肾细胞癌的立体定向体部放射治疗策略及进展

肾细胞癌(RCC)是泌尿生殖系统中侵袭性最高的恶性肿瘤之一,预后不佳,尤其是发生RCC转移的患者。传统观点一般认为肾细胞癌对放疗不敏感。立体定向体部放射治疗(SBRT)与常规放疗相比,具有高精准度、较高照射剂量、对周围组织损伤小等特点。近年来,SBRT在原发性及转移性RCC治疗中均展现了确切的疗效。SBRT联合靶向治疗以及免疫治疗等联合方案可以提高原发和晚期转移RCC患者的肿瘤局部控制率,且不良反应较小。本文就SBRT 联合靶向治疗以及免疫治疗的策略和进展等方面进行综述。     

A case study of DIBH to spare abdominal organs at risk for renal cell carcinoma MR-guided radiotherapy

Historically, respiratory induced motion has made renal radiotherapy difficult due to the potential risk of additional toxicities to the patient due to tumor movement. The use of deep inspiration breath holds (DIBH) in congruence with magnetic resonance guided radiotherapy (MRgRT) may be an effective method to manage tumor and organ at risk (OAR) motion and deliver radiation safer and more effectively. The purpose of this case study was to evaluate the effectiveness of DIBH in sparing radiation dose to colon and small bowel during MRgRT of right sided renal cell carcinoma (RCC). The goals were to reduce radiation dose to colon and small bowel during RCC treatment with these motion management techniques. A retrospective case study of a patient with oligoprogression in the postoperative renal fossa was found to be a candidate for DIBH using MRgRT. Treatment planning called for motion management and real-time imaging in order to safely treat the tumor volume. Results were evaluated by the achievement of specific dosimetric criteria and tolerances and the regression of disease in the renal fossa. The use of real-time imaging and simultaneous motion management proved to be effective tools for the treatment of RCC. This radiation therapy treatment resulted in the elimination of malignancy at the primary site of disease.     

肺癌立体定向放疗偏中心计划设计剂量学研究

目的研究不同程度的偏中心计划对肺癌立体定向放疗(SBRT)计划质量和执行准确度的影响, 为肺癌SBRT的临床计划设计提供参考。方法首先, 选取10例肺癌SBRT患者, 将计划等中心置于肿瘤质心位置, 设计等中心参考计划。将计划等中心置于偏离肿瘤质心1、3、5、8及10 cm位置, 设计偏中心计划, 共计60个, 分析这些偏中心计划相对于参考计划的剂量学差异。然后, 引入不同程度的位置误差(0～5 mm), 利用Octavius 4D高分辨率剂量验证系统, 测量这些计划的伽马通过率(GPR), 完成240次计划验证, 分析参考计划和偏中心计划的执行准确度对位置误差的鲁棒性。结果偏中心计划的剂量梯度指标略差于等中心计划, 差异无统计学意义(P>0.05)。随着偏中心距离增加, 正常肺平均剂量(MLD)和V20以及支气管Dmax略微有升高趋势。MLD在偏中心距离1、3和10 cm, 较等中心计划分别升高了0.8%、0.8%和1.9%, 差异具有统计学意义(z=-2.34～-1.99, P<0.05), V20在偏中心距离1、5和10 cm, 较等中心计划分别增加了2.0%、2.5...     

Solid renal mass in the cancer patient: second primary renal cell carcinoma versus renal metastasis

Most renal metastases are asymptomatic, occur with widespread metastatic disease, and are too small to be detected with computed tomography (CT). Rarely they form large masses. These are typically angiographically hypovascular and show only minimal CT contrast enhancement. Renal carcinoma as a second primary malignancy in the cancer patient is 4.5 times more common than mass-like renal metastases and demonstrates two CT contrast enhancement patterns. The latter include either minimal enhancement or irregular regions of intense enhancement. These CT contrast enhancement patterns of both renal carcinoma and metastasis can be used to direct the further diagnostic evaluation of these masses and distinguish between a renal metastasis or a second primary renal carcinoma in the cancer patient.     

Interobserver variability of patient positioning using four different CT datasets for image registration in lung stereotactic body radiotherapy

Purpose

To assess the impact of different reference CT datasets on manual image registration with free-breathing three-dimensional (3D) cone beam CTs (FB-CBCT) for patient positioning by several observers.

