乳腺癌改良根治术后放疗降低患侧肺受量的剂量学研究

目的 探讨乳腺癌改良根治术后放疗(PMRT)3种照射技术靶区和患侧肺剂量分布的特点,评价其对降低患侧肺受量的作用。方法 对28例Ⅱ、Ⅲ期乳腺癌根治术后患者分别进行胸壁区2个切线适形野(半野)加锁骨上区调强放疗(3D-CRT+IMRT)、胸壁区加锁骨上区一体调强放疗(IMRT),以及胸壁区2个切线适形野(半野)加锁骨上区电子线单野放疗技术(3D-CRT+E)的计划设计,通过剂量体积直方图(DVH)评价靶区剂量以及患侧肺V₅、V₁₀、V₂₀及V45受照射体积,处方剂量为50.4 Gy(1.8 Gy × 28次)。结果 靶区适形指数(CI)3D-CRT+IMRT组(0.61±0.03)和IMRT组(0.62±0.03)之间差异无统计学意义(q=2.16, P>0.05),这两组CI均优于 3DCRT+E组[(0.44±0.02), q=20.50、 22.66,P<0.01];不均匀指数(HI) 3D-CRT+IMRT组 (1.17±0.02)和IMRT组(1.15±0.02)之间差异无统计学意义(q=1.66, P>0.05),这两组HI均优于 3DCRT+E 组[(1.24±0.04), q=3.91、5.58, P<0.01];患侧肺V₅ 、V₁₀,3D-CRT+E组(48.70%±3.24%, 38.56%±3.70%)、3D-CRT+IMRT组(49.12%±3.03%,38.38%±3.56%)明显少于IMRT组[(77.18%±8.01%, 53.07%±6.85%),q=20.35、20.05、12.10、12.24, P<0.01],3D-CRT+E、3D-CRT+IMRT两组之间差异无统计学意义(q=0.30、0.14, P＞0.05);患侧肺V₂₀,3D-CRT+IMRT组(26.57%±2.51%)、IMRT组(25.22%±2.77%)优于3D-CRT+E组[(31.79%±3.00%), q=5.27、8.21, P<0.01],3D-CRT+IMRT、IMRT两组之间差异无统计学意义(q=2.76, P＞0.05);V453种计划之间差异无统计学意义(F=0.69, P＞0.05)。结论 在PMRT中应用3D-CRT+IMRT照射技术在不增加设备投入的情况下能有效地降低患侧肺受照射剂量。     

Evaluation of bolus electron conformal therapy compared with conventional techniques for the treatment of left chest wall postmastectomy in patients with breast cancer

Postmastectomy radiation (PMRT) lowers local-regional recurrence risk and improves survival in selected patients with breast cancer. The chest wall and lower axilla are technically challenging areas to treat with homogenous doses and normal tissue sparing. This study compares several techniques for PMRT to provide data to guide selection of optimal treatment techniques. Twenty-five consecutive left-sided patients treated postmastectomy were contoured using Radiation Therapy Oncology Group (RTOG) atlas guidelines then planned using 4 different PMRT techniques: opposed tangents with wedges (3-dimensional [3D] wedges), opposed tangents with field-in-field (FiF) modulation, 8-field intensity modulation radiotherapy (IMRT), and custom bolus electron conformal therapy (BolusECT, .decimal, Inc., Sanford, FL). Required planning target volume (PTV) coverage was held constant, and then dose homogeneity and normal tissue dose parameters were compared among the 4 techniques. BolusECT achieved clincally acceptable PTV coverage for 22 out of 25 cases. Compared with either tangential technique, IMRT and BolusECT provided the lowest heart V₂₅ doses (3.3% ± 0.9% and 6.6% ± 3.2%, respectively with p < 0.0001). FiF had the lowest mean total lung dose (7.3 ± 1.1 Gy, with p = 0.0013), IMRT had the lowest total lung V₂₀ (10.3% ± 1.6%, p < 0.0001), and BolusECT had the lowest mean heart dose (7.3 ± 2.0 Gy, p = 0.0002). IMRT provided the optimal dose homogeneity and normal tissue sparing compared with all other techniques for the cases in which BolusECT could not achieve acceptable PTV coverage. IMRT generally exposes contralateral breast and lung to slightly higher doses. Optimal PMRT technique depends upon patient anatomy. Patients whose maximal target volume depth is about 5.7 cm or less can be treated with BolusECT-assisted 12 or 15 MeV electron beams. At these energies, BolusECT has comparable dose-volume statistics as IMRT and lower heart V₂₅ than opposed tangential beams. Patients with larger depths are best treated with IMRT, which provides significant advantages in both dose homogeneity and normal tissue sparing compared with all other techniques.     

