Digital tomosynthesis: a new paradigm for radiation treatment verification

数字断层合成：放射治疗验证的新范例

• 批准号: 7480200
• 负责人: Fang-Fang Yin
• 金额: $ 15.6万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-11 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7480200
• 关键词: 3-Dimensional; Abdomen; Anatomic Sites; Anatomy; Arts; Breast; Breathing; Chest; Clinic; Clinical; Conformal Radiotherapy; Daily; Data; Devices; Diagnostic; Dose; Evaluation; Exhibits; Future; Goals; Head and neck structure; Image; Imaging Techniques; Imaging technology; Immobilization; Implant; Intensity-Modulated Radiotherapy; Lead; Linear Accelerator Radiotherapy Systems; Location; Low Dose Radiation; Lung; Mammography; Measures; Mechanics; Methods; Motion; Noise; Organ; Outcome; Patients; Pelvis; Peripheral; Physicians; Pilot Projects; Procedures; Prostate; Radiation; Radiation Oncology; Radiation therapy; Range; Relative (related person); Resolution; Risk; Rotation; Scanning; Second Primary Neoplasms; Series; Site; Slice; Soft Tissue Neoplasms; Solutions; Specific qualifier value; Speed; Standards of Weights and Measures; Structure; Techniques; Technology; Time; Tissues; Translating; base; cone-beam computed tomography; design; digital; improved; innovation; prevent; reconstruction; respiratory; soft tissue; tool; tumor

DESCRIPTION (provided by applicant): Any deviation between treated and planned volume for 3-D conformal therapy, such as IMRT, may cause an adverse clinical outcome. It is therefore critical to minimize all potential deviations using an on-board (or real- time) procedure immediately prior to radiation delivery. At present, conventional 2-D radiographic imaging and state-of-the-art 3-D cone-beam CT (CBCT) are typically employed for treatment verification. However, 2-D radiographic verification is mainly based on bony structures and/or implanted fiducials, and is sub-optimal for soft-tissue targets. While on-board CBCT can provide 3-D soft tissue information, it has three major limitations: 1) The acquisition time is limited to 60 seconds (~15 breathing cycles) for on-board CBCT, makes single breath- hold imaging impractical for organs which exhibit respiratory motion; 2) 360o mechanical clearance for CBCT acquisition may limit the use of CBCT for large patients, those with tumors at peripheral locations (e.g. breast), or those with substantial immobilization or support devices; 3) A high radiation dose (2-9 cGy) is delivered to the imaged volume with current imaging techniques, which is undesirable for daily imaging and may be a particular problem for those who are at high risk of developing second malignancies. To overcome these limitations, we propose an innovative digital tomosynthesis (DTS) imaging technology for 3-D target localization. Although DTS technology has been used for digital chest and mammography, its use in target localization is unknown. DTS only requires limited gantry rotation (e.g., a scan angle of 40o or less) to reconstruct 3-D anatomic information. Thus, imaging time and dose are substantially reduced compared to CBCT, making breath-hold DTS a simple solution for daily imaging of moving organs. Further, the reduced mechanical clearance needed for DTS makes it more widely applicable than CBCT. At present, the localization accuracy using DTS technology in treatment verification remains unknown. This proposal hypothesizes that the target localization accuracy using DTS technology is better than 2-D radiographs and is comparable to CBCT but with less imaging time and dose, and better mechanical clearance. To validate this hypothesis, Aim #1 is intended to determine optimal DTS scan angles for 4 anatomic sites: head and neck, thorax, abdomen, and pelvis. A small scan angle is desirable for imaging efficiency but less desirable for image quality. Therefore, we will assess the impact of scan angle on (a) the DTS contrast-to-noise ratio and resolution in phantoms and (b) the mutual information shared between DTS and CBCT slices, using patient data from the 4 anatomic sites. In Aim #2, we will then quantitatively compare DTS- based target localization accuracy to that of 2-D radiographs and CBCT using patient data from the 4 anatomic sites. To achieve this goal, three physicians will measure relative shifts and rotations between reference and on- board images using 2-D, DTS, CBCT technologies. We anticipate that the DTS target localization accuracy will be equivalent to CBCT and an improvement over 2-D radiographic imaging. Yet, we expect DTS to be more practical, more efficient, and deliver lower dose than full CBCT for daily 3-D target localization. Accurate alignment of the radiation-therapy beam with the tumor target is essential for removing the tumor and for sparing surrounding healthy tissue. Currently, on-board cone-beam CT (CBCT) is the best method for aligning soft-tissue tumor, such as tumor in the breasts, lungs, or lower abdomen, yet use of CBCT in target localization in radiation therapy is restricted by its long acquisition time, its demanding mechanical clearance requirements, and its high radiation dose. Some are difficult to improve because there is a limitation of gantry rotation speed for conventional linear accelerators. The digital tomosynthesis (DTS) approach that we propose will provide more widely and more routinely applicable alignment of soft tissue, via much shorter acquisition time, much less mechanical constraint, and much lower radiation dose. This more frequent and broader range of application will translate into more consistent elimination of tumor and into less damage to nearby healthy tissue.

