Tumor Position Research Articles

An analytical and comparative study of swallowing in a tumor-infected oesophagus: a mathematical model.

This study discusses non-steady effects encountered in peristaltic flows in oesophagus. The purpose of this communication is to evolve a mechanism to diagnose tumor in an oesophagus mathematically. The tumor is modelled by generic bump function of certain height and width. The method of solution follows long wavelength and low-Reynolds number approximations for unsteady flow, while integrations have been performed numerically in order to plot graphs, which reveal various characteristics of the flow. The goal is to assess how pressure varies across the tumor's width. The spatial, as well as temporal, dependence of pressure has been studied in the laboratory frame of reference. The pressure distribution for tumor-infected oesophagus is compared with that of normal oesophagus. An intensified pressure is obtained in the presence of tumor. The interruption while swallowing through benign oesophageal tumor is confirmed by an abrupt pressure rise across the tumor's width. Tumor position also plays a significant role whether it is at contraction or relaxation of walls. Additionally, wall-shear-stress, volumetric flow rate and streamlines have also been described and compared with that without tumor growth. The expressions corresponding to all the physical quantities are computed numerically. Further, this model may also be implemented to the two-dimensional channel flow for an industrial application.

Guided placement of zygomatic implants in head and neck cancer patients: implant survival and patient outcomes at 1–3 years of follow-up

Zygomatic implants (ZI) are a valuable option for supporting an obturator prosthesis after maxillary resection. This study was performed to assess the clinical outcomes of a digitally validated guided technique for ZI placement, followed by immediate prosthetic obturation. The primary objective was to evaluate implant survival, while the secondary objective was to assess patient-reported quality of life post-rehabilitation. Twelve patients treated for head and neck cancer received a total of 36 ZI after ablative surgery. The mean duration of ZI follow-up was 30.1 months. The survival rate of ZI placed in non-irradiated patients was 100%, while it was 85% in irradiated patients. Patient-reported outcomes were evaluated using the Liverpool Oral Rehabilitation Questionnaire (LORQv3) and the University of Washington Quality of Life Questionnaire (UW-QOL v4). Most patients reported satisfactory outcomes in the oral function domain of the LORQv3 (mean score 17.7 ± 4.5; possible range 12–48, with lower scores indicating better outcomes). Regarding the UW-QOL v4, the swallowing and chewing domains had the highest scores (mean 97.5 ± 8.7 and 95.8 ± 14.4, respectively; maximum possible score of 100). In conclusion, this treatment approach improves function and quality of life after maxillary ablative surgery. However, irradiated patients showed a noticeable trend of higher implant failure, and this was influenced by tumour position and size impacting the radiation dose to the zygomatic bone.

Dose-escalated SBRT for borderline and locally advanced pancreatic cancer. Feasibility, safety and preliminary clinical results of a multicenter study

BackgroundPancreatic Stereotactic Body Radiotherapy (SBRT) allows for the administration of a higher biologically effective doses (BED), that would be essential to achieve durable tumor control. Escalating treatment doses need a very accurate tumor positioning and motion control during radiotherapy.The aim of this study to assess the feasibility and safety of a Simultaneous Integrated Boost (SIB) dose-escalated protocol at 45 Gy, 50 Gy and 55 Gy in 5 consecutive daily fractions, in Border Line Resectable Pancreatic Cancer (BRCP) /Locally Advanced Pancreatic Cancer (LAPC) by means of a standard LINAC platform. MethodsPatients diagnosed of BRPC/LAPC, candidates for neoadjuvant chemotherapy and SBRT, in four university hospitals of the province of Las Palmas (Canary Islands, Spain) were included in this prospective study. Radiotherapy was administered using standard technology (LINACS) with advanced positioning (Lipiodol® and metallic stent used as fiducial markers) and tumor motion control (4D, DBH, Calypso®). There were 3 planned dose-escalated SIB groups, 45 Gy/5f (9 patients) 50 Gy/5f (9 + 9 patients) and 55 Gy/5f (9 patients). The defined primary end points of the study were the safety and feasibility of the proposed treatment protocol. Secondary endpoints included radiological tumor response after SBRT, local control and survival. ResultsFrom June 2017 to December 2022, sixty-two patients were initially assessed for eligibility in the study in the four participating centers, and 49 were candidates for chemotherapy (CHT). Forty-one were referred to radiotherapy after CHT and 33 finally were treated by escalated-dose SIB, 45 Gy (9 patients) 50 Gy (16 patients), 55 Gy(8 patients). All patients completed the scheduled treatment and no acute or late severe (≥grade3) gastrointestinal toxicity was observed.Local response was analyzed by CT/MRI two months after the end of SBRT. Ten patients (31,25 %) achieved objective response (2/9:45 Gy, 5/15:50 Gy, 3/8:55 Gy). Follow-up was closed as July 2023. Freedom from local progression at 1-2y were 89,3% (95 %CI:83,4–95,2%) and 66 % (95 %CI:54,6–77,4%) respectively. The 1-2y survival rates were 95,7% (95 %CI:91,4–100 % and 48,6% (95 %CI:37,7–59,5%) respectively. ConclusionThese promising results should be confirmed by further studies with larger sample size and extended follow-up period.