An in silico comparative dosimetric study of postmastectomy locoregional irradiation using intensity-modulated vs 3-dimensional conventional radiotherapy

An in silico dosimetric evaluation of intensity-modulated radiation therapy (IMRT) vs 3-dimensional conventional radiation therapy (3D-CRT) treatment plans in postmastectomy radiation therapy (PMRT) to the chest wall and regional lymphatics was conducted. Twenty-five consecutive patients with breast cancer referred for locoregional PMRT, stages T_2-4 with N_1-3, were planned to receive 50?Gy in 25 fractions with IMRT. Additionally, a 3D-CRT plan was generated using identical contours for the clinical target volumes (CTV), planning target volumes (PTV), and organs at risk (OAR). Treatment plans were assessed using dose-volume histogram (DVH) parameters of D₉₈, D₉₅, D₅₀, D₂, and homogeneity index for individual CTVs and PTVs. OARs evaluated were ipsilateral and contralateral lungs, heart, spinal cord, and opposite breast. Most DVH parameters pertaining to CTVs and PTVs significantly favored IMRT. V₂₀ for ipsilateral and contralateral lungs, D₃₃ of heart and maximum dose to spinal cord favored IMRT (all p?<?0.001). The mean dose to the opposite breast was significantly lesser with 3D-CRT (5.8?±?1.8?Gy vs 2.0?±?1.0?Gy, p?<?0.001). Thus, except for the mean dose to the opposite breast, the compliance to DVH constraints applied to PTV and OARs were significantly better with IMRT. At a median follow-up of 76 months (7-91), none had locoregional failure or pulmonary or cardiac morbidity. For PMRT, requiring comprehensive irradiation to both chest wall and regional lymphatics, IMRT offers superior dosimetric advantages over 3D-CRT. This was also corroborated by long-term outcomes in these patients treated with IMRT.     

Time-driven activity-based costing of a novel form of CT-guided high-dose-rate brachytherapy intraoperative radiation therapy compared with conventional breast intraoperative radiation therapy for early stage breast cancer

IntroductionIntraoperative radiation therapy is an emerging option for adjuvant therapy for early stage breast cancer, although it is not currently considered standard of care in the United States. We applied time-driven activity-based costing to compare two alternative methods of breast intraoperative radiation therapy, including treatment similar to the techniques employed in the TARGIT-A clinical trial and a novel version with CT-guidance and high-dose-rate (HRD) brachytherapy.Methods and MaterialsProcess maps were created to describe the steps required to deliver intraoperative radiation therapy for early stage breast cancer at each institution. The components of intraoperative radiation therapy included personnel, equipment, and consumable supplies. The capacity cost rate was determined for each resource. Based on this, the delivery costs were calculated for each regimen. For comparison across centers, we did not account for indirect facilities costs and interinstitutional differences in personnel salaries.ResultsThe CT-guided, HRD form of intraoperative radiation therapy costs more to deliver ($4,126.21) than the conventional method studied in the TARGIT-A trial ($1,070.45). The cost of the brachytherapy balloon applicator ($2,750) was the primary driver of the estimated differences in costs. Consumable supplies were the largest contributor to the brachytherapy-based approach, whereas personnel costs were the largest contributor to costs of the standard form of intraoperative radiation therapy.ConclusionsWhen compared with the more established method of intraoperative radiation therapy using a portable superficial photon unit, the delivery of treatment with CT guidance and HDR brachytherapy is associated with substantially higher costs. The excess costs are driven primarily by the cost of the disposable brachytherapy balloon applicator and, to a lesser extent, additional personnel costs. Future work should include evaluation of a less expensive brachytherapy applicator to increase the anticipated value of brachytherapy-based intraoperative radiation therapy.     

