Craniocaudal Direction Research Articles

Effect of image quality on correlation modeling error using a fiducial marker in a gimbaled linear accelerator.

The purpose of this study was to investigate the effect of image quality under various imaging parameters (60, 70, 80, 90, 100, 110, and 120kV at 200mA and 10ms/63, 80, 100, 160, 200, 250, and 320mA at 120kV and 10ms) and the diameter of the fiducial marker (0.25, 0.50, 0.75, and 1.10mm) on the correlation modeling error for dynamic tumor tracking (DTT) in the Vero4DRT system. Each fiducial marker was inserted into the center of the 30×30×10cm3 water-equivalent phantom. A programmable respiratory motion table was used to simulate breathing-induced organ motion, with an amplitude of ±20mm and a breathing cycle of 4s. The correlation modeling error was calculated from the absolute difference between the detected and predicted target positions in the cranio-caudal direction. The image contrast of the fiducial marker was enhanced with increasing kV and mA. Increasing the diameter of the fiducial marker also enhanced the image contrast. Correlation-modeling error does not depend on the image quality and fiducial marker diameter. A lower kV setting did not generate a 4D model due to poor image contrast. All fiducial marker diameters were identified as good candidates for DTT in the Vero4DRT system.

Telovelar approach versus transvermian approach in management of fourth ventricular tumors

BackgroundThe relationships of the fourth ventricle to the cerebellar surfaces and the fissures through which the fourth ventricle is approached surgically are among the most complex in the brain. The area in and around the fourth ventricle may be affected by a variety of neoplasms. Some are unique to the fourth ventricle; others are also found in different locations. The two most common surgical approaches to the fourth ventricle are the transvermian and the telovelar approaches.The aim of this studyThe aim of this study is to compare the results of telovelar and transvermian approaches in the management of fourth ventricular tumors with regard to clinical outcome and extent of tumor excision.Patients and methodsThis study includes 40 patients presented at Ain Shams University Hospital and Nasser Institute with the diagnosis of fourth ventriclular tumors in a 4-year period between 2011 and 2015. Surgical treatment was done in all cases in form of (1) a CSF diversion for hydrocephalic patients through insertion of V-P shunt or EVD. (2) Completely randomly choosing an approach, 20 patients were operated through the transvermian approach (50% of all patients) and 20 patients were operated through the telovelar approach. Patients were examined clinically, radiologically, and functionally using the Karnofsky performance scale at the postoperative period, every 3 months for the first year, and then 6 months thereafter.ResultsTotal excision of the tumor was achieved in 27 patients (67.5% of all patients) and 15 patients (75% of 20 patients operated via telovelar approach).There were 13 patients (32.5%) with different postoperative complications, 6 patients underwent telovelar approach,1 case of superficial infection, 3 cases of bulbar palsy (15% of patients operated via telovelar approach), and 3 cases of cerebellar mutism (15% of patients operated via transvermian approach and 7.5% of all patients).ConclusionThe telovelar approach can give better exposure to the fourth ventricle in craniocaudal direction and lateral direction without splitting of the vermis. For lesions in the upper half, the ventricletelovelar approach can be used but we have to shift to the transvermian approach for complete resection. The transvermian approach has a higher risk of postoperative cerebellar mutism syndrome particularly in children.

Dynamic Changes of Cauda Equina Motion Before and After Decompressive Laminectomy for Lumbar Spinal Stenosis With Redundant Nerve Roots: Cauda Equina Activation Sign

Study Design:Cross-sectional observational study (consecutive case series).Objectives:The aim of this study was to define a criterion for achieving successful decompression of lumbar spinal stenosis (LSS) using intraoperative ultrasonography (IOUS) and to investigate the pathogenesis of redundant nerve roots (RNRs) based on the ultrasonographic findings.Methods:A total of 100 LSS patients (71 males, 29 females, mean age, 71 ± 8 years) with RNRs were enrolled as subjects in this study. IOUS was performed to evaluate pulsatile motion of the cauda equina (PMCE) just before and after decompressive laminectomy. To determine the decompression status of the cauda equina, the ultrasonographic findings were classified into 3 types on the basis of the presence or absence of PMCE: type 1, predecompression PMCE (−) to postdecompression PMCE (+); type 2, pre- and postdecompression PMCE (+); and type 3, pre- and postdecompression PMCE (−). The pathogenesis of RNRs was also investigated based on the ultrasonographic findings.Results:Around the stenosis, PMCE was almost always absent before decompression and appeared after decompression (type 1 in 94 patients, type 2 in 6, type 3 in 0). IOUS showed that, before decompression, the cauda equina was held at the stenosis and could not pulsate beyond the stenotic site, and after decompression, PMCE recovered in the craniocaudal direction, leading to the resolution of RNRs.Conclusions:The emergence of PMCE can be a sign of successful decompression for LSS. Ultrasonographic findings support the notion that disturbance of PMCE around the stenosis is a basic component of the pathogenesis of RNRs.