Clinical application of combination [11C]C-methionine and [13N]N-ammonia PET/CT in recurrent functional pituitary adenomas with negative MRI or [18F]F-FDG PET/CT

BackgroundWe assessed the value of positron emission tomography/computed tomography (PET/CT) with [13N]N-ammonia ([13N]N-NH3) and [11C]C-methionine ([11C]C-MET) for the evaluation and management of recurrent secreting pituitary adenoma, which could not be detected by magnetic resonance imaging (MRI) or fluorine-18 fluorodeoxyglucose ([18F]F-FDG) PET.MethodsNine consecutive patients with biochemical and clinical evidence of active recurrent tumor not detected by MRI and [18F]F-FDG PET were enrolled in this study. All of the patients underwent [13N]N-NH3 and [11C]C-MET PET/CT, after which the pattern of tracer uptake was studied, the tumor position was located, and a clinical decision was made.ResultsIn general, [11C]C-MET had a higher uptake in pituitary adenomas (PAs) than that in pituitary tissues, while [13N]N-NH3 had a higher uptake in pituitary tissue than in pituitary adenomas. Increased [11C]C-MET uptake was observed in all nine PAs and three pituitary tissues, while all pituitary tissues and only one pituitary adenoma showed increased [13N]N-NH3 uptake. Four patients had concordant imaging and surgical findings indicative of biochemical remission without hypopituitarism after treatment. Radiotherapy was adopted in two patients, medication in another two, and follow-up observation in one case.ConclusionCombined [11C]C-MET and [13N]N-NH3 PET/CT is effective in the differentiation of PAs from pituitary tissue in recurrent functional PAs with negative MRI or [18F]F-FDG PET. These results provide a valuable reference for further disease management.

Laparoscopic liver resection versus radiofrequency ablation for caudate lobe solitary hepatocellular carcinoma: A propensity score matching study.

This study aimed to compare the clinical efficacy of laparoscopic liver resection (LLR) and radiofrequency ablation (RFA) in treating solitary hepatocellular carcinoma (HCC) of the hepatic caudate lobe. Patients with hepatic caudate lobe HCC who underwent LLR or RFA at three hospitals in China between February 2015 and February 2021 were included. In total, 112 patients met the inclusion criteria, of whom 52 underwent RFA and 60 underwent LLR. The outcomes of the two groups were compared and analyzed using propensity score matching (PSM) method. There were no significant differences between the two groups in terms of sex, HBV/HCV positivity, AFP positivity (>100 ng/mL), tumor position, Child-Pugh score, or preoperative liver function tests (ALT, AST, TBIL, ALB, and PT) (p > 0.05). Compared to the LLR group, the RFA group had a shorter operation time, less intraoperative bleeding, and shorter postoperative hospital stay (p < 0.05). There was no statistically significant difference in overall postoperative complications between the two groups (p > 0.05). Despite the larger tumor size, the LLR group had better postoperative recurrence-free survival (RFS) (p = 0.00027) and overall survival (OS) (p = 0.0023) than the RFA group. After one-to-one PSM, 31 LLR patients and 31 RFA patients were selected for further analyses. The advantages of LLR over RFA were observed in terms of RFS (p < 0.0001) and OS (p = 0.00029). LLR should probably be recommended as the preferred method for solitary caudate lobe HCC.

Position Prior Attention Network for Pancreas Tumor Segmentation.