描述（由申请人提供）：三维适形治疗（如IMRT）的治疗体积和计划体积之间的任何偏差都可能导致不良临床结局。因此，在放射输送前立即使用机载（或真实的）程序最大限度地减少所有潜在偏差至关重要。目前，传统的2-D射线照相成像和最先进的3-D锥形束CT（CBCT）通常用于治疗验证。然而，2-D射线照相验证主要基于骨结构和/或植入的基准点，并且对于软组织目标是次优的。虽然机载CBCT可以提供3-D软组织信息，但它有三个主要限制：1）采集时间限制为60秒（~15个呼吸周期），使得单次屏气成像对于显示呼吸运动的器官不切实际; 2）CBCT采集的360 o机械间隙可能限制CBCT用于大型患者，即肿瘤位于外周位置的患者（例如，乳房），或具有实质性固定或支撑装置的那些; 3）用当前成像技术将高辐射剂量（2-9 cGy）递送到成像体积，这对于日常成像是不期望的，并且对于处于发展第二恶性肿瘤的高风险的那些人可能是特别的问题。为了克服这些局限性，我们提出了一种创新的数字断层合成（TOMO）成像技术的3-D目标定位。尽管数字化胸部和乳房X线摄影已使用了数字化胸部和乳房X线摄影技术，但其在目标定位中的用途尚不清楚。MEMS仅需要有限的机架旋转（例如，40 °或更小的扫描角度）以重建3D解剖信息。因此，与CBCT相比，成像时间和剂量大大减少，使屏气造影成为运动器官日常成像的简单解决方案。此外，减少机械间隙所需的CBCT使其更广泛地适用于比CBCT。目前，在治疗验证中使用RFID技术的定位精度仍然未知。该提案假设使用MRI技术的靶定位准确性优于2-D X线片，与CBCT相当，但成像时间和剂量更少，机械间隙更好。为了验证这一假设，目标1旨在确定4个解剖部位的最佳CT扫描角度：头颈部、胸部、腹部和骨盆。小的扫描角度对于成像效率是期望的，但是对于图像质量是不太期望的。因此，我们将使用来自4个解剖部位的患者数据，评估扫描角度对（a）体模中的CT对比噪声比和分辨率以及（B）CT和CBCT切片之间共享的交互信息的影响。在目标#2中，我们将使用来自4个解剖部位的患者数据，定量比较基于X线片的靶定位准确度与2-D X线片和CBCT的靶定位准确度。为了实现这一目标，三名医生将使用2-D、CT、CBCT技术测量参考图像和机载图像之间的相对位移和旋转。我们预计，三维目标定位精度将与CBCT相当，并优于2-D放射成像。然而，我们预计，对于日常3-D目标定位，CBCT将更实用，更有效，并且提供比全CBCT更低的剂量。放射治疗束与肿瘤靶的精确对准对于去除肿瘤和保护周围健康组织是必不可少的。目前，机载锥形束CT（CBCT）是对准软组织肿瘤（如乳腺、肺或下腹部肿瘤）的最佳方法，但CBCT在放射治疗中的靶定位中的使用受到其长采集时间、苛刻的机械间隙要求和高辐射剂量的限制。有些是难以改进的，因为传统的线性加速器的机架旋转速度有限制。我们提出的数字断层合成（Digital Tomosynthesis，简称TOM）方法将通过更短的采集时间、更少的机械约束和更低的辐射剂量，提供更广泛和更常规的软组织对准应用。这种更频繁和更广泛的应用将转化为更一致的肿瘤消除，并减少对附近健康组织的损害。

项目成果

Comparing digital tomosynthesis to cone-beam CT for position verification in patients undergoing partial breast irradiation.

• DOI: 10.1016/j.ijrobp.2008.10.036
• 发表时间: 2009-03-01
• 期刊: INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS
• 影响因子: 7
• 作者: Zhang, Junan;Wu, Jackie;Godfrey, Devon J.;Fatunase, Toyosi;Marks, Lawrence B.;Yin, Fang-Fang
• 通讯作者: Yin, Fang-Fang