Risk analysis of electronic intraoperative radiation therapy for breast cancer

PurposeTo evaluate the process and improve safety of intraoperative radiation therapy (IORT) for early-stage breast cancers treated with electronic brachytherapy.Methods and MaterialsA multidisciplinary team conducted a failure mode and effects analysis (FMEA) for IORT breast cancer treatments by first developing a process map. This map was then used to identify failure modes for all steps in the treatment workflow. Risk priority numbers (RPNs) were assigned to each failure mode and were calculated as the product of the failure mode's probability of occurrence (O), severity (S), and lack of detectability (D). Corrective steps were implemented to address failure modes with the highest risk, and a revised process was generated.ResultsThe steps with the highest risk failure modes were related to source calibration, use of correct plan and dwell times, and the correct site and intent. The introduction of a physician calibration check and an extended time-out checklist reduced the risk of these failure modes. The highest risk steps in the Xoft breast IORT treatment process are associated with source calibration and manual entry of dwell positions for each balloon size and volume combination. High-risk failure modes that could be mitigated with improved hardware and software interlocks were identified.ConclusionHigh-risk failure modes are identified with FMEA and addressed with corrective steps. This application of FMEA can be used in principle for clinical processes throughout breast cancer care. This analysis demonstrates the importance of well-designed QC policies, procedures, and oversight in a Xoft electronic brachytherapy program for breast cancer IORT.     

Adaptive radiation therapy of breast cancer by repeated imaging during irradiation

Breast cancer is the most frequent cancer among females and also a leading cause of cancer related mortality worldwide. A multimodality treatment approach may be utilized for optimal management of patients with combinations of surgery, radiation therapy (RT) and systemic treatment. RT composes an integral part of breast conserving treatment, and is typically used after breast conserving surgery to improve local control. Recent years have witnessed significant improvements in the discipline of radiation oncology which allow for more focused and precise treatment delivery. Adaptive radiation therapy (ART) is among the most important RT techniques which may be utilized for redesigning of treatment plans to account for dynamic changes in tumor size and anatomy during the course of irradiation. In the context of breast cancer, ART may serve as an excellent tool for patients receiving breast irradiation followed by a sequential boost to the tumor bed. Primary benefits of ART include more precise boost localization and potential for improved normal tissue sparing with adapted boost target volumes particularly in the setting of seroma reduction during the course of irradiation. Herein, we provide a concise review of ART for breast cancer in light of the literature.     

乳腺癌术后胸壁大体积复发二野和六野调强放疗剂量学比较

目的 比较乳腺癌术后胸壁大体积复发2野和6野调强放疗的计划差异.方法 对8例乳腺切除术后胸壁大体积复发病例,Pinnacle计划系统上分别对PTV进行2野调强和6野调强放疗计划设计,PTV处方剂量为50 Gy/25次(GTV后续计划补量至66～70 Gy),比较2种计划95％处方剂量PTV适形指数(CI)、均匀性指数(HI)及心脏、同侧肺剂量.结果 6野IMRT计划的CI和HI均优于2野IMRT计划,6野和2野的CI分别为(0.66±0.08)和(0.53±0.10)(t=7.99,P＜0.05),HI分别为(1.36±0.08)和(2.19±0.78)(t=9.04,P＜0.05).2个计划中肺V5、V10、V20、V35和心脏Dmax、V35、Dmean值比较差异无统计学意义.结论 乳腺癌切除术后胸壁大体积复发患者行放疗,6野静态逆向调强放疗计划靶区覆盖优于2野,而心肺受量方面无明显差异.     

Therapeutic potential of melatonin for breast cancer radiation therapy patients

Melatonin is an endogenous hormone primarily known for its action on the circadian rhythms. But pre-clinical studies are reporting both its radioprotective and radiosensitizing properties, possibly mediated through an interaction between melatonin and the regulation of estrogens. Melatonin pre-treatment prior to ionizing radiation was associated with a decrease in cell proliferation and an increase in p53 mRNA expression, leading to an increase in the radiosensitivity of breast cancer cells. At the same time, a decrease in radiation-induced side effects was described in breast cancer patients and in rodent models. This review examines the potential for melatonin to improve the therapeutic outcomes of breast radiation therapy, specifically estrogen receptor positive patients. Evidence suggests that melatonin may offer a novel, non-toxic and cheap adjuvant therapy to improve the existing treatment modalities. But further research is required in the clinical setting before a clear understanding of its therapeutic benefits is determined.     

