Cell Accelerated Cryoablation Simulation

Article · October 2009with39 Reads
DOI: 10.1016/j.cmpb.2009.09.004 · Source: PubMed
Tumor cryoablation is a clinical procedure where supercooled probes are used to destroy cancerous lesions. Cryoablation is a safe and effective palliative treatment for skeletal metastases, providing immediate and long term pain relief, increasing mobility and improving quality of life. Ideally, lesions are encompassed by an ice ball and frozen to a sufficiently low temperature to ensure cell death. "Lethal ice" is the term used to describe regions within the ice ball where cell death occurs. Failure to achieve lethal ice in all portions of a lesion may explain the high recurrence rate currently observed. Tracking growth of lethal ice is critical to success of percutaneous ablations, however, no practical methods currently exist for non-invasive temperature monitoring. Physicians lack planning tools which provide accurate estimation of the ice formation. Simulation of ice formation, while possible, is computationally demanding and too time consuming to be of clinical utility. We developed the computational framework for the simulation, acceleration strategies for multicore Intel x86 and IBM Cell architectures, and performed preliminary validation of the simulation. Our results demonstrate that the streaming SIMD implementation has better performance and scalability. Both accelerated and non-accelerated algorithms demonstrate good agreement between simulation and manually identified ice ball boundaries in phantom and patient images. Our results show promise for the development of novel cryoablation planning tools with real-time monitoring capability for clinical use.
    • Several recent studies have shown that these techniques are effective treatment modalities for the local control of selected tumors with low complication rates (Flanders and Gervais 2010;McWilliams et al. 2010;Nakatsuka et al. 2010;Alpantaki et al. 2011;Chua 2011;Ferreira et al 2011;Iversen et al. 2011;Lian et al. 2011;McLeod et al. 2011;Yang et al. 2011). However, the efficacy of the treatment for tumors is not yet considered to be equivalent to resection, because freezing was not supposed to achieve the destruction of all tumor cells within the ice ball (Blezek et al. 2010). Although, an important method that has been suggested to cryonecrosis of tumorous tissue is cryocycling, which means repeated freezing of the target tissue with intermittent thawing periods (Kopelman et al. 2004).
    [Show abstract] [Hide abstract] ABSTRACT: Cryosurgery is an accepted method for treatment of various lesions. Cryoablation produces rapid freezing of tissues, which leads to cell death due to ice crystallization, desiccation, ischemia, and reperfusion injury during thawing. The beneficial effect of cryocycling, however, has not been universally accepted. In the present study, which was conducted on rabbits, we investigated healing processes after inducing injury by pulse cryocycling on normal liver tissue in vivo. The study was performed on 12 male Dutch rabbits (Oryctolagus cuniculus). A 20-mm diameter contacting probe was used to freeze parietal surface of the liver until the extending of ice ball was visible at the opposite visceral surface.After thawing, the probe was put on the same place and frozen again with equal duration of time as the first. The liver was returned to its normal location in the body and the abdominal and skin incisions were sutured. To evaluate liver injury and regeneration, injured and adjacent healthy tissues were harvested 1, 6 and 24 h, and 3,7,14 days after operation. Pieces of liver tissue were prepared for light microscopy. Connective tissue had completely separated the injured and healthy areas. Abundant capillaries and some new generated basophilic hepatocytes were seen around the central vein after 14 days post operation. Creation of granulation tissue and some regenerated hepatocytes with basophilic cytoplasm, in the 14th day of post operation period, shows ability of the surrounding cells to regenerate the normal tissue. Keywords Cryosurgery . Cryoablation . Healing . Liver . Oryctolagus cuniculus
    Article · Sep 2014
    • More advanced approaches have been proposed recently in the literature. They essentially rely on the same equation describing the heat diffusion through soft tissues [11,3,2]. The main criticism of all these different approaches is that they do not address some key requirements for being used in clinical routine.
    [Show abstract] [Hide abstract] ABSTRACT: Cryotherapy is a rapidly growing minimally invasive technique for the treatment of certain tumors. It consists in destroying cancer cells by extreme cold delivered at the tip of a needle-like probe. As the resulting iceball is often smaller than the targeted tumor, a key to the success of cryotherapy is the planning of the position and orientation of the multiple probes required to treat a tumor, while avoiding any damage to the surrounding tissues. In order to provide such a planning tool, a number of challenges need to be addressed such as fast and accurate computation of the freezing process or interactive positioning of the virtual cryoprobes in the pre-operative image volume. To address these challenges, we present an approach which relies on an advanced computational framework, and a gesture-based planning system using contact-less technology to remain compatible with a use in a sterile environment.
