Effects of Ultrasound Section-Thickness on Brachytherapy Needle Tip Localization Error

Abstract. Purpose: Ultrasound section-thickness is the out-of-plane beamwidth causing major roles in creating image artifacts normally appearing around the anechoic areas. These artifacts can introduce errors in localizing the needle tips during any ultrasound-guided procedure. To study how section-thickness and imaging parameters can affect observing and localizing needle tips, we have conducted a typical calibration setup experiment. Method: Multiple needles were inserted orthogonal to the axial image plane, at various distances from the transducer. The experiment was conducted on a brachytherapy stepper for a curvilinear transrectal-ultrasound probe. Result: Experiments demonstrated that the imaging parameters have direct impacts on observing needle tips at different axial locations. They suggest specific settings to minimize the imaging artifacts. Conclusion: The ultrasound section-thickness and side lobes could result in misjudgment of needle insertion depth in an ultrasound-guided procedure. A beam profile could assist in considering the likelihood of position errors, when the effects of side lobes are minimized

New perspectives for eye-sparing treatment strategies in primary uveal melanoma

Uveal melanoma is the most common intraocular malignancy and arises from melanocytes in the choroid, ciliary body, or iris. The current eye-sparing treatment options include surgical treatment, plaque brachytherapy, proton beam radiotherapy, stereotactic photon radiotherapy, or photodynamic therapy. However, the efficacy of these methods is still unsatisfactory. This article reviews several possible new treatment options and their potential advantages in treating localized uveal melanoma. These methods may be based on the physical destruction of the cancerous cells by applying ultrasounds. Two examples of such an approach are High-Intensity Focused Ultrasound (HIFU)—a promising technology of thermal destruction of solid tumors located deep under the skin and sonodynamic therapy (SDT) that induces reactive oxygen species. Another approach may be based on improving the penetration of anti-cancer agents into UM cells. The most promising technologies from this group are based on enhancing drug delivery by applying electric current. One such approach is called transcorneal iontophoresis and has already been shown to increase the local concentration of several different therapeutics. Another technique, electrically enhanced chemotherapy, may promote drug delivery from the intercellular space to cells. Finally, new advanced nanoparticles are developed to combine diagnostic imaging and therapy (i.e., theranostics). However, development. these methods More are mostly advanced at an and early targeted stage of preclinical development. studies More and advanced clinical trials and targeted would be preclinical needed to studies introduce and some clinical of trials these would techniques be needed to routine to introduce clinical practice. some of these techniques to routine clinical practice

Intermediate risk endometrial cancer- A heterogeneous clinical entity

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Obstetricia y Ginecología. Fecha de lectura: 17-03-202

Heating technology for malignant tumors: a review

The therapeutic application of heat is very effective in cancer treatment. Both hyperthermia, i.e., heating to 39-45 degrees C to induce sensitization to radiotherapy and chemotherapy, and thermal ablation, where temperatures beyond 50 degrees C destroy tumor cells directly are frequently applied in the clinic. Achievement of an effective treatment requires high quality heating equipment, precise thermal dosimetry, and adequate quality assurance. Several types of devices, antennas and heating or power delivery systems have been proposed and developed in recent decades. These vary considerably in technique, heating depth, ability to focus, and in the size of the heating focus. Clinically used heating techniques involve electromagnetic and ultrasonic heating, hyperthermic perfusion and conductive heating. Depending on clinical objectives and available technology, thermal therapies can be subdivided into three broad categories: local, locoregional, or whole body heating. Clinically used local heating techniques include interstitial hyperthermia and ablation, high intensity focused ultrasound (HIFU), scanned focused ultrasound (SFUS), electroporation, nanoparticle heating, intraluminal heating and superficial heating. Locoregional heating techniques include phased array systems, capacitive systems and isolated perfusion. Whole body techniques focus on prevention of heat loss supplemented with energy deposition in the body, e.g., by infrared radiation. This review presents an overview of clinical hyperthermia and ablation devices used for local, locoregional, and whole body therapy. Proven and experimental clinical applications of thermal ablation and hyperthermia are listed. Methods for temperature measurement and the role of treatment planning to control treatments are discussed briefly, as well as future perspectives for heating technology for the treatment of tumors

Tactile Sensing System for Lung Tumour Localization during Minimally Invasive Surgery