Segmentation of pancreatic tumors on CT images is essential for the diagnosis and treatment of pancreatic cancer. However, low contrast between the pancreas and the tumor, as well as variable tumor shape and position, makes segmentation challenging. To solve the problem, we propose a Position Prior Attention Network (PPANet) with a pseudo segmentation generation module (PSGM) and a position prior attention module (PPAM). PSGM and PPAM maps pancreatic and tumor pseudo segmentation to latent space to generate position prior attention map and supervises location classification. The proposed method is evaluated on pancreatic patient data collected from local hospital and the experimental results demonstrate that our method can significantly improve the tumor segmentation results by introducing the position information in the training phase.

Real-time nonstandard-shaped gold fiducial marker tracking on x-ray fluoroscopic images for prostate radiotherapy

Objective. The prostate moves in accordance with the movement of surrounding organs. Tumor position can change by ≥3 mm during radiotherapy. Given the difficulties of visualizing the prostate fluoroscopically, fiducial markers are generally implanted into the prostate to monitor its motion during treatment. Recently, internally motion guidance methods of the prostate using a 99.5% gold/0.5% iron flexible notched wire fiducial marker (Gold Anchor® , Naslund Medical AB, Huddinge, Sweden), which requires a 22 gauge needle, has been used. However, because the notched wire can retain its linear shape, acquire a spiral shape, or roll into an irregular ball, detecting it on fluoroscopic images in real-time incurs higher computation costs. Approach. We developed a fiducial tracking algorithm to achieve real-time computation. The marker is detected on the first image frame using a shape filter that employs inter-class variance for the marker likelihood calculated by the filter, focusing on the large difference in densities between the marker and its surroundings. After the second frame, the marker is tracked by adding to the shape filter the similarity to the template cropped from the area around the marker position detected in the first frame. We retrospectively evaluated the algorithm’s marker tracking accuracy for ten prostate cases, analyzing two fractions in each case. Main results. Tracking positional accuracy averaged over all patients was 0.13 ± 0.04 mm (mean ± standard deviation, Euclidean distance) and 0.25 ± 0.09 mm (95th percentile). Computation time was 2.82 ± 0.20 ms/frame averaged over all frames. Significance. Our algorithm successfully and stably tracked irregularly-shaped markers in real time.

A Multimodal Point Cloud-Based Method for Tumor Localization in Robotic Ultrasound-Guided Radiotherapy.

Objectives: Part of the tumor localization methods in radiotherapy have poor real-time performance and may generate additional radiation. We propose a multimodal point cloud-based method for tumor localization in robotic ultrasound-guided radiotherapy, which only irradiates computed tomography (CT) during radiotherapy planning to avoid additional radiation. Methods: The tumor position was determined using the CT point cloud, and the red green blue depth (RGBD) point cloud was used to determine body surface scanning location corresponding to the tumor location. The relationship between the CT point cloud and RGBD point cloud was established through multi-modal point cloud registration. The point cloud was then used for robot tumor localization through coordinate transformation between camera and robot. Results: The maximum mean absolute error of the tumor location in the X, Y, and Z directions of the robot coordinate system were 0.781, 1.334, and 1.490 mm, respectively. The average point-to-point translation mean absolute error between the actual and predicted positions of the localization points was 1.847 mm. The maximum error in the random positioning experiment was 1.77 mm. Conclusion: The proposed method is radiation free and has real-time performance, with tumor localization accuracy that meets the requirements of radiotherapy. The proposed method, which potentially reduces the risks associated with radiation exposure while ensuring efficient and accurate tumor localization, represents a promising advancement in the field of radiotherapy.

A brain tumor identification using convolution neural network in the deep learning

Brain tumors cause a lot of suffering; resulting in many illnesses they are properly handled. The diagnosis is part of the treatment of tumors. Proper and appropriate tumor identification is used to identify benign and malignant tumors. The key issue that leads to a rise in cancer affecting people across the globe is the irresponsible conduct towards the handling of gossip in its early stages. Includes noise reduction, image sharpening along with certain morphological functions, dilution, and erosion to get the context. The negative of the background-subtracted from the separate picture sets resulting in an isolated representation of the brain tumor. Image ting the contour vs. the c-label of growth is the border that makes it all the more useful to imagine and diagnose in order relevant to the tumors. The method determines the form, position, and size of the brain tumor.