Methods

For 48 patients with lung lesions, manual image registration with FB-CBCTs was performed by four observers. A slow planning CT (PCT), average intensity projection (AIP), maximum intensity projection (MIP), and midventilation CT (MidV) were used as reference images. Couch shift differences between the four reference CT datasets for each observer as well as shift differences between the observers for the same reference CT dataset were determined. Statistical analyses were performed and correlations between the registration differences and the 3D tumor motion and the CBCT score were calculated.

Results

The mean 3D shift difference between different reference CT datasets was the smallest for AIPvsMIP (range 1.1–2.2?mm) and the largest for MidVvsPCT (2.8–3.5?mm) with differences >10?mm. The 3D shifts showed partially significant correlations to 3D tumor motion and CBCT score. The interobserver comparison for the same reference CTs resulted in the smallest ?3D mean differences and mean ?3D standard deviation for ?AIP (1.5 ± 0.7?mm, 0.7 ± 0.4?mm). The maximal 3D shift difference between observers was 10.4?mm (?MidV). Both 3D tumor motion and mean CBCT score correlated with the shift differences (R_s = 0.336–0.740).

Conclusion

The applied reference CT dataset impacts image registration and causes interobserver variabilities. The 3D tumor motion and CBCT quality affect shift differences. The smallest differences were found for AIP which might be the most appropriate CT dataset for image registration with FB-CBCT.

     

Dynamic hybrid-phase computed tomography simulation in lung stereotactic body radiotherapy: A feasibility study

To assess the feasibility of dynamic hybrid-phase computed tomography (CT_DHP) simulation when patients undergo lung stereotactic body radiation therapy (SBRT). Eighteen non-small-cell lung-cancer patients were immobilised in a stereotactic body frame with abdominal compression. All underwent dynamic hybrid-phase CT scans that were compared with cone-beam CT (CBCT). We also determined the internal target volume (ITV) and evaluated the following four metrics: the “AND” function in the Boolean module of Eclipse, volume overlap (VO), Dice similarity coefficient (DSC), and dose-volume histogram. The average ITV values of 4DCT_DHP and 3D-CBCT were respectively 12.82±10.42 and 14.6±12.18 cm³ (n=72, p<0.001), and the average ITV value of AND was 11.7±10.1 cm³. The average planning target volume (PTV) of 4DCT_DHP and 3D-CBCT was 25.63±18.04 and 28.00±19.82 cm³ (n=72, p<0.001). The median AND difference between ITV and PTV was significant (p<0.01) and had a significantly linear distribution (R²=0.991 for ITV, R²=0.972 for PTV). The average VO of PTV was greater than that of ITV (0.81±0.096; 0.78±0.11). We also observed that the average DSC in PTV (0.83±0.066) was greater than that in ITV (0.81±0.084). The average results indicated that 97.9%±3.44 of ITVCBCT was covered by 95% of the prescribed dose. The average minimum, maximum and mean percentage doses of ITV_CBCT were 87.9%±9.46, 107.3%±1.57, and 101.3%±1.12, respectively. This paper has demonstrated that dynamic hybrid-phase CT simulation for patients undergoing lung SBRT and also published evaluation metrics in scientific analysis. Our approach also has the advantage of adequate margin and fewer phases in CT simulation.     

射波刀治疗小肝癌前瞻性临床研究初步结果

目的 探讨射波刀-立体定向放疗技术治疗小肝癌的安全性和有效性。方法 前瞻性分析本院2014年6月至2016年12月应用立体定向放疗技术治疗33例小肝癌的患者资料,治疗后每3个月复查,采用修改后实体肿瘤疗效评价标准（mRECIST）进行疗效评价,采用常见不良反应事件评价标准（CTCAE）4.0分级标准评价治疗反应,采用Kaplan-Meier法计算生存率和局部控制（CR+PR+SD）率,并绘制生存曲线。结果 平均随访19.3（2.3~30.8）个月。截止随访日期,共有33个病例含33个靶点纳入研究。其中18个病灶（54.5%）完全缓解,7个病灶（21.2%）部分缓解,5个病灶（15.2%）稳定,3个（9.1%）进展。总有效（CR+PR）率为75.8%,局部控制率为90.9%。1年局部控制率为100%,2年局部控制率为83.6%,中位疾病无进展生存期（DPFS）为15.0个月。未照射肝脏体积≥ 1 000 ml、治疗前甲胎蛋白（AFP）<100 ng/ml、治疗后CTCAE分级≤ 1级均有助于延长生存期。V₅与2级及以上不良反应相关（P=0.015）。治疗后乏力、纳差、恶心、呕吐等胃肠道反应和肝损伤主要为1、2级不良反应,1例出现3级肝功能损伤在治疗半年后缓解,1例出现4级肝不良反应在治疗后1年治愈。结论 射波刀治疗小肝癌不良反应可耐受,局部控制效果好。     

