A direct voxel tracking method for four-dimensional Monte Carlo dose calculations in deforming anatomy

In this work we present a method of calculating dose in deforming anatomy where the position and shape of each dose voxel is tracked as the anatomy changes. The EGSnrc/DOSXYZnrc Monte Carlo code was modified to calculate dose in voxels that are deformed according to deformation vectors obtained from a nonlinear image registration algorithm. The defDOSXYZ code was validated by consistency checks and by comparing calculations against DOSXYZnrc calculations. Calculations in deforming phantoms were compared with a dose remapping method employing trilinear interpolation. Dose calculations with the deforming voxels agree with DOSXYZnrc calculations within 1%. In simple deforming rectangular phantoms the trilinear dose remapping method was found to underestimate the dose by up to 29% for a 1.0 cm voxel size within the field, with larger discrepancies in regions of steep dose gradients. The agreement between the two calculation methods improved with smaller voxel size and deformation magnitude. A comparison of dose remapping from Inhale to Exhale in an anatomical breathing phantom demonstrated that dose deformations are underestimated by up to 16% in the penumbra and 8% near the surface with trilinear interpolation.     

宫颈癌放疗中计算网格尺寸对物理剂量和生物剂量的影响

目的:定量分析剂量计算网格尺寸（DCGS）对宫颈癌放疗中物理剂量和生物剂量的影响。方法:选取Pinnacle3治疗计划系统中宫颈癌的治疗方案12例,取默认值DCGS=4.0 mm的计算网格,优化调整宫颈癌治疗方案,再改变DCGS（1.0～7.0 mm）,重新计算靶区和危及器官（OAR）的剂量,探讨靶区和OAR的物理剂量和生物剂量随DCGS的变化情况。结果:靶区和OAR的物理剂量随DCGS的变大而减小,在体积剂量直方图上表现出曲线整体向低剂量区平移。除左右股骨头外,靶区的肿瘤控制概率（TCP）和OAR的正常组织并发症概率（NTCP）也随DCGS增大而缓慢降低。PGTVnd的TCP下降率约为0.7%/mm,PTV的TCP下降率约为0.6%/mm,而膀胱和直肠的NTCP下降速度相对较快,膀胱NTCP下降率最大值为15.0%,直肠NTCP下降率最大值为13.5%。结论:宫颈癌放疗中物理剂量和生物剂量随DCGS变大而减少,靶区和OAR的物理剂量在体积剂量直方图上表现出整体向低剂量区平移,这种变化趋势会诱导研究者低估靶区的TCP及OAR的NTCP。     

The influence of grid size on accuracy in radiotherapy dose plotting

The recent article by Niemierko and Goitein [Med. Phys. 16, 239-247 (1989)] illustrates well the errors which are occurring in plotting isodose lines. We wish to augment their analysis with similar work done at Cardiff a few years ago; to indicate some practical treatment outcomes they have omitted; to propose even more stringent requirements of the grid size used; and thus to further alert users and software manufacturers to this problem.     

Taxol dose intensification and its clinical implications.

Taxol is the most exciting new anticancer agent developed in the past two decades. Of great interest is its level of activity in ovarian cancer, as well as substantial activity in breast cancer, nonsmall-cell lung cancer, melanoma, and other malignancies. Recent studies suggest that when taxol is administered in a fashion to increase milligram dosage per unit time (mg/m2/week), the response rate in patients with ovarian cancer is markedly increased. This article reviews studies that suggest taxol dose intensity is important in the treatment of patients with ovarian cancer.     

颞骨的断面解剖学研究及其临床意义

目的：进一步明确颞骨的断面形态和各结构的解剖关系，为影像诊断和手术治疗提供解剖学依据。方法：将6例成人头颅标本制备成层厚0．5mm的耳颞部火棉胶横断切片，逐一观测。结果：以HRCT为参考，选取11个典型层面：①上半规管层面；②上鼓室层面；③外半规管层面；④锤砧关节层面；⑤内耳道底下部层面；⑥前庭窗层面；⑦匙突层面；⑧后鼓室层面；⑨蜗窗层面；⑩鼓膜脐层面；(11)咽鼓管层面。对层面内主要结构的断面形态及其毗邻关系进行了描述。结论：颞骨火棉胶薄切片能很好地显示颞骨的解剖结构及其毗邻关系，对该区的影像诊断和手术治疗有重要的参考价值。     