Surgical management of suprastomal tracheal collapse in children

ObjectiveSuprastomal collapse is a complication of pediatric tracheotomy with a potential impact on decannulation success. The aim of this study was to review the experience in the management of pediatric suprastomal collapse in a tertiary-care center, detailing the surgical technique employed. MethodsThis study included 12 tracheotomised children with the diagnosis of suprastomal collapse in the last 5 years. All patients of the study underwent surgical intervention to manage suprastomal collapse to achieve tracheotomy decannulation. The surgical procedure entailed dissection of the pre-existing tracheotomy tract down to the trachea, then excision of the tract flush with the anterior tracheal wall. The tracheal opening was closed transversely with 3–4 interrupted absorbable sutures placed in craniocaudal direction. ResultsAt the end of treatment all patients were decannulated successfully. No intraoperative complications were reported. Minor postoperative complications were reported in 3 children in the form of mild surgical emphysema (n = 2) and wound infection (n = 1). Those patients were successfully managed conservatively. ConclusionThis technique is a simple and effective procedure enabling immediate decannulation with very low morbidity. In a long term follow up period, no recurrence has been reported and all patients returned to their usual quality of life.

Massive splenic calcification in amyloidosis with normal labs and physical exam.

A 64-year-old male with medical history of hypertension, type II diabetes, coronary artery disease, and AL amyloidosis involving the heart, kidney and liver was admitted for decompensated heart failure, requiring Intra-Aortic Balloon Pump (IABP) and inotropic support. The patient was listed for heart transplant, but later developed cardiac arrest and required Veno-Arterial Extracorporeal Membrane Oxygenation (VA ECMO) treatment. Abdominal X-ray was obtained to confirm the position of feeding tube which showed massive intra-peritoneal calcification (A). CT abdomen was obtained, and he was found to have extensive splenic calcification measures 8.9 x 7.1cm in cross-section and it spans 8.9 cm in craniocaudal direction (B). Spleen was impalpable on physical exam. Before the cardiac arrest, patient's renal function was at baseline, with the remaining of the basic metabolic panel normal. Hepatic function panel was significant for mild elevation in alkaline phosphatase and alanine aminotransaminases. All other laboratory work including coagulation and iron studies were normal. Nonetheless, patient's condition deteriorated over the course and he expired. Amyloid fibrils have an affinity to calcium and can result in calcific deposition in organs. Literature review showed that in amyloidosis, splenic calcification occurs in conjunction with other organs calcification especially liver. Thus this patient's case highlights the unique presentation of massive splenic calcification without any other organ calcification with relatively normal laboratory and physical examination except findings consistent with his heart failure diagnosis.

12 Study of the anatomy position reproducibility during deep inspiration breath hold

Introduction Mobile tumors radiotherapy (breast, lung, abdomen) is face to major discrepancies coming from respiratory movements. This is why innovative techniques have been developed with the objective of gating the beams. Deep Inspiration Breath Hold (DIBH) technique allows to control the respiratory movements with the help of a spirometer and visual feedback. The aim of this study is to estimate the anatomy position reproducibility during DIBH with images acquired during the treatment, for three sites: breast, lung, abdomen. Methods The files analyzed concerned patients benefiting from DIBH with the SDX/Dyn’R spirometer. The analyzes were performed on images acquired with the MV and kV imagers for the planar and CBCT modalities. Breast: Distance evaluations between the DRR and the weekly EPID image for 15 patients. Due to a lack of reliable bony marks in the breast EPID image, we used the sub-mammary fold position and some crossing between two ribs. Lung: Retrospective analysis of two thoracic CT acquired before the treatment and at 2/3 of the sessions for 30 patients. The measurements concerned: lung volume, diaphragm, heart, tracheal carina positions and patient thickness at the thoracic and abdominal levels. The daily kV images enabled to measure the diaphragm and the sternum positions with regard to the spine (10 patients). Abdomen: Estimation of the diaphragm and the sternum positions, with kV images for 15 patients. The CBCT acquisition allowed studying the reproducibility, between two apneas, of the soft tissues positions and specifically the displacement of the kidneys and biliary prosthesis (10 patients). Results Results are given in Fig. 1. The DIBH technique for a mammary tumor does not reveal important variation of the heart position with regard to the rib cage: mean 3.6 mm (±2.6 mm) perpendicularly to the internal tangential beam. Concerning the thorax, the biggest movements are situated at the diaphragmatic and abdominal levels in cranio-caudal direction, respectively mean 5.7 mm (±4.0 mm) and 7.3 mm (±5.9 mm). For the abdominal region (gastric, hepatic, pancreatic tumor), kidneys and diaphragm are subjected to the biggest gaps: mean 6.3 mm (±5.6 mm) and 5.8 mm (±4.0 mm) in cranio-caudal direction. Download : Download high-res image (141KB) Download : Download full-size image Conclusion The Deep Inspiration Breath Hold method offers anatomical immobilization. We have studied the reproducibility of the organs and tissues positions during several apneas. The results are on average infra-centimetric with more pronounced variations in the abdominal area affected by variations of the digestive filling. These evaluations establish the minimum margins to be taken into account to build a PTV volume.