Dosimetric impact of translational and rotational setup errors for spine stereotactic body radiotherapy: A phantom study

This study aimed to investigate experimentally the effect of translational and rotational setup errors on 3-dimensional dose distributions by using the gamma index and dose volumetric indices for spine stereotactic body radiotherapy. Treatment plans were designed in accordance with the Radiation Therapy Oncology Group (RTOG) 0631 protocol. Measurements were taken using a Delta4 phantom (ScandiDos, Uppsala, Sweden). Setup errors were generated using the HexaMotion 6D moving platform (ScandiDos). Dose distributions in the presence of setup errors were evaluated, according to the γ passing rate with the 3% and 2?mm criteria (γ_3%/2?mm) and dose volumetric indices (D₉₀ for the target volume and D₂ for the spinal cord), using the Delta4 device (ScandiDos). The sensitivity coefficient, which represented the correlation between the γ_3%/2?mm passing rate and dose volumetric indices, was determined to assess robustness against setup errors. Rotational setup errors of 2° were equivalent to translational setup errors of 2?mm for the γ_3%/2?mm passing rate, D₉₀ for the target, and D₂ for the spinal cord. D₉₀ for the target had low robustness against a translational setup error in the vertical direction and a rotational setup error in the pitch direction. D₂ for the spinal cord was sensitive to a translational setup error in the lateral direction and a rotational setup error in the roll direction. The positioning accuracy of the rotational setup error, corresponding to the tolerance level of image-guided radiotherapy in the RTOG 0631 protocol, was required to be?≤?2°.     

Imaging findings of ovarian metastasis of primary renal cell carcinoma: A case report and literature review

A 62-year-old woman presented with a tumor in the right kidney. A right partial nephrectomy was performed, and the tumor was diagnosed as clear cell renal cell carcinoma (RCC) on histopathological examination. A right ovarian tumor was detected on follow-up computed tomography (CT) 5 years after partial nephrectomy and pathology proved RCC metastasis. RCC rarely metastasizes to the ovaries. There is limited information on the radiological features of ovarian metastasis in RCC. In this case report, we presented the CT and magnetic resonance images of ovarian metastasis of RCC. In addition, we also presented a literature review with special emphasis on the imaging features of ovarian metastasis of RCC.     

Cochlea sparing with a stratified scheme of dose limitation employed in intensity-modulated radiotherapy for nasopharyngeal carcinoma: A dosimetry study

Hearing loss is 1 of the major complications after radiotherapy in nasopharyngeal carcinoma (NPC) patients, how to minimize dose to cochlea in order to reduce the incidence of sensorineural hearing loss is a critical task. This study is to investigate a stratified scheme of cochlea sparing based on T stage in intensity-modulated radiotherapy. We designed a comparison between 2 plans of cochlea sparing plan (C-Plan) and regular noncochlea sparing plan (R-Plan) from 19 NPC patients with 2, 3, 8, and 6 cases of T1, T2, T3, and T4 stage, respectively. The outcomes showed that target coverage parameters and dose-volume histogram features were of no significant difference, with a significant difference in dose distribution between C-Plan and R-Plan in cochlea and eustachian, e.g., ipsilateral cochlea D_mean 4619.75 ± 1134.09 cGy in C-Plan and 5061.03 ± 1121.09 cGy in R-Plan (p = 0.000), contralateral cochlea D_mean 4386.73 ± 945.14 cGy in C-Plan and 4991.38 ± 961.21 cGy in R-Plan (p = 0.000). Meanwhile, there was no significant difference in dose distribution in spinal cord, brainstem, and other OARs. Our dosimetry study showed cochlea sparing in intensity-modulated radiotherapy for NPC reduced cochlea dose to different extent, so we suggested a stratified scheme of cochlea sparing based on T stage could be a useful and practical tool for both physicists and radiation doctors.     