Field-in-field plan does not improve the dosimetric outcome compared with the wedged beams plan for breast cancer radiotherapy

To evaluate and compare the dosimetry of field-in-field (FIF) and wedged beams (WB) techniques for patients with breast cancer receiving adjuvant radiotherapy after conservative surgery. A total of 89 patients with breast cancer participated in this study. Each patient received a computed tomography–based treatment plan with opposed tangential fields. Two planning techniques (FIF and WB) were generated for each patient by using the Pinnacle treatment-planning system. Three indices, the homogeneity index (HI), conformity index (CI), and uniformity index (UI), as well as maximum dose (D_max), median dose (D₅₀), number of portals, monitor unit (MU), and lung volume at 20 Gy (lung₂₀) were used for comparison. The mean values tested using a t-test indicated that the WB technique had a significantly lower HI (p < 0.0001), a significantly higher CI (p < 0.0001), and a significantly higher D₅₀ (p = 0.0002) than did the FIF technique. The FIF technique had a significantly higher D_max compared with the WB technique, but lung₂₀ did not exhibit a significant difference. By contrast, the FIF technique had a significantly higher UI and a significantly lower MU compared with the WB technique, but a significantly higher number of portals were found in the FIF technique. The FIF technique did not demonstrate superior dosimetric results. The WB technique had a significantly lower HI, higher CI, lower D_max, and lower number of portals; but the FIF technique had a significantly higher UI and lower MU.     

Postoperative radiation therapy for carcinoma of the uterine cervix

Postoperative radiation therapy (PORT) for cervical cancer has been empirically performed for patients with pathologic risk factors for recurrence after surgery. The efficacy of PORT is mainly supported by retrospective studies. Despite convincing evidence demonstrating a reduction in pelvic recurrence rates when PORT is employed, there is no evidence that it eventually improves patient survival. Local recurrence, such as vaginal stump recurrence, is not always fatal if diagnosed earlier. Some patients, unfortunately, may develop distant metastases even after PORT. The positive effects of PORT also may be counterbalanced by increased toxicities that result from combining local therapies. These factors obscure the efficacy of PORT for cervical cancer patients. There has been no consensus on the predictive value of risk factors for recurrence, which renders indication of PORT for early-stage cervical cancer quite variable among institutions. Today, efforts have been made to divide patients into three risk groups based on the combination of risk factors present after radical hysterectomy. In Europe/USA and Japan, however, a fundamental difference exists in the indications for radical surgery, highlighting differences in the concept of PORT; “adjuvant pelvic irradiation after stage IB-IIA patients after complete resection” in Europe/USA and “pelvic irradiation after surgery irrespective of initial clinical stage and surgical margin status” in Japan. Thus, it is questionable whether scientific evidence established in Europe/USA is applicable to Japanese clinical practice. The purpose of this article is to review the role of PORT by interpreting the results of clinical studies. The contents of the current article were presented as an educational lecture on the 64^th JRS meeting (April 2005) in Yokohama.     

Early active extension after anterior cruciate ligament reconstruction does not result in increased laxity of the knee

If permission of full active and passive extension immediately after an anterior cruciate ligament (ACL) reconstruction will increase the post-operative laxity of the knee has been a subject of discussion. We investigated whether a post-operative rehabilitation protocol including active and passive extension without any restrictions in extension immediately after an ACL reconstruction would increase the post-operative anterior–posterior knee laxity (A–P laxity). Our hypothesis was that full active and passive extension immediately after an ACL reconstruction would have no effect on the A–P laxity and clinical results up to 2 years after the operation. Twenty-two consecutive patients (14 men, 8 women, median age 21 years, range 17–41) were included. All the patients had a unilateral ACL rupture and no other ligament injuries or any other history of previous knee injuries. The surgical procedure was identical in all patients and one experienced surgeon operated on all the patients, using the bone-patellar tendon-bone autograft. The post-operative rehabilitation programme was identical in both groups, except for extension training during the first 4 weeks post-operatively. The patients were randomly allocated to post-operative rehabilitation programmes either allowing (Group A, n=11) or not allowing [Group B (30 to −10°), n=11] full active and passive extension immediately after the operation. They were evaluated pre-operatively and at 6 months and 2 years after the reconstruction. To evaluate the A–P knee laxity, radiostereometric analysis (RSA) and KT-1000 arthrometer (KT-1000) measurements were used, range of motion, Lysholm score, Tegner activity level, the International Knee Documentation Committee (IKDC) evaluation system and one-leg-hop test quotient were used. Pre-operatively, the RSA measurements revealed side-to-side differences in Group A of 8.6 mm (2.3–15.4), median (range) and in Group B of 7.2 mm (2.2–17.4) (n.s.). The corresponding KT-1000 values were for Group A, 2.0 mm (0–8.0) and Group B, 4.0 mm (0–10.0) (n.s.). At 2 years, the differences between the two groups were minimal, regardless of the method that had been used. The RSA measurements in Group A were 2.7 mm (0–10.7) and in Group B 2.8 (−1.8 to 9.5). The KT-1000 values were for Group A, 1.0 mm (−1.5 to 3.5), and for Group B, 0.5 mm (−1.0 to 4.0), without any significant differences between the groups. Nor did the Lysholm score, Tegner activity level, IKDC or one-leg-hop test differ. Early active and passive extension training, without any restrictions in extension, immediately after an ACL reconstruction using bone-patellar tendon-bone graft did not increase post-operative knee laxity up to 2 years after the ACL reconstruction.     