Surgical anatomy of the pudendal nerve and its clinical implications

A study of the surgical anatomy of the pudendal nerve (PN) was performed in 13 female and 7 male cadavers. The knowledge of the precise anatomy and anomalies of this important nerve would help in better localization of the nerve and its roots and branches for neurostimulation or for pudendal canal decompression in pudendal canal syndrome. Two routes were used in the dissection: gluteal and perineal. The PN was identified and its course was followed from its roots to its termination. The PN was composed of three roots derived from the 2nd, 3rd, and 4th anterior sacral rami (S 2,3,4). The roots received a contribution from S 1 in five cadavers and from S 5 in one. The three roots formed two cords. The first root continued as the upper cord while the second and third root fused together producing the lower cord. The PN was formed by union of the two cords a short distance proximal to the sacrospinous ligament, and then crossed the back of the ligament. In no specimen did the nerve cross the ischial spine. The inferior rectal nerve arose from the PN in the pudendal canal in 18 cadavers. In two cases it came out proximal to the canal; this would spare the two subjects the anorectal manifestations of the pudendal canal syndrome. As the PN crossed the back of the sacrospinous ligament, it gave origin to a branch that supplied the levator ani muscle. This branch was only found in male cadavers and we call it “accessory rectal nerve”; the levator ani muscle in such cadavers was doubly innervated on its perineal aspect. © 1995 WiIey-Liss, Inc.     

The arterial anatomy of the Achilles tendon: Anatomical study and clinical implications

The Achilles tendon is the most frequently ruptured tendon in the lower limb and accounts for almost 20% of all large tendon injuries. Despite numerous published studies describing its blood supply, there has been no uniformity in describing its topography. The current study comprises a detailed anatomical study of both the intrinsic and extrinsic arterial supply of the Achilles tendon, providing the detail sought from studies calling for improved planning of surgical procedures where damage to the vascularity of the Achilles tendon is likely. A dissection, microdissection, histological, and angiographic study was undertaken on 20 cadaveric lower limbs from 16 fresh and four embalmed cadavers. The Achilles tendon is supplied by two arteries, the posterior tibial and peroneal arteries. Three vascular territories were identified, with the midsection supplied by the peroneal artery, and the proximal and distal sections supplied by the posterior tibial artery. The midsection of the Achilles tendon was markedly more hypovascular that the rest of the tendon. The Achilles tendon is at highest risk of rupture and surgical complications at its midsection. Individuals with particularly poor supply of the midsection may be at increased risk of tendon rupture, and approaches to the tendon operatively should consider the route of supply by the peroneal artery to this susceptible part of the tendon. Clin. Anat. 22:377–385, 2009. © 2009 Wiley‐Liss, Inc.     

Variations in the anatomy of the celiac trunk: A systematic review and clinical implications

The normal pattern of the celiac trunk (CT) implies its bifurcation to three branches, the common hepatic, the splenic and the left gastric artery. According to the available literature the CT presents several anatomical variations. The purpose of our study is to investigate the different types of these variations, the corresponding incidences and the probable influence of genetic factors, as they are presented in the existing literature. Four databases were searched for eligible articles for the period up to January 2013 and a total of 36 studies were collected. The CT was trifurcated into the three basic branches in the 89.42% (10,906/12,196) of the cases. Bifurcation of the CT occurred in the 7.40% of the pooled samples (903/12,196). Absence of the CT was the rarest variation with a percentage of 0.38% (46/12,196), hepatosplenomesenteric trunk was found in 49 out of the 12,196 cases (0.40%) and the celiacomesenteric trunk presented an incidence of 0.76% (93/12,196). Other variations of the CT were detected in the 1.64% of the pooled cases (199/12,196). The 14.9% of the cases in the cadaveric series (489/3278 specimens), the 10.5% in the imaging series (675/6501 specimens) and the 4.6% (104/2261) in the liver transplantation series presented variations. These differences are statistically significant (p < 0.001). The Japanese and Korean populations presented more variations in the CT than Caucasians (p < 0.05 and p < 0.001). Negro, colored and black populations presented more variations of the CT than Indian ones (p > 0.05).Using those data, a novel classification of CT variations is proposed.     

The anatomy and variations of the internal thoracic (internal mammary) artery and implications in autologous breast reconstruction: clinical anatomical study and literature review

Background  

The internal thoracic (IT) vessels (otherwise known as the thoracica interna or internal mammary vessels) are widely used as recipient vessels in autologous breast reconstruction. Despite this, normal and pathological variations in IT artery architecture have been described, and these have the potential to complicate dissection and the selection of suitable vessels.     

