基于计算机图形处理与有限元仿真的前列腺穿刺变形模拟

摘 要：前列腺癌近距离放射治疗是有效治疗前列腺癌的一种微创治疗方法。然而在手术针向前列腺内部植入放射性粒子的过程中,前列腺和周围软组织器官的变形会导致粒子植入偏差。本文运用计算机图像处理与有限元仿真技术,使用患者术前的核磁图像,结合盆腔解剖学知识和三维重建技术,建立前列腺器官群有限元模型,并对粒子植入手术过程进行术前的有限元模拟计算,从而得到目标位置的变形量。有限元计算中的输入量均由实验数据结合有限元软件反求获得。结果表明：模型的穿刺变形量符合术中前列腺变形情况,周边组织器官均能提供有效约束。文章方法可以应用于术前穿刺轨迹规划、剂量规划和手术模拟训练机。     

基于核磁图像导航的前列腺针刺手术机器人

在对核磁共振图像(MRI)导航手术机器人设计需求进行分析的基础上,设计出一套可用于完成经会阴前列腺近距离粒子放射治疗手术的机器人系统.该系统具有5个自由度,通过核磁兼容气缸和超声波电机混合驱动,自主实现针体位姿调整和针刺操作.根据机器人系统动力学分析进行了驱动气缸选型.最后通过核磁兼容性实验和针刺精度实验,验证该机器人系统能够满足核磁兼容性要求,针刺精度为0.91mm.     

放射性药物~(188)Re标记DTPA的制备和在大鼠体内的分布

球囊导管内充盈β放射性核素防治经皮冠状动脉成形术(PTCA)后再狭窄是一种崭新的技术, 其中,188Re是一种常用的放射性核素。为了尽可能降低在万一球囊破裂的情况下高剂量放射性对人体的损害,利用二乙三胺五醋酸(DTPA)迅速从泌尿系统排出的特点,通过探索188Re标记DTPA的方法和条件,成功地制备了188Re-DTPA化合物,并研究出最佳的标记条件从而使标记产率达到90%以上。188Re-DTPA和188ReO4-在大鼠体内分布的研究结果显示,甲状腺和胃肠道的放射性水平188Re-DTPA组明显低于188ReO4-组,188Re-DTPA经肾脏排泄明显快于188ReO4-,用MIRDOSE 3.0软件估算体内重要脏器的吸收剂量同样也显示了这一结果。188Re-DTPA组和188ReO4-组甲状腺的吸收剂量分别为0.041 nGy/Bq和0.563 nGy/Bq,胃的吸收剂量分别为0.043 nGy/Bq和0.118 nGy/Bq。因此,实验结果认为在血管内照射治疗中188Re-DTPA明显优于188ReO4-。     

125I粒子组织间植入近距离治疗恶性肿瘤

采用¹²⁵I粒子植入法对20例恶性肿瘤患者的24个病灶进行治疗,以评价¹²⁵I粒子组织间植入恶性肿瘤的可行性及不良反应。术前制定肿瘤组织间三维立体定向放射治疗计划,在全麻剖腹直视下、全麻腹腔镜下或局麻CT、局麻彩色多普勒导向下经皮穿刺将¹²⁵I粒子植入恶性肿瘤病灶内。20例患者¹²⁵I粒子植入均顺利完成,术中及术后1周观察粒子在病灶内的分布基本与计划相符合,未观察到粒子迁移;术中及术后不良反应较为轻微且易于处理;多数患者临床症状得到不同程度的缓解,血清肿瘤标志物水平呈现不同程度的下降; 病情完全缓解（CR）20.00%（4/20例）, 部分缓解（PR）35.00%（7/20例）, 稳定（SD）30.00%（6/20例）,进展（PD）15.00%（3/20例）,总有效率（CR+PR）55.00%（11/20例）。以上结果表明,¹²⁵I粒子组织间植入近距离内放射治疗恶性肿瘤施术方便、安全有效,具有较高的临床价值,值得进一步推广及深入研究。     

三维适形放疗配合腔内后装治疗宫颈癌的临床研究

Objective: The aim of our study was to evaluate the outcome and complications of cervical cancer patients undergoing conventional intracavitary brachytherapy (ICBT) treated with 3D-conformal radiotherapy (3DCRT). Methods: Sixty cervical cancer patients were divided randomly into the conformal group and the conventional group. Thirty patients treated with 3D-conformal radiotherapy in the 3DCRT group, when the whole pelvic received DT 40 Gy, a planning CT scan of each patient was obtained and the second 3DCRT therapy plan was taken. Then, continued to irradiate to 50 Gy. At last, 3DCRT was boosted at local involved volumes to the total close of 60 Gy. When 3DCRT was combined with intracavitary brachytherapy, the dose of brachytherapy to point A was 30 Gy/5 fractions. In the conventional group, after a total tumor dose of 40 Gy was delivered by the whole pelvic irradiation, the four-field technique was used to irradiate the total pelvic and regional nodes (median close of 10 Gy), and the involved volumes were boosted to 60 Gy and the dose of brachytherapy to point A was 30 Gy-36 Gy/5-6 fractions. Moreover, both groups were combined with intracavitary brachytherapy respectively. Results: The 1, 2, 3-year survival rates for the 3DCRT group and the conventional group were 96.7%, 93.3%, 90.0% and 86.6%, 76.7%,70% respectively (P = 0.04, P = 0.02 and P = 0.02). There was a statistically significant difference between the two groups.Compared to the two groups each other in toxic effects, except for the Ⅰ-Ⅱ grade rectal and bladder reaction and pelvic fibrosis which was lower in the 3DCRT group (P = 0. 007, P = 0. 006 and P = 0. 015), the side effects were similar and well tolerated in two groups. Conclusion: The all-course 3DCRT combined with intracavitary brachytherapy can be considered as an effective and feasible approach to cervical cancer and may significantly improve the survival rate and reduce the late toxicity. This new rote for 3DCRT merits need further evaluation with large patient numbers and longer follows up.     