TransUNet for Precise and Robust GI tract Segmentation in MRI Images

Medical image processing is revolutionizing Gastrointestinal (GI) cancer radiation therapy by enabling precise targeting of high X-ray beam dosages to the tumors while protecting the surrounding healthy organs. However, the manual segmentation of healthy organs at risk from MR-Linac images is a time-consuming process that can delay treatment and increase patient suffering. Deep learning-based medical image processing algorithms have the potential to automate the segmentation of organs at risk, thereby improving the accuracy and efficiency of GI cancer radiation therapy. Every day, the MR-Linac, a cutting-edge MRI technology, tracks the ever-changing positions of tumors. This advanced tool empowers medical professionals to fine-tune cancer treatments with remarkable precision. This study presents a TransUNet model, a combination of transformer architecture with Convolutional Neural Networks (CNNs). TransUNet achieves remarkable results in segmenting and labeling different regions within images by integrating the spatial comprehension of CNNs with the self-attention mechanisms of transformers. Our research compares the TransUNet model with various combinations of loss functions. The model outperforms with Dice+BCE loss function.

Cascaded Inner-Outer Clip Retformer for Ultrasound Video Object Segmentation.

Computer-aided ultrasound (US) imaging is an important prerequisite for early clinical diagnosis and treatment. Due to the harsh ultrasound (US) image quality and the blurry tumor area, recent memory-based video object segmentation models (VOS) achieve frame-level segmentation by performing intensive similarity matching among the past frames which could inevitably result in computational redundancy. Furthermore, the current attention mechanism utilized in recent models only allocates the same attention level among whole spatial-temporal memory features without making distinctions, which may result in accuracy degradation. In this paper, we first build a larger annotated benchmark dataset for breast lesion segmentation in ultrasound videos, then we propose a lightweight clip-level VOS framework for achieving higher segmentation accuracy while maintaining the speed. The Inner-Outer Clip Retformer is proposed to extract spatialtemporal tumor features in parallel. Specifically, the proposed Outer Clip Retformer extracts the tumor movement feature from past video clips to locate the current clip tumor position, while the Inner Clip Retformer detailedly extracts current tumor features that can produce more accurate segmentation results. Then a Clip Contrastive loss function is further proposed to align the extracted tumor features along both the spatial-temporal dimensions to improve the segmentation accuracy. In addition, the Global Retentive Memory is proposed to maintain the complementary tumor features with lower computing resources which can generate coherent temporal movement features. In this way, our model can significantly improve the spatial-temporal perception ability without increasing a large number of parameters, achieving more accurate segmentation results while maintaining a faster segmentation speed. Finally, we conduct extensive experiments to evaluate our proposed model on several video object segmentation datasets, the results show that our framework outperforms state-of-theart segmentation methods.

The first clinical implementation of real-time 6 degree-of-freedom image-guided radiotherapy for liver SABR patients

PurposeMultiple survey results have identified a demand for improved motion management for liver cancer IGRT. Until now, real-time IGRT for liver has been the domain of dedicated and expensive cancer radiotherapy systems. The purpose of this study was to clinically implement and characterise the performance of a novel real-time 6 degree-of-freedom (DoF) IGRT system, Kilovoltage Intrafraction Monitoring (KIM) for liver SABR patients. Methods/MaterialsThe KIM technology segmented gold fiducial markers in intra-fraction x-ray images as a surrogate for the liver tumour and converted the 2D segmented marker positions into a real-time 6DoF tumour position. Fifteen liver SABR patients were recruited and treated with KIM combined with external surrogate guidance at three radiotherapy centres in the TROG 17.03 LARK multi-institutional prospective clinical trial. Patients were either treated in breath-hold or in free breathing using the gating method. The KIM localisation accuracy and dosimetric accuracy achieved with KIM + external surrogate were measured and the results were compared to those with the estimated external surrogate alone. ResultsThe KIM localisation accuracy was 0.2±0.9 mm (left–right), 0.3±0.6 mm (superior-inferior) and 1.2±0.8 mm (anterior-posterior) for translations and −0.1◦±0.8◦ (left–right), 0.6◦±1.2◦ (superior-inferior) and 0.1◦±0.9◦ (anterior-posterior) for rotations. The cumulative dose to the GTV with KIM + external surrogate was always within 5% of the plan. In 2 out of 15 patients, >5% dose error would have occurred to the GTV and an organ-at-risk with external surrogate alone. ConclusionsThis work demonstrates that real-time 6DoF IGRT for liver can be implemented on standard radiotherapy systems to improve treatment accuracy and safety. The observations made during the treatments highlight the potential false assurance of using traditional external surrogates to assess tumour motion in patients and the need for ongoing improvement of IGRT technologies.