18 SBRT for peripheral lung tumors with linac arctherapy technique: More accurate, fast and safe

Introduction Over the past decade, there have been significant changes in the dosimetric management of peripheral lung tumor treatments with stereotactic radiotherapy. Historically developed on linear accelerators using additional collimators, the treatments are now performed on dedicated accelerators (CyberKnife, Vero, STX TrueBeam, Versa HD for example) with dedicated equipment (positioning imagery, breathing control, contention) and dedicated beam types (Flattening Filter Free). First performed in 3D conformal radiotherapy (3D-CRT), treatments are now indicated in intensity-modulated rotational radiotherapy (VMAT) [1] . Methods This prospective study was conducted on 30 patients with peripheral lung tumor treated by SBRT. The objective was to assess, through metrics (NC, CI, HI, Dmin PTV , and volumes of isodoses 5Gy, 10Gy, D50% and. Dpresc. [2] , the possibility to improve dose distribution and decrease delivery time of SBRT with VMAT and no longer in 3D – CRT. The planning has been conducted with the RayStation v6 TPS. The scheme of radiotherapy was 48Gy in 6 fractions and the average volume of PTV was 18.3 ± 11.8cc. For each patient, the ITV was determined and the PTV achieved by applying margins of 5mm in the cranio-caudal direction and 3mm elsewhere. Two treatment plans were made: one 3D-CRT in 6MV-FFF and the other in VMAT 6MV-FFF with limitation of the movement of the blades. The optimization of the treatment plans was carried out so that 99% of the PTV volume is covered by the prescription isodose with for the 3D-CRT a collimator opening limit of 5 mm and a limit of prescription at Isocenter point of 80%. The metrics of the 30 patients were recorded and compared by a Wilcoxon test. The treatment delivery time was measured for the 3D-CRT technique and the estimate time was provided by the TPS for the VMAT. Results The results are presented in Table 1 and Fig. 1. For almost all of the patients, the coverage of 99% of the PTV was met. Our technique allows to get a better number of conformity (p 0.001) as well as volumes of isodose 10Gy, D50% and Dpresc. smaller (p 0.001). The duration of treatment sessions has been reduced from 150 to 47 sec. Conclusions The limitation of leafs movement, use of partial arcs with only photons flow variation during arc delivery achieve more consistent coverage and lower lung irradiation without interplay effect during irradiation sessions. This technique is now performed in routine.

Modelling the effects of lung cancer motion due to respiration

Abstract Background and objectives: To justify the concept of validating conformal versus intensity-modulated approach in the treatment of non-small cell lung cancer (NSCLC). Materials and methods: For 10 patients representative of the spectrum of tumour sizes and locations, two plans were prepared: one with three-dimensional conformal radiation therapy (3DCRT) technique and the other with intensity-modulated radiation therapy (IMRT) technique. Preliminary measurements were performed in static conditions. For each of the field angles considered, the motion kernel was generated to simulate tumour motion trajectories, with the largest amplitude in the cranio-caudal direction of 4, 6, and 8 mm. The measurement results determined the agreement between the planned and measured doses. Results: No statistically significant differences were found between the motion patterns, with the smallest amplitudes for clinical target volume in 3DCRT. For IMRT, the significant differences between 0 mm vs. 6 mm and 0 mm vs. 8 mm amplitudes were found. The motion impact on delivered vs. planned doses had less effect on the oesophagus in 3DCRT compared to that in IMRT. The observed differences were comparable for the heart. Interpretation and conclusions: For maximal amplitudes below 4 mm, the disagreement between planned and delivered doses can be neglected. However, the amplitudes above 5 mm and 7 mm lead to significant changes in IMRT and 3DCRT dose distribution, respectively.