电离辐射联合肿瘤坏死因子相关凋亡诱导配体对乳腺癌MCF-7细胞株作用的研究

目的 探讨肿瘤坏死因子相关凋亡诱导配体（TRAIL）对人乳腺癌MCF．7细胞株的作用以及与放射治疗联合的可行性。方法1×10^4／ml MCF-7细胞接种至96孔板培养后加入不同浓度的TRAIL、给予不同剂量照射及TRAIL与电离辐射联合，Mrrr法检测细胞抑制率。MCF-7细胞接种至6孔板培养后，分别加入TRAIL（1μg／ml）、给予8Gy照射及TRAIL与8Gy照射联合，流式细胞术检测不同处理组细胞的凋亡率。应用RT-PCR法检测经不同处理后的细胞凋亡相关基因的表达情况。结果TRAIL（1μg／ml）与4、8和12Gy照射联合后对细胞的抑制率明显增加，与单独应用TRAIL及单独照射相比，差异有统计学意义。RT-PCR结果显示Bcl-2、Bcl-Xl基因在TRAIL与8Gy照射联合时表达减弱。结论在体外实验中，乳腺癌MCF-7细胞株对TRAIL不敏感，但TRAIL与电离辐射照射联合后抗肿瘤作用增强，TRAIL可能是一种有临床应用潜能的新型抗肿瘤生物制剂。     

碳离子调强放射治疗复发性局部晚期鼻咽癌的近期疗效及不良反应

目的 分析局部复发性鼻咽癌患者再程调强碳离子放射治疗（IMCT）和调强X射线放射治疗（IMXT）后的近期疗效及不良反应。方法 收集本院2015年5月至9月收治的14例确诊为局部复发性鼻咽癌的患者,经再程IMCT治疗后,观察其治疗相关不良反应及近期疗效,并与2012年5月至2014年5月接受再程IMXT挽救性治疗的47例患者进行比较分析。复发肿瘤体积的IMCT和IMXT的处方剂量分别为50～60 GyE（2.0～2.5 GyE/次）和54～66 Gy/27～33次（2.0～2.1 Gy/次）。结果 两组患者在性别、年龄、初诊分期、初诊治疗策略、复发距首次IMXT时间间隔、复发T、N分期差异均无统计学意义（P>0.05）。两组患者放疗后3个月的完全缓解率（64.3%和78.7%）差异无统计学意义（P>0.05）,且在6个月内均无局部肿瘤进展,但IMXT组有2例死亡,其中1例死于鼻咽坏死大出血。IMCT组治疗中的急性中重度黏膜炎的发生率为0,明显低于IMXT组的31.9%（P<0.05）。IMXT治疗后6个月内黏膜坏死的发生率为29.8%,明显高于IMCT组的0（P<0.05）;IMXT组有2例（4.3%）伴症状的颞叶坏死,IMCT组无颞叶坏死;两组均无颅神经损伤发生。结论 同再程IMXT挽救治疗相比,复发性局部晚期鼻咽癌再程IMCT后近期疗效类似,且未出现2级或以上的近期不良反应,但IMCT的远期疗效尚需更长时间的观察。     

Concurrent use of aromatase inhibitors and hypofractionated radiation therapy

AIM: To retrospectively assess the acute and long-term toxicity using aromatase inhibitors (AI) therapy concurrently with hypofractionated radiotherapy (HFRT) in breast cancer patients. METHODS: From November 1999 to October 2007, 66 patients were treated with breast HFRT and concurrent AI. In 63 patients (95.5%), HFRT delivered a total dose of 32.5 Gy to the whole breast within 5 wk (five fractions, one fraction per week). Other fractionations were chosen in three patients for the patients’ personal convenience. A subsequent boost to the tumor bed was delivered in 35 patients (53.0%). Acute toxicities were scored according to the Common Toxicity Criteria for Adverse Events v3. Late toxicity was defined as any toxicity occurring more than 6 mo after completion of HFRT and was scored according to the Late Effects Normal Tissue Task Force-Subjective, Objective, Management and Analytic scale. RESULTS: At the end of the HFRT course, 19 patients (28.8%) had no irradiation-related toxicity. Acute grade 1-2 epithelitis was observed in 46 patients (69.7%). One grade 3 toxicity (1.5%) was observed. With a median follow-up of 34 mo (range: 12-94 mo), 31 patients (47%) had no toxicity, and 35 patients (53%) presented with grade 1-2 fibrosis. No grade 3 or greater delayed toxicity was observed. CONCLUSION: We found that AI was well tolerated when given concurrently with HFRT. All toxicities were mild to moderate, and no treatment disruption was necessary. Further prospective assessment is warranted.     