Design study of a novel geometrical arrangement for an in-beam small animal positron emission tomography scanner

Objective. We designed a geometrical solution for a small animal in-beam positron emission tomography (PET) scanner to be used in the project SIRMIO (Small animal proton irradiator for research in molecular image-guided radiation-oncology). The system is based on 56 scintillator blocks of pixelated LYSO crystals. The crystals are arranged providing a pyramidal-step shape to optimize the geometrical coverage in a spherical configuration. Approach. Different arrangements have been simulated and compared in terms of spatial resolution and sensitivity. The chosen setup enables us to reach a good trade-off between a solid angle coverage and sufficient available space for the integration of additional components of the first design prototype of the SIRMIO platform. The possibility of moving the mouse holder inside the PET scanner furthermore allows for achieving the optimum placement of the irradiation area for all the possible tumor positions in the body of the mouse. The work also includes a study of the scintillator material where LYSO and GAGG are compared with a focus on the random coincidence noise due to the natural radioactivity of Lutetium in LYSO, justifying the choice of LYSO for the development of the final system. Main results. The best imaging performance can be achieved with a sub-millimeter spatial resolution and sensitivity of 10% in the center of the scanner, as verified in thorough simulations of point sources. The simulation of realistic irradiation scenarios of proton beams in PMMA targets with/without air gaps indicates the ability of the proposed PET system to detect range shifts down to 0.2 mm. Significance. The presented results support the choice of the identified optimal design for a novel spherical in-beam PET scanner which is currently under commissioning for application to small animal proton and light ion irradiation, and which might find also application, e.g. for biological image-guidance in x-ray irradiation.

The frequency of various spinal cord tumors (SCTs) in surgically treated patients at Shiraz Shahid Chamran Hospital from 2012 to 2022

Abstract Aim The incidence of spinal cord tumors (SCTs) in a population considering sex, age, histopathology, and emplacement position of tumors is different between various regions. Therefore, the present study aimed to evaluate the frequency of various SCTs in surgically treated patients in a reference spinal surgery center in Shiraz, Iran. Method Documented information related to 109 SCT patients surgically treated was collected from the archive of Shahid Chamran Hospital (the reference center of spinal cord surgery in the south of Iran) in Shiraz from 2012 to 2022. This information includes demographics, medical history, histology, and position of SCTs within the spinal cord. Result The population of patients included 65 men and 44 women, with a mean age of 44.7 years old. Most patients (26 cases) were in the age group of 50–59 years. Neurological function in most patients (51 cases) was equivalent to level D of the ASIA impairment scale (AIS), and the most common complaints of patients (83 cases) were related to pain. Finally, anatomic and histologic evaluations indicated that intradural and schwannoma tumors were the most common types of tumors, with 64 and 25 cases, respectively. Conclusions In the present study, most of the findings are consistent with the previous reports. Schwannoma and ependymoma tumors were the most common types of SCTs and the most common types of intramedullary tumors, respectively. The sixth decade of life was the most common age of incidence. Neurological function in most patients with SCT was equivalent to levels of D and E of AIS. However, regarding the factor of gender, our results are similar to those of the Asian population. More comprehensive studies in the future likely reveal the probable role of environmental, genetic, and hormonal factors in the etiology of SCTs.

Enhanced anti-tumor activity of arginine decarboxylase through the incorporation of aromatic amino acids at the multimer-forming interface.

The pressing challenge of cancer's high mortality and invasiveness demands improved therapeutic approaches. Targeting the nutrient dependencies within cancer cells has emerged as a promising approach. This study is dedicated to demonstrating the potential of arginine depletion for cancer treatment. Notably, the focus centers on arginine decarboxylase (RDC), a pH-dependent enzyme expecting enhanced activity within the slightly acidic microenvironments of tumors. To investigate the effect of a single-site mutation on the catalytic efficacy of RDC, diverse amino acids, including glycine, alanine, phenylalanine, tyrosine, tryptophan, p-azido-phenylalanine, and a phenylalanine analog with a hydrogen-substituted tetrazine, were introduced at the crucial threonine site (position 39) in the multimer-forming interface. Remarkably, the introduction of either a natural or a non-natural aromatic amino acid at position 39 substantially boosted enzymatic activity, while amino acids with smaller side chains did not show the same effect. This enhanced enzymatic activity is likely attributed to the reinforced formation of multimer structures through favorable interactions between the introduced aromatic amino acid and the neighboring subunit. Noteworthy, at slightly acidic pH, the RDC variant featuring tryptophan at position 39 demonstrated augmented cytotoxicity against tumor cells compared to the wild-type RDC. This attribute aligns with the tumor microenvironment and positions these variants as potential candidates for targeted cancer therapy.