Evaluation of Dynamic Tumor-tracking Intensity-modulated Radiotherapy for Locally Advanced Pancreatic Cancer

Intensity-modulated radiotherapy (IMRT) is now regarded as an important treatment option for patients with locally advanced pancreatic cancer (LAPC). To reduce the underlying tumor motions and dosimetric errors during IMRT as well as the burden of respiratory management for patients, we started to apply a new treatment platform of the dynamic tumor dynamic tumor-tracking intensity-modulated radiotherapy (DTT-IMRT) using the gimbaled linac, which can swing IMRT toward the real-time tumor position under patients’ voluntary breathing. Between June 2013 and March 2015, ten patients were treated, and the tumor-tracking accuracy and the practical benefits were evaluated. The mean PTV size in DTT-IMRT was 18% smaller than a conventional ITV-based PTV. The root-mean-squared errors between the predicted and the detected tumor positions were 1.3, 1.2, and 1.5 mm in left-right, anterior-posterior, and cranio-caudal directions, respectively. The mean in-room time was 24.5 min. This high-accuracy of tumor-tracking with reasonable treatment time are promising and beneficial to patients with LAPC.

Feasibility of intensity-modulated radiotherapy to treat gastric cancer.

To present a proposed gastric cancer intensity-modulated radiotherapy (IMRT) treatment planning protocol for an institution that have not introduced volumetric modulated arc therapy in clinical practice. A secondary aim was to determine the impact of 2DkV set-up corrections on target coverage and organ at risk (OAR). Twenty consecutive patients were treated with a specially-designed non-coplanar 7-field IMRT technique. The isocenter-shift method was used to estimate the impact of 2DkV-based set-up corrections on the original base plan (BP) coverage. An alternative plan was simulated (SP) by taking into account isocenter shifts. The SP and BP were compared using dose-volume histogram (DVH) plots calculated for the internal target volume (ITV) and OARs. Both plans delivered a similar mean dose to the ITV (100.32 vs. 100.40%), with no significant differences between the plans in internal target coverage (5.37 vs. 4.96%). Similarly, no significant differences were observed between the maximal dose to the spinal cord (67.70 and 67.09%, respectively) and volume received 50% of the prescribed dose of: the liver (62.11 vs. 59.84%), the right (17.62 vs. 18.58%) and left kidney (29.40 vs. 30.48%). Set-up margins (SM) were computed as 7.80mm, 10.17mm and 6.71mm in the left-right, cranio-caudal and anterior-posterior directions, respectively. Presented IMRT protocol (OAR dose constraints with selected SM verified by 2DkV verification) for stomach treatment provided optimal dose distribution for the target and the critical organs. Comparison of DVH for the base and the modified plan (which considered set-up uncertainties) showed no significant differences.

Clinical outcomes following advanced respiratory motion management (respiratory gating or dynamic tumor tracking) with stereotactic body radiation therapy for stage I non-small-cell lung cancer

PurposeTo report the outcomes of stereotactic body radiation therapy (SBRT) for stage I non-small-cell lung cancer (NSCLC) according to respiratory motion management method.MethodsPatients with stage I NSCLC who received SBRT from 2007 to 2015 were reviewed. Computed tomography (CT) simulation with four-dimensional CT was performed for respiratory motion assessment. Tumor motion >1 cm in the craniocaudal direction was selectively treated with advanced respiratory management: either respiratory gating to a pre-specified portion of the respiratory cycle or dynamic tracking of an implanted fiducial marker. Comparisons were made with internal target volume approach, which treated all phases of respiratory motion.ResultsOf 297 patients treated with SBRT at our institution, 51 underwent advanced respiratory management (48 with respiratory gating and three with tumor tracking) and 246 underwent all-phase treatment. Groups were similarly balanced with regard to mean age (P=0.242), tumor size (P=0.315), and histology (P=0.715). Tumor location in the lower lung lobes, as compared to middle or upper lobes, was more common in those treated with advanced respiratory management (78.4%) compared to all-phase treatment (25.6%, P<.0001). There were 17 local recurrences in the treated lesions. Kaplan–Meier analyses showed that there were no differences with regard to mean time to local failure (91.5 vs 98.8 months, P=0.56), mean time to any failure (73.2 vs 78.7 months, P=0.73), or median overall survival (43.3 vs 45.5 months, P=0.56) between patients who underwent advanced respiratory motion management and all-phase treatment.ConclusionSBRT with advanced respiratory management (the majority with respiratory gating) showed similar efficacy to all-phase treatment approach for stage I NSCLC.