A feasible method for clinical delivery verification and dose reconstruction in tomotherapy

Delivery verification is the process in which the energy fluence delivered during a treatment is verified. This verified energy fluence can be used in conjunction with an image in the treatment position to reconstruct the full three-dimensional dose deposited. A method for delivery verification that utilizes a measured database of detector signal is described in this work. This database is a function of two parameters, radiological path-length and detector-to-phantom distance, both of which are computed from a CT image taken at the time of delivery. Such a database was generated and used to perform delivery verification and dose reconstruction. Two experiments were conducted: a simulated prostate delivery on an inhomogeneous abdominal phantom, and a nasopharyngeal delivery on a dog cadaver. For both cases, it was found that the verified fluence and dose results using the database approach agreed very well with those using previously developed and proven techniques. Delivery verification with a measured database and CT image at the time of treatment is an accurate procedure for tomotherapy. The database eliminates the need for any patient-specific, pre- or post-treatment measurements. Moreover, such an approach creates an opportunity for accurate, real-time delivery verification and dose reconstruction given fast image reconstruction and dose computation tools.     

腰骶丛三角工作区的应用解剖及临床意义

BACKGROUND: Conception of three-dimensional reconstruction of the lumbosacal plexus is confused, and actual physical anatomy is needed to confirm its range and area thus providing guidence for clinical pratice.     

Variations in the anatomy of the thyroid gland: clinical implications of a cadaver study

Surgical removal of the thyroid gland is associated with risk of damage to the parathyroid glands, external branch of superior laryngeal nerves, inferior laryngeal nerves, and haematoma due to vascular damage and the chance of residual thyroid tissue being left in case of cancer and Graves’ disease. The present study was designed to report the prevalence of anatomical variations and developmental anomalies of the thyroid gland that will hopefully help to minimise the aforementioned complications related to thyroid surgery. A total of 52 male and 18 female properly embalmed cadavers were dissected. The thyroid gland was examined for the presence of the pyramidal lobe, levator glandulae thyroideae and partial or complete absence of isthmus. Length, greatest transverse and anteroposterior extent of both the right and left lobe of the gland was recorded. A pyramidal lobe was present in 43.9% male and 22.2% female cadavers and was more prevalent on the left side of the median plane. Levator glandulae thyroideae was present in 34.6% male and 27.8% female cadavers. Isthmus was absent in 9.6% male and 5.6% female cadavers. The average length, greatest transverse and anteroposterior extent of right lobe was 4.43, 2.54 and 1.69 cm, respectively, whereas for the left lobe it was 4.21, 2.63 and 1.7 cm, respectively. The nature of the specimens studied, and the region where the study is carried out, affect the different goitre zones, age, sex, and race of population studied, all of which can contribute to the anatomical variations of the thyroid gland found in different reports by various authors.     

CT图像和重组技术在骶椎临床影像解剖学研究中的应用

目的 观察骶椎的解剖形态及其与耻骨联合的位置关系,为骶椎正位X线摄影体位的优化设计提供解剖学依据。 方法 回顾性随机收集1000例患者骨盆腔CT影像,借助CT图像重组技术观测骶椎的解剖形态及其与耻骨联合的相对位置关系。 结果 骶椎均为前面凹陷、底朝上、尖向下后方走行,骶椎上下端中点连线M与人躯体长轴之间的夹角A均为锐角,耻骨联合位于骶椎的前正中偏下位置,其与骶椎下缘的连线N和躯体长轴垂线间夹角B>0 °（即耻骨联合上缘低于骶椎下缘的位置）占89.7%（897/1000);青少年组（14~45岁）角A为（35.86±6.88）°,明显低于中年组（46~69岁）（37.82±6.34）°和老年组（>69岁）（37.60±6.65）°（P<0.05）,青少年组角B为（10.27±7.02）°,明显高于中年组（8.88±7.23）°和老年组（7.83±6.93）°（P<0.05）,而中年组和老年组间差异均无统计学意义;男性角A（36.12±0.27）°和角B（6.27±0.25）°,均明显低于女性（38.03±0.33）°和（12.79±0.33）°（P<0.05）。 结论 CT图像重组技术可用于观察和分析骶椎的解剖形态及其与耻骨联合的位置关系,不同年龄段和不同性别者骶椎与耻骨联合的相对位置情况差异显著,可为骶椎正位X线摄影检查体位的优化设计提供可靠的解剖学依据。     