Offline adaptive radiation therapy in the treatment of prostate cancer: a case study

The purpose of this case study is to develop a method to account for the difference in the daily volumes in the bladder, rectum, and targets in prostate radiotherapy and to compare the predicted dose to the actual dose to these organs. Five patients, both prospectively and retrospectively, were selected from 2 different cancer centers, with a biopsy-confirmed diagnosis of prostate cancer. The patients' planning target volume (PTV) and organs at risk (OAR) were contoured on the computed tomography (CT) dataset using either Eclipse or Monaco treatment planning systems (TPSs). Cone-beam computed tomography (CBCT) scans were collected before each daily treatment and exported to MIM software for analysis. The automatically generated reports evaluated the organ volume changes, the actual dose received during a single fraction, and the projected dose to each organ at the completion of the treatment course via comparative cumulative dose-volume histograms (DVHs). Volume changes in the bladder and rectum can cause notable variations in the prescribed dose vs the actual dose received. MIM software was proven to have utility prospectively by tabulating daily dose and projecting final doses, potentially aiding physicians in decisions about the boost plans, thus making offline adaptive radiation therapy (ART) clinically manageable.     

不同布野方法对非小细胞肺癌调强放疗计划的影响

目的 探索非小细胞肺癌(NSCLC)调强放疗(IMRT)计划设计时不同的设野方法对于计划质量的影响。 方法 21例Ⅰ～Ⅲ期NSCLC患者进入本研究。IMRT采用固定野静态调强技术。每例患者采用不同的设野方法共设计3套调强计划,分别为:IMRT-7,使用等角度的7个射野,射野的入射角度分别为0°、51°、102°、153°、204°、255°、306°;IMRT-5,使用等角度的5个射野,射野的入射角度为0°、72°、144°、216°、288°;IMRT-5m,使用不等角度的5个射野,设野的方法为从前述IMRT-7的7个射野中去除2个野(若患者的病灶位于左肺,则去除角度为255°、306°的两野;若病灶位于右肺则去除角度为51°、102°的两野)。IMRT计划设计时正常肺剂量限制取之于同一患者实际治疗采用的3D-CRT计划肺V₅～V₆₀。IMRT开始取处方剂量为65 Gy,根据靶区和关键器官剂量要求按每2 Gy一阶梯进行递增或递减,直至获得最佳计划。结果 比较正常肺受量时发现,在V₅～V₂₅之间IMRT-5m的值较另两套计划均明显降低;V₃₀～V₄₀间3套计划相互间无明显差异;V₄₅～V₆₀间以IMRT-5计划最差;肺的平均剂量IMRT-5m最低。食管和脊髓的受量,靶区的适形性指数,以及治疗过程机器的总跳数3套计划间差异不明显。心脏V₄₀以IMRT-5m计划的值最低。两两比较时,IMRT-5较IMRT-7明显增加了靶区的异质性指数值,而其他比较无明显差异。相比于3D-CRT,IMRT-7、IMRT-5和IMRT-5m分别可提高靶区剂量(5.1±4.6)Gy、(3.1±5.3)Gy和(5.5±4.8)Gy。结论 对于NSCLC的IMRT计划设计,射野方向是重要因素,调整好设野的方向可以减少照射野数目保证甚至提高IMRT计划的质量。     

The impact of iterative reconstruction on image quality and radiation dose in thoracic and abdominal CT

Purpose

To compare the image quality and radiation dose between iterative reconstruction (IR) and standard filtered back projection (FBP) in CT of the chest and abdomen.

Materials and methods

Thoracic CT was performed in 50 patients (38 male, 12 female; mean age, 51 ± 23 yrs; range, 7–85 yrs) and abdominal CT was performed in 50 patients (36 male, 14 female; mean age, 62 ± 13 yrs; range, 20–85 yrs), using IR as well as FBP for image reconstruction. Image noise was quantitatively assessed measuring standard deviation of Hounsfield Units (HU) in defined regions of interest in subcutaneous tissue. Scan length and Computed Tomography Dose Index (CTDI) were documented. Scan length, image noise, and CTDI of both reconstruction techniques were compared by using paired tests according to the nature of variables (McNemar test or Student t test). Overall subjective image quality and subjective image noise were compared.