Accuracy analysis of the dose delivery process while using the Xsight® Spine Tracking technology

The Accuray CyberKnife® system provides radiotherapy for the treatment of moving lung tumors, thanks to the use of the Xsight® Lung Tracking technology for monitoring the motion of the target. However, there are situations in which this technology is not able to properly track the target. Thus, the aim of the proposed work is to study the accuracy of the dose delivery process while using the Xsight® Spine Tracking technology, which helps to overcome the aforementioned issue. The CIRS Dynamic Thorax Phantom was used to simulate the motion of a spherical target (diameter 2 cm), which moves along the craniocaudal direction (motion 3 cm). Monte Carlo algorithm calculated PTV and ITV treatment plans for isocentric and non-isocentric irradiation methods. Ionization Chamber and Film Dosimetry measurements were performed to study the accuracy of the dose delivery process to the center, and to the periphery of the tumor. Results obtained through the implementation of the PTV treatment plans were used as a baseline to analyze the accuracy of dose delivery for ITV plans. Although results indicated a decrease for the dose delivered compared to the planned one, the dose delivered was not lower than the prescribed one in any of the studied cases.

The development of the human notochord.

The notochord is a major regulator of embryonic patterning in vertebrates and abnormal notochordal development is associated with a variety of birth defects in man. Proper knowledge of the development of the human notochord, therefore, is important to understand the pathogenesis of these birth defects. Textbook descriptions vary significantly and seem to be derived from both human and animal data whereas the lack of references hampers verification of the presented data. Therefore, a verifiable and comprehensive description of the development of the human notochord is needed. Our analysis and three-dimensional (3D) reconstructions of 27 sectioned human embryos ranging from Carnegie Stage 8 to 15 (17–41 days of development), resulted in a comprehensive and verifiable new model of notochordal development. Subsequent to gastrulation, a transient group of cells briefly persists as the notochordal process which is incorporated into the endodermal roof of the gut while its dorsal side attaches to the developing neural tube. Then, the notochordal process embeds entirely into the endoderm, forming the epithelial notochordal plate, which remains intimately associated with the neural tube. Subsequently, the notochordal cells detach from the endoderm to form the definitive notochord, allowing the paired dorsal aortae to fuse between the notochord and the gut. We show that the formation of the notochordal process and plate proceeds in cranio-caudal direction. Moreover, in contrast to descriptions in the modern textbooks, we report that the formation of the definitive notochord in humans starts in the middle of the embryo, and proceeds in both cranial and caudal directions.

Intensity-Modulated Radiation Therapy for Multiple Targets with Tomotherapy Using Multiple Sets of Static Ports From Different Angles - Pseudo Dynamic-Jaw and Dynamic-Couch Technique

Helical tomotherapy is suitable for irradiating multiple targets at once. However, treatment time becomes long when the targets are separated in craniocaudal direction, since the couch moves slowly at a uniform pace. The dynamic-jaw and dynamic-couch (DJDC) mode offers dynamic jaw alignment throughout the treatment and variable couch speeds allowing faster movement in unirradiated parts of the body, but it is not yet available for clinical use. To solve the problem of long treatment time, we invented a new technique using multiple static-port tomotherapy with the dynamic-jaw mode and named it pseudo-DJDC (pDJDC) technique. We compared the pDJDC plans and helical tomotherapy plans using the dynamic-jaw mode (HDJ) for multiple targets. In pDJDC plans, we use a beam set with 4-6 ports to the targets at the same level in the craniocaudal direction and employ another beam set for other targets using different port angles (9-12 angles in total). The couch moves fast during the intervals between the different beam sets. In 7 patients, 2 plans using the pDJDC and HDJ techniques were compared. Four of the 7 patients had multiple (n=2-6) distant metastases including those to the rib and lymph node and peritoneal dissemination. Two patients had esophageal cancer with 3 targets including a primary tumor and regional metastases. The other patient had 2 pleural disseminations from a thymic tumor. For multiple distant metastases, 25-40 Gy in 2- to 5-Gy fractions were prescribed for the planning target volumes at D50%. For esophageal cancer, 20-22 Gy in 2-Gy fractions were prescribed as boost plans. For thymic tumor, 60 Gy in 7.5-Gy fractions were prescribed. Conformity index, uniformity index (D5%/D95%), dose distribution in the lung, and beam-on time were evaluated using Wilcoxon signed-rank test. The median conformity index of all 7 patients was 3.0 for the pDJDC plans and 2.4 for the HDJ plans (p = .031). The median uniformity index of the planning target volume (n=25) for the 2 plans was 1.048 and 1.057, respectively (p = .10). For 5 patients with thoracic targets, the median of the mean lung dose was 2.6 Gy and 2.4 Gy, respectively (p = .63). The median V5Gy and V20Gy of the lung in the 5 patients were 11.8% and 8.5% (p = .63) and 1.6% and 2.1% (p = .32), respectively. The pDJDC plans reduced the beam-on time by 52% compared to the HDJ plans (median; 421 and 883 seconds, respectively, p = .016) The pDJDC technique enables treatment of multiple targets in half time compared to the HDJ technique. The pDJDC plans were comparable to the HDJ plans in dose distribution except the conformity index.