Influence of respiration on dose calculation in stereotactic body radiotherapy of the lung

Our purpose in this study was to evaluate the variation in calculated doses caused by respiration in stereotactic body radiotherapy (SBRT) of the lung. The study targeted ten patients who underwent SBRT for lung tumors. CT images were acquired during free breathing and in the inhalation and exhalation phases. We compared the CT image at inhalation with the image at exhalation so as to measure the change in lung volume, variation in the CT value, and displacement of the chest wall. The lung volume change was shown to be correlated with the maximum of the chest wall motion and with the variation in the CT value. A statistically significant difference was observed in the CT values between inhalation and exhalation (p < 0.05). The total dose variation at the isocenter was confined within ±2 %. However, the dose from individual beams can vary significantly when the chest wall moves more than 10 mm in natural breathing.     

鼻咽癌调强放疗中实施同一计划对剂量的影响

目的 探讨鼻咽癌调强放疗过程中实施同一治疗计划的可行性。方法 选10例采用调强放射治疗的鼻咽癌患者,用Pinnacle³制定IMRT计划。在患者放疗中期重新行CT定位扫描,把基于初次定位CT图像所做的IMRT计划复制到重新定位CT图像上,使得照射野参数保持一致,测得基于两套图像计划中的肿瘤靶区、脊髓、脑干和腮腺的受量。统计在整个放疗过程中如果实施同一计划,患者靶区及各器官的剂量变化率。结果 两组计划相比,等中心层面外轮廓左右和前后长度平均缩小8%、3%。靶区PTV₁(D₉₅)减少0.6%~5.3%;放疗中期和放疗前相比右侧和左侧腮腺体积分别缩小13.1%~41.4%、12.0%~49.0%;右侧和左侧腮腺平均剂量增加5.6%~45.1%、3.3%~32.2%;脊髓最大剂量变化为-4.1%~13.9%;脑干剂量变化为-3.9%~9.3%。结论 对于采用鼻咽癌调强放射治疗的患者,在不考虑摆位误差的影响因素下,由于靶区及正常组织显著变化等因素影响有重新定位修改计划的必要性。     

Improving the accuracy of motion quantification using area detector computed tomography for real-time tumor-tracking irradiation in stereotactic ablative radiotherapy

CyberKnife radiotherapy enables tumor-tracking irradiation using positional information regarding the tumor and a fiducial marker in a patient's body. This positional information acts as a surrogate of tumor motion. Therefore, deviations in these movements should be quantitatively estimated and included as an internal margin for radiation treatment planning. This study aimed to investigate variations between the positions of fiducial markers and tumor regions using 320-row area detector computed tomography and to analyze the effectiveness of our proposed method in contouring tumor regions based on the fiducial marker position. To determine the moving tumor volume, a typical single-phase image was selected, and pixel values in other phase images were accumulated. Moreover, a maximum-intensity projection image was created to clarify motion deviations in the tumor volume. To evaluate the delineation accuracy, the dice similarity coefficient and mean distance to agreement were calculated in phase-selected and breath-holding computed tomography. Moving chest phantom images were acquired using helical scanning 4-dimensional computed tomography (H-4DCT) and volumetric scanning 4-dimensional computed tomography (V-4DCT), and the delineation accuracies were compared for each scanning type. The average dice similarity coefficient and mean distance to agreement were degraded in limited-phase images, which cannot represent the hysteretic motion of a tumor. Moreover, deviations in tumor volume with unstable motion reached 71.6% in H-4DCT but only 1.6% in V-4DCT. Our proposed method with V-4DCT using area detector computed tomography can achieve accurate moving tumor delineation and can clarify positional associations between the fiducial marker and tumor under respiratory motion.     

A case of primary small cell neuroendocrine carcinoma of the uterus

Neuroendocrine carcinoma of the uterine endometrium is extremely rare and found in <1% of all primary endometrial carcinomas. We report a case of neuroendocrine carcinoma of the endometrium detected in a 65-year-old woman and focus our attention on the main imaging features. The low apparent diffusion coefficient value and high maximum standardized uptake value for neuroendocrine cancer serve to distinguish this cancer from endometrial cancer.