Results

There was no significant difference between the protocols in terms of mean scan length (p > 0.05). Image noise was statistically significantly higher with IR, although the difference was clinically insignificant (13.3 ± 3.0 HU and 13.6 ± 3.0 HU for thoracic CT and 11.5 ± 3.1 HU and 11.7 ± 3.0 HU for abdominal CT, p < 0.05). There was no significant difference in overall subjective image quality and subjective image noise. The radiation dose was significantly lower with IR. Volume-weighted CTDI decreased by 64% (6.2 ± 2.5 mGy versus 17.1 ± 9.5 mGy, p < 0.001) for thoracic CT and by 58% (7.8 ± 4.6 mGy versus 18.5 ± 8.6 mGy, p < 0.001) for abdominal CT.

Conclusions

Our study shows that in thoracic and abdominal CT with IR, there is no clinically significant impact on image quality, yet a significant radiation dose reduction compared to FBP.     

Combined transperineal implant and external beam radiation for the treatment of prostate cancer: a large patient cohort in the community setting

Purpose

Treatment of prostate cancer using higher doses of external beam radiation (EBRT) has been shown to improve results, but there are toxicity concerns with further dose escalation. A treatment option to safely increase total dose to the prostate includes combination therapy using EBRT and low-dose-rate transperineal brachytherapy seed implant. Our purpose was to report the results of combined modality therapy from a single institution in the community setting.

Methods and Materials

Retrospective review from single institution in the community setting. All patients were treated with a combination of EBRT followed by low-dose-rate brachytherapy seed placement.

Results

A total of 824 patients were analyzed with a median followup of 5.5 years, all censored patients had a minimum followup of 2 years. A total of 588 patients received hormone therapy before or concurrent with the radiation. Three hundred twenty-nine patients had low-risk disease, 300 patients had intermediate-risk disease, and 195 patients had high-risk disease. Five-year overall survivals were 86.1%, 85.0%, and 82.5% for low-, intermediate-, and high-risk patients. Five-year actuarial biochemical relapse-free survivals (bRFSs) were 85.4%, 83.2%, and 79.6% for low-, intermediate-, and high-risk patients. High-risk patients who received hormonal therapy had an improved bRFS vs. patients not receiving hormones.

Conclusions

Combination treatment using brachytherapy and EBRT is well tolerated, with acceptable overall survival and bRFS rates and should be considered a standard treatment option for patients. Hormones should be considered for high-risk patients.     

保乳术后固定野动态调强与容积调强放疗的剂量学比较

目的 比较早期乳腺癌保乳术后固定野动态调强与容积调强放疗治疗靶区和危及器官的剂量学差异.方法 20例左侧乳腺癌患者(均女性,24～75岁)保乳术后接受放疗,在同一患者CT影像上分别进行2野共面动态调强和容积调强(RapidArc)两种治疗计划设计.在剂量-体积直方图中读取两种计划的靶区剂量分布参数,心脏、双侧肺及对侧乳腺受照剂量和体积,对各参数的均数进行比较;并比较两者平均机器跳数和平均治疗时间的差异.结果 RapidArc较IMRT计划CTV V95%增加了0.65%(t=5.16,P=0.001),V105%下降了10.96%(t=-2.05,P=0.055),V110%下降了1.48%(t=-1.33,P=0.197).RapidArc计划的适形指数(CI)和均匀性指数(HI)均优于IMRT治疗计划,分别为0.88±0.02 vs 0.74±0.03(t=18.54,P＜0.001),1.11±0.01 Vs 1.12±0.02(t=-2.44,P=0.025).两种计划中左肺V20和Dmax比较差异无统计学意义,但在RapidArc计划中V10、V5、Dmix、Dmean明显增高,V5增高了接近30%.心脏V30和Dmax在两计划中无明显差异,而RapidArc计划的V10增加了18%,V5增加50%.RapidArc计划的右乳V5和右肺V5较IMRT分别增加了9.33%(t=9.31,P＜0.001)和3.04%(t=5.64,P＜0.001).RapidArc和IMRT平均机器跳数分别是608和437 MU(t=10.86,P＜0.001),平均治疗时间111.3和103.6 s(t=3.57,P=0.002).结论 早期乳腺癌保乳术后全乳腺RapidAre放疗与2野动态调强放疗相比,能明显改善靶区剂量分布均匀性.对于危及器官,高剂量区两种治疗计划之间无明显差异,低剂量区RapidArc的照射范围明显增加.与2野动态调强相比,RapidArc放疗机器跳数增加,治疗时间延长.