Patterns of Local Extension and Nodal Involvement From 1300 Nasopharyngeal Carcinoma Patients Based on Magnetic Resonance Imaging

To clarify the biological behavior of nasopharyngeal carcinoma by exploring patterns of local extension and nodal involvement. To offer our suggestions for clinical target volume delineation. We retrospectively reviewed the imaging documents of 1300 consecutive cases of newly diagnosed nasopharyngeal carcinoma between January 2012 and December 2016. According to the incidence rates of tumor invasion, the anatomic sites were classified into three groups: high-risk group (≥50%), medium-risk group (≥10%∼<50%), low-risk group (<10%). The location of lymph nodes was determined based on the 2013 updated guidelines for neck node levels. Furthermore, we proposed a novel clinical classification according to patterns of local extension and nodal metastasis.Abstract MO_6_2508; Table 1Local TypeSuperior TypeInferior TypeMix Typeskull base and/or intracranial extension-+-+lymph nodes metastasis--++ Open table in a new tab The incidence rates of tumor invasion were between 0.2% and 91.2%. Local extension invaded across the midline in 95.2% cases. If anatomic sites in high-risk group or median-risk group were involved, the incidence rates of tumor invasion in adjacent medium-risk sites or low-risk group were increased. On the contrary, the incidence rates were decreased when the adjacent high-risk sites or median-risk group were not involved. 85.9% cases had involved lymph nodes. The frequency of skip metastases was only 3.9%. The necrosis rate of lymph nodes was 37.8% and the rate of extracapsular spread was 46.5%. The incidence rates of nodal involvement were increased when adjacent upper nodal level was involved. Among four clinical types, the mix type has the highest rate, reaching 40.5%. No significant correlation was found between T stage and nodal involvement (χ2=14.469，P=0.107). In patients presenting with nasopharyngeal carcinoma, local disease spreads stepwise from proximal sites to more distal sites. The invasion rates of medium-risk sites and low-risk sites are related to the involvement of adjacent high-risk and median-risk sites. The frequency of metastases in the jugular lymph node chains decreased in the cranio-caudal direction. Both solitary metastases and skip metastases are rare. The incidence rates of nodal metastasis are related to the involvement of adjacent upper nodal level. The most common clinical type of NPC is the invasion of skull bone, intracranial sites, along with neck node metastasis.

Long-Term Follow-Up of Oligometastases Patients Treated with Hypofractionated, Stereotactic Radiation Therapy (HSRT) on a Prospective Study

