed treatment information was available for all MRIdian linear accelerator (linac) systems and some cobalt systems.
    UNASSIGNED: Seventeen systems at 16 centers delivered 5736 courses and 36,389 fractions (fraction details unavailable for 1223 cobalt courses), of which 21.1% were adapted. Ultra-hypofractionation (UHfx) (1-5 fractions) was used in 70.3% of all courses. At least one adaptive fraction was used for 38.5% of courses (average 1.7 adapted fractions/course), with higher oART use in UHfx dose schedules (47.7% of courses, average 1.9 adapted fractions per course). The most commonly treated organ sites were pancreas (20.7%), liver (16.5%), prostate (12.5%), breast (11.5%), and lung (9.4%). Temporal trends show a compounded annual growth rate (CAGR) of 59.6% in treatment courses delivered, with a dramatic increase in use of UHfx to 84.9% of courses in 2020 and similar increase in use of oART to 51.0% of courses.
    UNASSIGNED: This is the first comprehensive study reporting patterns of utilization among early adopters of MRIdian in the US. Intrafraction MR image-guidance, advanced motion management, and increasing adoption of adaptive radiation therapy has led to a substantial transition to ultra-hypofractionated regimens. 0.35 T-MRgRT has been predominantly used to treat abdominal and pelvic tumors with increasing use of on-table adaptive replanning, which represents a paradigm shift in radiation therapy.
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