Abstract：

Objective To compare the dosimetric difference between volumetric are modulation with RapidArc and fixed field dynamic IMRT for breast cancer radiotherapy after breast-conserving surgery.Methods Twenty patients with early left-sided breast cancer received radiotherapy after breast-conserving surgery.After target definition,treatment planning was performed by RapidAre and two fixed fields dynamic IMRT respectively on the same CT scan.The target dose distribution,homogeneity of the breast,and the irradiation dose and volume for the lungs,heart,and eontralateral breast were read in the dosevolume histogram (DVH) and compared between RapidAre and IMRT.The treatment delivery time and monitor units were also compared.Results In comparison with the IMRT planning,the homogeneity of clinical target volume (CTV) ,the volume proportion of 95% prescribed dose (V95%) was significantly higher by 0.65% in RapidAre (t =5.16,P = 0.001) ,and the V105% and V110% were lower by 10.96% and 1.48 % respectively,however,without statistical significance (t =-2.05 ,P =0.055 and t =-1.33 ,P =0.197).The conformal index of planning target volume (PTV) by the Rap~dAre planning was (0.88±0.02),significantly higher than that by the IMRT planning [(0.74±0.03),t = 18.54,P < 0.001].The homogeneity index (HI) of PTV by the RapidArc planning was 1.11±0.01,significantly lower than that by the IMRT planning (1.12±0.02,t =-2.44,P =0.02).There were no significant differences in the maximum dose (Dmax) and V20 for the ipsilateral lung between the RapidArc and IMRT planning,but the values of V10,V5 ,Dmin and Dmean by RapidArc planning were all significantly higher than those by the IMRT planning (all P < 0.01).The values of max dose and V30 for the heart were similar by both techniques,but the values of V10 and V5 by the RapidArc planning were significantly higher (by 18% and 50% ,respectively).The V5 of the contralateral breast and lung by the RapidArc planning were increased by 9.33% and 3.04% respectively compared to the IMRT planning.The mean MU of the RapidArc was 608 MU,significantly higher than that by the IMRT planning (437 MU,t = 10.86,P < 0.001).The treatment time by the RapidArc planning was 111.3 s,significantly longer than that by IMRT planning (103.6 s,t = 3.57,P = 0.002).Conclusions The RapidArc planning improves the dose distribution of CTV and homogeneity of PTV for breast cancer radiotherapy after breast-conserving surgery.However,it significantly enlarges the volume of normal tissues irradiated in low dose areas,prolongs the treatment delivery time,and increases the MU value in comparison with IMRT.     

迭代模型重建技术在肺动脉“双低”成像中的应用研究

目的：探讨迭代模型重建(IMR)技术在肺动脉低剂量、低对比剂成像中的应用价值。方法对60例临床怀疑肺动脉栓塞(PE)患者行256层螺旋CT肺动脉成像,根据随机表法将患者随机分为实验组、对照组,每组30例。实验组原始数据分别采用滤波反投射(FBP)、IMR技术重建图像(A、B组),对照组原始数据采用 FBP 重建(C 组)。采用5分制方法评价肺动脉主干及其分支的图像质量,测量并计算肺动脉强化值(CT 值)、图像噪声值、图像信噪比(SNR)、对比噪声比(CNR),记录 CT 容积剂量指数(CTDIvol)、剂量长度乘积(DLP),计算有效剂量(ED)。比较 A组与 B组,B组与 C组肺动脉 CT值、图像噪声、SNR、CNR 及主观图像质量。结果实验组与对照组体质量指数(BMI)差异无统计学意义(P=0.096)。实验组CTDIvol、ED低于对照组(P<0.001)。A、B组肺动脉CT值差异无统计学意义(P=0.999),B组肺动脉CT值高于C组(P=0.005)。B组图像噪声明显低于A组(P<0.001),B组图像噪声高于C组(P<0.001)。B组 SNR、CNR高于 A组(P<0.001),B、C组 SNR、CNR差异无统计学意义(P=0.831,P=0.958)。B组图像可诊断率、优良率高于 A组(P<0.001),B、C 2组图像优良率差异无统计学意义(P=1.000)。结论肺动脉“双低”成像扫描模式联合更优化的迭代重建技术的应用,能够保证图像质量的同时大幅度降低患者辐射剂量及对比剂应用。