    Full-text · Article · Feb 2014
  • [Show abstract] [Hide abstract] ABSTRACT: While cryosurgery has proven capable in treating of a variety of conditions, it has met with some resistance among physicians, in part due to shortcomings in the ability to predict treatment outcomes. Here we attempt to address several key issues related to predictive modeling by demonstrating methods for accurately characterizing heat transfer from cryoprobes, report temperature dependent thermal properties for ultrasound gel (a convenient tissue phantom) down to cryogenic temperatures, and demonstrate the ability of convective exchange heat transfer boundary conditions to accurately describe freezing in the case of single and multiple interacting cryoprobe(s). Temperature dependent changes in the specific heat and thermal conductivity for ultrasound gel are reported down to -150 °C for the first time here and these data were used to accurately describe freezing in ultrasound gel in subsequent modeling. Freezing around a single and two interacting cryoprobe(s) was characterized in the ultrasound gel phantom by mapping the temperature in and around the "iceball" with carefully placed thermocouple arrays. These experimental data were fit with finite-element modeling in COMSOL Multiphysics, which was used to investigate the sensitivity and effectiveness of convective boundary conditions in describing heat transfer from the cryoprobes. Heat transfer at the probe tip was described in terms of a convective coefficient and the cryogen temperature. While model accuracy depended strongly on spatial (i.e., along the exchange surface) variation in the convective coefficient, it was much less sensitive to spatial and transient variations in the cryogen temperature parameter. The optimized fit, convective exchange conditions for the single-probe case also provided close agreement with the experimental data for the case of two interacting cryoprobes, suggesting that this basic characterization and modeling approach can be extended to accurately describe more complicated, multiprobe freezing geometries. Accurately characterizing cryoprobe behavior in phantoms requires detailed knowledge of the freezing medium's properties throughout the range of expected temperatures and an appropriate description of the heat transfer across the probe's exchange surfaces. Here we demonstrate that convective exchange boundary conditions provide an accurate and versatile description of heat transfer from cryoprobes, offering potential advantages over the traditional constant surface heat flux and constant surface temperature descriptions. In addition, although this study was conducted on Joule-Thomson type cryoprobes, the general methodologies should extend to any probe that is based on convective exchange with a cryogenic fluid.
    Article · Feb 2013
  • [Show abstract] [Hide abstract] ABSTRACT: This paper is aimed at investigating the capacity of using combined cryosurgical and hyperthermic modality for treating knee bone tumor with complex shape. An anatomical model for human knee was constructed and a three-dimensional (3D) finite element analysis was developed to determine temperature distribution of the tissues subject to single freezing (SF), single heating (SH) and alternate freezing-heating (AFH), respectively. The heat fluxes of the probes wall and the ablation volume are particularly tracked to comparatively evaluate the ablation ability of different probe configurations with varied diameter, number and active working length. As example, an effective conformal treatment strategy via one time's insertion while cyclic freezing-heating using multiple probes is designed for a predefined knee bone tumor ablation. Both SF and SH could create large enough ablation volume, while it is hard for them to perform a conformal treatment on irregular and slender knee tumor. As an alternative, AFH could form a flexible and controlled shape and volume of the ablation by changing the size and number of the probes and adjusting their insertion depth. In addition, a thermal protection method is considered to reduce cryoinjury of the health tissue.
    Article · Sep 2013
Conference Paper
January 2012
    【目的】腹腔鏡手術において対象臓器内部や背部を知ることは困難である.そこで本研究ではリアルタイムに臓器内部・背部の情報を取得可能な超音波診断装置を用い,超音波像と腹腔鏡像とを重畳表示することで術者が容易に臓器内部・背部情報を認識可能なシステムを開発した.【方法】開発システムではステレオ腹腔鏡および三次元超音波プローブにより取得した画像より対象臓器表面形状を構築し,これら臓器表面形状情報を揃えることで腹腔鏡像と超音波像の位置合わせを行う.この時,腹腔鏡像と超音波像を同時に取得することから,両者間において対象臓器の変形や移動を考慮する必要はない.そのため位置合わせにおける座標変換パラメータ算出には剛体変換パラメータを算出可能な ICP... [Show full abstract]
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      Actes: http://liris.cnrs.fr/publis/?id=4183
      December 1989 · IEEE Transactions on Information Theory · Impact Factor: 2.33
        It is shown that all extremal codes are homogeneous. This implies that each punctured code of an extremal code has the same weight distribution, which can be calculated directly from the weight distribution of the parent extremal code
        October 1998 · IEICE Transactions on Fundamentals of Electronics Communications and Computer Sciences · Impact Factor: 0.23
          In this paper, we study unequal error protection (UEP) capabilities of punctured convolutional codes. For constructing the good UEP convolutional codes, the conditional weight distributions of UEP convolutional codes are defined and evaluated. The conditional weight distributions are computed by using the transfer functions of time-varying trellis structures of punctured convolutional codes.... [Show full abstract]
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