To analyze the long-term follow up of patients treated with HSRT for oligometastases from non-breast malignancies. From 2001-2006, 82 non-breast cancer patients with 1-5 radiographically apparent metastatic lesions were enrolled on a prospective study of HSRT. The eligibility requirements included age ≥ 18 y, KPS ≥ 70, and metastases to 1-3 organ sites. Net GTV represents the sum of each lesion’s contoured GTV, and was grouped into five categories (<20, 20-40, 40-60, 60-80, and >100cc). A stereotactic x-ray was used. The PTV was generated with a volumetric GTV expansion of 10 mm in the craniocaudal direction and 7 mm in other directions, and was covered by the 80% isodose line. FFDM was defined from date of enrollment until death, an event (i.e. widespread distant metastasis not amenable to local therapy), or last radiographic study. Lesion local recurrence was scored as an event if pathologically confirmed or if increased by ≥20% using RECIST criteria. Prognostic variables were assessed using Cox regression analysis, and FFDM and OS rates were calculated using Kaplan-Meier survival analysis. The mean age was 61 ± 11 y with a male to female ratio of 46/36. The most common histologies were adenocarcinoma (61%), squamous cell carcinoma (9%), and sarcoma (9%). The most common metastatic sites were liver (50%), lung (48%), thoracic lymph nodes (18%), and bone (5%). 61 had 1 involved organ and 18 had 1 lesion treated. 50 Gy in 10 fractions (52/82 patients) was the preferred schedule. The mean and median net GTV were 32 and 55 ml respectively (range 0.3-422). Other analyzed variables included prior curative-intent local therapy (35%), previously had >5 metastatic lesions (20%), and systemic therapy at some point after diagnosis of metastatic disease (74%). The median follow-up was 1.7 y (and 13.4 y for 4 of 82 patients alive at last follow-up). Eleven patients lived >5 years, and 6 lived >10 years. The 5-year OS, FFDM, and LC rates were 13.4%, 13.6%, and 62.2%, and the 10-y OS, FFDM, and LC rates were 7.3%, 12.3%, and 61.0%, respectively. On both univariate (UV) and multivariate (MV) analysis, net GTV was the only variable significant for OS (MV p=0.034, HR 1.36). GTV also proved to be significant on UV and MV (p=0.039, HR 2.31) for lesion LC. Having more than one organ involved with metastasis was not significant on UV (p=0.49) but was significant on MV analysis (p=0.020) for local control. Analysis for FFDM showed that net GTV was not a significant factor. On MV analysis, systemic therapy during metastatic diagnosis was significantly associated with FFDM (p=0.046, HR 0.47). Select non-breast cancer patients with limited metastasis treated with HSRT are long-term survivors. Net GTV is a significant factor for tumor control and survival. By 5 years, only 1 in 8 patients treated remained free from distant metastasis. Further research is needed to help better select patients most likely to benefit from local therapy for metastatic disease.

Effect of a Device-Free Compressed Shell Fixation Method on Hepatic Respiratory Movement

Various abdominal compression methods using some mechanical devices have been reported to suppress tumor and organ motions during irradiation. In particle therapy, however, it is desirable not to place such a device near the irradiation field to prevent deterioration of dose distribution due to scattering. Therefore, we developed a device-free compressed shell fixation method and have treated liver tumors using this system. This study examined the effect of suppressing respiratory motion of the liver by this method. This was a part of clinical studies for primary hepatocellular carcinoma and metastatic liver tumor using proton beam therapy based on protocols elaborated at Nagoya Proton Therapy Center and approved by the institutional review board. 146 patients (102 males and 44 females) with fiducial markers placed in the vicinity of the target tumor prior to proton beam therapy were included in this study. The patients were fixed to the couch using a thermoplastic shell made of polycaprolactone resin (ESFORM; Engineering System Co., Ltd., Nagano, Japan). When this shell was shaped to fit the patient’s body, a beanbag weighing 2, 3, or 5 kg was placed on the epigastrium of the patient for the purpose of suppressing the respiratory movement of the liver. After the shell cooled down and the beanbag was removed, the device-free compressed shell was completed. After making the shell, the patient was instructed to breathe about 14 times per minute, and finally 4D-CT for treatment planning was taken. The magnitude of respiratory movement of the liver was calculated by analyzing the coordinates in the cranio-caudal direction of the fiducial marker from the X-ray fluoroscopic images at the time of shell molding and 4DCT for treatment planning. The magnitude of suppression indicating the overall effect of the shell fixation and breathing method instruction was calculated by subtracting the magnitude of respiratory movement at the 4D-CT from the value before making the shell for each patient. The median respiratory movement before making the shell, after fixing with the shell, and after instructing the breathing method were 14.2 mm (interquartile range (IQR), 10.7-19.8), 11.5 mm (IQR, 8.6-17.5), and 10.4 mm (IQR, 7.3-15.8), respectively. These values were significantly different in Kruskal-Wallis test. The median magnitude of suppression was 3.9 mm (IQR, 1.3-7.8). There was no significant difference in the magnitude of suppression according to the weight of the beanbag, sex, and BMI. The patient group wearing a shell made with the 5-kg beanbag had a significant variability in the value in Mann-Whitney U-test. The device-free compressed shell fixation method was efficient in suppressing respiratory movement of the liver. This method requires no device for abdominal compression, so compatibility may be good, especially for particle beam therapy.

In vitro biomechanical evaluation of a monocoque plate-spacer construct for cervical open-door laminoplasty.