Terahertz Microstrip Patch Antenna for Breast Tumour Detection

Breast cancer is one of the most common cancers among Malaysian women. It is critical to discover strategies to detect the tumour early on. Terahertz (THz) frequency provides excellent qualities for detecting tumours such as low photon energy and non-ionising radiation as compared to prior methods such as mammography, ultrasound, and magnetic resonance imaging (MRI) that use optical to X-ray frequencies. The purpose of this work is to analyse and locate a breast tumour as well as to compute the maximum specific absorption rate (SAR) value. It was designed a THz rectangular microstrip patch antenna with an inset feed. To improve the antenna's performance, graphene was used for the patch and polyimide for the substrate. This antenna covered a bandwidth of 31.6 GHz and worked in the frequency range of 0.283-0.599 THz. To identify the location of a tumour, compute the SAR value, and localise the tumour, SAR simulation was used. The maximum SAR shifted to the tumor's position due to greater absorption rate around its tissue due to higher dielectric constant features. It was calculated that 1e-05g of average mass is required to be less than total tissue mass, which is 2.0063e-05g. SAR study revealed a maximum SAR value of 2.49391e+06 W/kg, which was not more than the overall absorption rate for human body safety. The SAR calculation result revealed that the tumour is within the range of the tumor's initial location.

Radiological Biomarkers in MRI directed Rectal Cancer Radiotherapy Volume Delineation.

Our study evaluated whether an MRI reporting system highlighting areas of contiguous and discontinuous extramural venous invasion (EMVI) can improve the accuracy of gross tumour volume (GTV) delineation. Initially, 27 consecutive patients with locally advanced rectal cancer treated between 2012 and 2014 were evaluated. We used an MRI reporting proforma that documented the position of the primary tumour, lymph nodes and EMVI. The new GTVs delineated were compared with historical radiotherapy treatment volumes to identify the frequency of GTV geographical miss. We observed that the delineation of involved nodes and areas of EMVI was more likely to represent sources of uncertainty wherein nodal GTV geographical miss was evident in 5 out of 27 patients (19%). Complete EMVI GTV geographical miss occurred in two patients (7%). We re-evaluated our radiotherapy practice in a further 27 patients after the implementation of a modified MRI reporting system. An improvement was seen; nodal miss was observed in two patients (7%) and partial EMVI miss in one patient (4%), although these areas were encompassed in the planning target volume (PTV). Our study shows that extramural venous invasion and involved nodes need to be highlighted on MRI to improve the accuracy of rectal cancer GTV delineation.

Safety and efficacy of laparoscopic transperitoneal versus retroperitoneal resection for benign retroperitoneal tumors: a retrospective cohort study.

Benign retroperitoneal tumors (BRTs) are clinically rare solid tumors. This study aimed to compare the safety and efficacy of laparoscopic transperitoneal versus retroperitoneal resection for BRTs. The clinical data of 43 patients who had pathologically confirmed BRTs and underwent laparoscopic resection in a single center from January 2019 to May 2022 were retrospectively analyzed. Patients were divided into two groups according to the surgical methods: the Transperitoneal approach group (n = 24) and the Retroperitoneal approach group (n = 19). The clinical characteristics and perioperative data between the two groups were compared. The baseline data and surgical variables were analyzed to determine the impact of different surgical approaches on the treatment outcomes of BRTs. No significant difference was observed between the two groups in gender, age, body mass index, the American Society of Anesthesiologists score, presence of underlying diseases, tumor size, tumor position, operation duration, intraoperativehemorrhage, postoperative hospital stay, intestinalfunctionrecoverytime, and postoperative complication rate. The conversion rate from laparoscopic to open surgery was significantly lower in the Transperitoneal approach group than in the Retroperitoneal approach group (1/24vs.5/19, χ2 = 4.333,P = 0.037). Tumor size was an independent influencing factor for the effect of surgery (odds ratio = 1.869, 95% confidence interval = 1.135-3.078,P = 0.014) and had a larger efficacy on the retroperitoneal group (odds ratio = 3.740, 95% confidence interval = 1.044-13.394,P = 0.043). The laparoscopic transperitoneal approach has the inherent advantages of anatomical hierarchies and surgical space, providing a better optical perspective of the targeted mass and improved bleeding control. This approach may have better efficacy than the retroperitoneal approach, especially in cases of a large tumor or when the tumor is located near important blood vessels.