数字化前臂穿支皮瓣模型构建与解剖学研究

目的　利用计算机三维重建技术构建前臂数字化模型,探讨前臂动脉穿支特点,虚拟仿真临床个性化皮瓣设计。 方法　选用新鲜男尸体无器质性损伤前臂标本4只,常温下灌注显影剂,经CT扫描后,将数据导入医学图像处理软件Mimics13.1中,分别对骨骼、血管及软组织进行三维构建。测量前臂穿支血管数目、蒂长、管径,距尺、桡骨茎突距离,为穿支皮瓣切取提供依据。根据穿支血管支配区域,对图像进行多次分割,构建数字化穿支皮瓣。 结果　数字化前臂三维构建的图像仿真高,可立体显示前臂各穿支血管及其穿支皮瓣。桡动脉、尺动脉、骨间后动脉穿支血管数是12～17、10～15、5～11支,与实体解剖学数据基本一致。 结论　通过构建数字化前臂模型,测量数据表明各标本动脉起源、行程及其穿支较恒定,可根据尺桡动脉及骨间后动脉穿支血管的分布情况,设计皮瓣的范围,对临床穿支皮瓣的切取具有较重要的意义。     

Coracoid process anatomy: implications in radiographic imaging and surgery

The coracoid process forms an important part of scapular-glenoid construct and is involved in many surgical procedures on the glenohumeral joint. The unique three-dimensional orientation of each coracoid pillar makes radiographic imaging difficult. Congenital variations and minimal traumatic/iatrogenic changes in this orientation can predispose to subcoracoid impingement. We performed a quantitative and statistical analysis of the osseous anatomy of the coracoid process in 101 scapulae; the purpose was to determine the anatomical variations and gender-specific differences in the length, breadth, thickness, vertical and horizontal projections, and triplane angulations of each individual coracoid pillar. All parameters were measured in reference to the glenoid plane to ensure surgical and radiological applicability. The mean dimensions of the inferior coracoid pillar were 31.1 x 16.6 x 9.9 mm and that of the superior coracoid pillar were 41.7 x 14.2 x 8.4 mm (medial)/6.6 mm (lateral). The mean maximal harvestable coracoid length measured 19.0 mm. The mean angular orientation of the inferior coracoid pillar, with reference to the glenoid, measured 51.2 degrees (axial), 126.1 degrees (sagittal), and 134.6 degrees (coronal), and that of the superior coracoid pillar measured 146.1 degrees (axial) with an interpillar angulation of 84.9 degrees (axial). A statistically significant gender difference (P < 0.05) was found in the lengths, breadths, and projections of each coracoid pillar. We used data from this study to devise two new radiographic views (for imaging individual coracoid pillars), to calculate dimensions and orientation of internal fixation/prosthetic hardware during surgery, and conceptualize a geometric model to explain the role of measured parameters in coracoid impingement syndrome.     

髋臼前柱骨折重建钢板内固定的临床解剖学

目的：研究髋臼前柱切面解剖特点,为安全放置重建钢板治疗髋臼前柱骨折提供依据。方法：采用正常国人骨盆标本15具,以骨盆界线及相关骨性标志为参考予髋臼前柱切片,结合解剖标志对各切面进行观测。结果：前柱从闭孔沟到髂前上棘横切面为变化的近似三角形,此段距界线10 mm点到髋臼的切线与前柱上面的夹角由(72.6±4.8)°变小为(44.6±4.7)°,再增大为(82.4±3.2)°,髂耻隆起处切线角度最小。 结论：从闭孔沟到髂前上棘髋臼前柱应分段处理,对切面按变化的三角形处理,可帮助判断安全钉道的角度及深度。     

Dose and dose rate effects of whole-body proton-irradiation on lymphocyte blastogenesis and hematological variables: part II.

The goal of part II of this study was to evaluate functional characteristics of leukocytes and circulating blood cell parameters after whole-body proton irradiation at varying doses and at low- and high-dose-rates (LDR and HDR, respectively). C57BL/6 mice (n=51) were irradiated and euthanized at 4 days post-exposure for assay. Significant radiation dose- (but not dose-rate-) dependent decreases were observed in splenocyte responses to T and B cell mitogens when compared to sham-irradiated controls (P<0.001). Spontaneous blastogenesis, also significantly dose-dependent, was increased in both blood and spleen (P<0.001). Red blood cell counts, hemoglobin concentration, and hematocrit were decreased in a dose-dependent manner (P<0.05), whereas thrombocyte numbers were only slightly affected. Comparison of proton- and gamma-irradiated groups (both receiving 3 Gy at HDR) showed a higher level of spontaneous blastogenesis in blood leukocytes and a lower splenocyte response to concanavalin A following proton irradiation (P<0.05). There were no dose rate effects. Collectively, the data demonstrate that the measurements in blood and spleen were largely dependent upon the total dose of proton radiation and that an 80-fold difference in the dose rate was not a significant factor. A difference, however, was found between protons and gamma-rays in the degree of change induced in some of the measurements.