用蒙特卡罗方法确定81-02型198Au短程治疗源剂量计算参数

针对81-02型¹⁹⁸Au短程治疗源的临床应用，用蒙特卡罗方法计算了在一半径为30cm的理论球体模型中，AAPMTG43U1所推荐剂量计算参数的数值，包括剂量率常数、径向剂量函数和各向异性函数。所得单个81-02型¹⁹⁸Au短程治疗源的剂量率常数为1.113 cGy·h^-1·U^-1，与Dauffy等的理论计算值和TLD实测值分别相差0.18%和1.62％。在源中垂轴0.1～10.0cm距离范围内计算径向剂量函数的数值，在角度0°～90°（10°间隔）、距离0.5～9.0cm（1cm间隔）范围内计算各向异性函数的数值，最后对径向剂量函数和各向异性函数进行拟合，得到实用性较强的经验公式。     

手动式电磁定位及图像导航的短径癌症放射治疗系统

提出一个用于高剂量短径癌症放射治疗的手动式电磁定们及图像导航系统，该系统主要由4个模块组成：预处理、术前规划、术内导航和术后计划，它们分别对应高剂量短径癌症放射治疗的4个流程：在术前规划阶段，用户可交互地设计探针放置位置以及三维重建病灶轮廓；在手术进行过程中，六自由度的电磁式定位技术实时而精确地跟踪探针位置，高质量的可视化技术指引医生完成手术探针放置任务；手术探针全部放置完毕后，术后计划模板计算剂量分布并利用后装机设备进行放射治疗。初步实验表明，计算机辅助的探针定位比手工定位精度提高2-3倍，手术时间减少5倍以上，同时也减轻了病人所承受的放射剂量。     

Preliminary Research for Mutual Dose Perturbation Influence of 125I Brachytherapy Source

For two arrangement modes of two ¹²⁵I brachytheray sources, a homo-longitudinal axis and a homotransverse axis, the sum of dose distributions caused by each single source and actual dose distribution of the two coexisting sources are calculated separately in a clinically interested area by Monte Carlo simulation. Comparisons between them are used to evaluate the mutual dose perturbation influence. The result shows, for the homo-longitudinal axis arrangement, obvious perturbation can be observed along the longitudinal direction when the distances between sources' centers, L, are 0.5 cm and 1.0 cm, up to 11:7 ± 0:4% and 4:8 ± 0:2%, respectively, but, can be negligible for the distance exceeding 2.0 cm. For the homo- transverse axis arrangement, the range of dose perturbation depends on the source length and distances between sources' centers, and an influence extent is greater than the former, e.g., 27:2 ± 1:1%, 15:4 ± 0:6%, and 7:0 ± 0:3% maximum for L = 0:5 cm, 1.0 cm, and 2.0 cm, respectively. As for dose perturbation induced by the source leaning which happened in actual implant sometimes, the result indicates a dose fluctuation became more acute with obliquity increasing. The maximum dose increasing, 54:5 ± 2:1% and 199:7 ± 7:8%, and the maximum dose decreasing, 42:6 ± 1:7% and 64:9 ± 2:6%, could be observed for 10° and 30° obliquity with L = 1:0 cm for the two arrangement modes respectively.     

β粒子腋臭治疗仪的研制

研制了一种专门用于治疗腋臭的新型近距放疗仪,即β粒子腋臭治疗仪,又称β粒子腋臭敷贴器。该治疗仪由照射器、护持器、屏蔽罩、升降器、控制器和治疗车组成,利用设置在照射器内的90Sr/90 Yβ放射源对患者腋窝下的大汗腺实施全覆盖敷贴治疗,达到消除腋臭的目的。初步临床试验表明,无论是直接进行大汗腺照射,还是术后残留大汗腺的辅助照射均取得了确切疗效。该治疗仪为腋臭患者提供了又一种非手术、无痛苦、无创伤的治疗手段,且具有安全、有效、简便和操作自动化等特点。     

高剂量率近距离192Ir治疗源的井型电离室仪器的校准

针对后装治疗用192 IF放射源的参考空气比释动能率的量值急需进行溯源.参考国际通例,由指型电离室(PTW-30013)在60Coγ射线和250 kV X射线下的空气比释动能校准因子推导得出192Ir γ射线的空气比释动能校准因子,从而测定192Ir放射源参考空气比释动能率标准值,进而完成对井型电离室的参考空气比释动能...