Volumetric tumor tracking from a single cone-beam X-ray projection image enabled by deep learning

Radiotherapy serves as a pivotal treatment modality for malignant tumors. However, the accuracy of radiotherapy is significantly compromised due to respiratory-induced fluctuations in the size, shape, and position of the tumor. To address this challenge, we introduce a deep learning-anchored, volumetric tumor tracking methodology that employs single-angle X-ray projection images. This process involves aligning the intraoperative two-dimensional (2D) X-ray images with the pre-treatment three-dimensional (3D) planning Computed Tomography (CT) scans, enabling the extraction of the 3D tumor position and segmentation. Prior to therapy, a bespoke patient-specific tumor tracking model is formulated, leveraging a hybrid data augmentation, style correction, and registration network to create a mapping from single-angle 2D X-ray images to the corresponding 3D tumors. During the treatment phase, real-time X-ray images are fed into the trained model, producing the respective 3D tumor positioning. Rigorous validation conducted on actual patient lung data and lung phantoms attests to the high localization precision of our method at lowered radiation doses, thus heralding promising strides towards enhancing the precision of radiotherapy.

Predicting Treatment Response of Esophageal Cancer Treated by Concurrent Chemoradiotherapy Using Pre- and Posttreatment 18F-FDG PET Metabolic Characteristics.

This study hypothesizes that metabolic characteristics of esophageal tumors can be used to predict treatment response, which considers changes in the primary tumor and lymph nodes, for patients receiving neoadjuvant concurrent chemoradiotherapy (CCRT). This study retrospectively included 60 esophageal cancer patients receiving CCRT followed by surgery. All patients received 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) examinations prior to CCRT and in the interval between CCRT and surgery. On the pre-treatment FDG PET/CT images, the maximum standardized uptake value (SUVMaxPre) within the primary tumor was identified. By computerized methods, the CT images of pre- and post-treatment FDG PET/CT were registered. Then, the coordinates of SUVMaxPre were transformed to the post-treatment FDG PET images and delineated a sphere with a diameter of 5 cm to indicate the tumor position. After excluding air, the sphere was partitioned into several metabolic volumes by the optimal dichotomy of high and low metabolic FDG uptakes. Finally, the volume with the shortest distance to the center was adopted and represented by the maximum standardized uptakes (SUVMaxPost). Two additional features, SUVDiff and SUVDiffR, were defined as SUVMaxPost - SUVMaxPre and (SUVMaxPost - SUVMaxPre) / SUVMaxPre. Besides, for defining treatment response, the patients with and without residual tumors were defined as ypT+ and ESOCR based on the histopathology results of surgery. The ESOCR was further classified into pCR to indicate the absence of lymph node metastasis and LNM for remaining. Finally, the area under the receiver operating characteristic curve analysis (AUC) was conducted to assess the features' ability to differentiate two treatment responses. Kruskal-Wallis test was used to evaluate the differences in features between treatment responses. Of the 60 patients, 55 were men (92%), and the mean age was 58. The number of tumors at the esophagus's upper, middle, and lower third were 8, 18, and 34, respectively. Ninety-eight percent of the tumors were squamous cell carcinomas (59/60). The patient numbers of ypT+ and ESOCR were 43 and 17 of which contained 13 pCR and 4 LNM. The SUVDiff and SUVDiffR exhibited a significant ability to identify the ESOCR with AUC = .337 (p = .05) and AUC = .290 (p = .012), respectively. In addition, a statistically significant difference was found among the three groups of ypT+, pCR, and LNM on SUVMaxPre (H = 6.252 and p = .044), SUVDiff (H = 7.948 and p = .019), and SUVDiffR (H = 8.405 and p = .015). In the post-hoc tests corrected by the Bonferroni, the difference between ypT+ and LNM was significant on these features. The metabolic characteristics extracted from pre- and post-treatment FDG PET/CT images could indicate treatment response and disease progression. Further studies are warranted.