PurposeTo evaluate biomechanical differences between two surgical procedures for cervical open-door laminoplasty using human cadaveric spines.MethodsTwenty-four cervical vertebrae (C4-C6) from eight fresh-frozen human cervical spines were subjected to mechanical testing after being instrumented for open-door laminoplasty using a newly designed plate-spacer device with a monocoque structure (plate-spacer group; n = 12) or by conventional miniplate-alone fixation (miniplate group; n = 12). Cantilever bending testing was performed by applying a compressive load in the cranio-caudal direction to the base of the spinous process of the reconstructed laminar arch constructs until failure and strength and stiffness of the laminar arch were determined. The results are presented as mean ± standard deviation.ResultsThe plate-spacer group was approximately twice as strong as the miniplate group (27.6 ± 16.5 N vs. 13.5 ± 7.3 N, p < 0.05). Stiffness in the plate-spacer group exhibited the same trend (19.6 ± 9.3 N/mm vs. miniplate group: 11.4 ± 6.9 N/mm, p < 0.05).ConclusionThe fixation with the monocoque plate-spacer construct for open-door laminoplasty provided higher structural properties when compared against the plate-alone fixation. The spacer in the plate-spacer construct appears to contribute by preventing large deformations of the laminar arch caused by bending in cranio-caudal direction. Future studies will be required to investigate stress/strain distribution in the laminar arch constructs.

Effect of a Device-Free Compressed Shell Fixation Method on Hepatic Respiratory Movement: Analysis for Respiratory Amplitude of the Liver and Internal Motions of a Fiducial Marker

PurposeSuppression of respiratory movement of the liver would be desirable for high-precision radiation therapy for liver tumors. We aimed to investigate the effect of our original device-free compressed shell fixation method and breathing instruction on suppression of respiratory movement. The characteristics of liver motion based on the movement of a fiducial marker were also analyzed. Methods and MaterialsFirst, respiratory amplitudes of the liver with the device-free compressed shell were analyzed from the data of 146 patients. The effect of this shell fixing method on liver movement was evaluated. Second, as another cohort study with 166 patients, interfractional internal motion of the liver for patients fixed in the shell was calculated using the fiducial marker coordinate data of images for position setting before daily irradiation. Third, in another 12 patients, intrafractional internal motion was calculated from the fiducial marker coordinate data using x-ray images before and after irradiation. ResultsThe median respiratory movement without the shell, after fixing with the shell, and after instructing on the breathing method with the shell was 14.2 (interquartile range, 10.7-19.8), 11.5 (8.6-17.5), and 10.4 mm (7.3-15.8), respectively. Systematic and random errors of interfractional internal motion were all ≤2 mm in the left-right and anteroposterior directions and 3.7 and 3.0 mm, respectively, in the craniocaudal direction. Systematic and random errors of intrafractional internal motion were all ≤1.3 mm in the left-right and anteroposterior directions and 0.8 and 2.4 mm, respectively, in the craniocaudal direction. ConclusionsThe device-free compressed shell fixation method was effective in suppressing the respiratory movement of the liver. Irradiation position matching using the fiducial marker can correct the interfractional internal motion on each day, which would contribute to the reduction of the margin to be given around the target.

Characteristics of the paralysed diaphragm studied by M‐mode ultrasonography

M-mode ultrasonography might be useful for detecting hemidiaphragm paralysis. The objective of the present study was to describe the motion recorded by M-mode ultrasonography of both diaphragmatic leaves in patients with a pre-established diagnosis of hemidiaphragm paralysis. A study was conducted in 26 patients (18 men, 8 women) with unilateral diaphragmatic paralysis. They were referred to two different rehabilitation centres after thoracic surgery in 23 cases and cardiac interventional procedures in three cases. The pulmonary function tests and the study of the diaphragmatic motion using M-mode ultrasonography were recorded. The pulmonary function tests showed a restrictive pattern. The M-mode ultrasonography reported either the absence of motion or a weak paradoxical (cranial) displacement (less than 0·5cm) of the paralysed hemidiaphragm during quiet breathing. A paradoxical motion was recorded in all patients during voluntary sniffing, reaching around -1cm. During deep breathing, a paradoxical motion at the beginning of the inspiration was observed. Thereafter, a re-establishment of the motion in the craniocaudal direction was recorded. The excursions measured on the healthy side, during quiet breathing and voluntary sniffing, were increased in patients suffering from contralateral hemidiaphragm paralysis, when compared with 170 healthy volunteers. To detect diaphragmatic dysfunction in patients at risk, it would be useful to study diaphragmatic motion by M-mode ultrasonography during quiet breathing, voluntary sniffing and deep breathing.