Video-assisted thoracoscopie surgery (VATS) is becoming a prevalent method for lung cancer treatment. However, VATS suffers from the inability to accurately relay haptic information to the surgeon, often making tumour localization difficult. This limitation was addressed by the design of a tactile sensing system (TSS) consisting of a probe with a tactile sensor and interfacing visualization software. In this thesis, TSS performance was tested to determine the feasibility of implementing the system in VATS. This was accomplished through a series of ex vivo experiments in which the tactile sensor was calibrated and the visualization software was modified to provide haptic information visually to the user, and TSS performance was compared using human and robot palpation methods, and conventional VATS instruments. It was concluded that the device offers the possibility of providing to the surgeon the haptic information lost during surgery, thereby mitigating one of the current limitations of VATS

Retinoblastoma

Retinoblastoma constitutes a global disease that burdens many families all over the world. This book highlights the essential basic information needed by every ophthalmologist and covers all aspects of this tumor: history, genetics, epidemiology, clinical features, diagnosis, imaging, management, and prognosis. The book includes basic knowledge, but is also designed to discuss current treatment modalities showing improved survival compared to the past. A whole chapter is dedicated to histopathological features and the American Joint Commission on Cancer staging system, with the aim of having it internationally used in all countries to improve outcomes and for research purposes. Readers will find the book enjoyable, comprehensive, and easy to understand

Endometrial carcinoma; can biomarkers aid in the prediction of aggressive disease? A study with focus on preoperative tumour markers

Background: Although endometrial cancer in general has a good prognosis, 15-20% recurs. Surgery is the main treatment with lymph node sampling increasingly advocated as compulsory for adequate staging. In metastatic disease, there is limited effect from systemic therapies including chemotherapy or antihormonal treatment. No other targeted therapies are yet available in a routine clinical setting. To improve and individualise therapy for this patient group, improved tools for identification of highrisk patients, to tailor surgery in particular, and identification of targetable molecular alterations for development of more effective systemic therapies, are urgently needed. Several biomarkers including hormone receptor status, TP53 and Stathmin expression have been found to be of prognostic importance in retrospective studies. The PI3Kinase signalling pathway is over-expressed in aggressive endometrial carcinomas and PI3kinase inhibitors are entering clinical trials for treatment of metastatic disease. Main objectives: The main objective was to evaluate if biomarkers, particularly examined in a preoperative setting, could identify aggressive endometrial carcinomas, especially those with lymph node metastasis. An additional aim was to evaluate immunohistochemical markers potentially applicable as markers for response to antihormonal therapy and PI3Kinase-inhibitors. Also, we wanted to study changes in treatment strategy in relation to survival for endometrial carcinoma patients during a 30-year period in a population based setting. Materials and methods: To evaluate potential biomarkers related to PI3Kinase signalling, a population based cohort was investigated for immunohistochemical expression of AKT, Phospho-AKT and Stathmin in hysterectomy specimens. These markers were also related to level of PI3Kinase signalling based on mRNA expression score in a prospective series of 76 patients (Paper I). The prospective international multicenter study MoMaTEC; Molecular Markers in Treatment of Endometrial Cancer, recruited clinical data, tissue and blood samples from 1192 endometrial cancer patients treated at 10 different centres during 2001-2010. Preoperative curettage specimens and blood samples have been investigated for expression of a panel of potential biomarkers; Stathmin, Estrogen Receptor (ER), Progesterone Receptor (PR), TP53 and GDF-15 (Paper II, III and IV). Changes in clinicopathological features and treatment were related to survival in a population based cohort of endometrial cancer patients from Hordaland County, Norway over the last 30 years (Paper V). Results: Stathmin overexpression in hysterectomy specimens was strongly correlated with characteristics for aggressive disease and poor survival. PI3Kinase signalling activation was significantly associated with overexpression of Stathmin. Neither AKT nor phospho-AKT expression showed any significant correlations with clinicopathological factors nor PI3Kinase signalling levels (Paper I). Overexpression of Stathmin validated to be correlated with aggressive disease in the large prospective multicentre setting (Paper II). Stathmin staining in curettage specimens was an independent predictor of lymph node metastases and overexpression of Stathmin estimated in curettage and hysterectomy specimens were both independent predictors of poor survival. High preoperative plasma GDF-15 level was significantly associated with aggressive disease. Adjusting for age and histological risk factors detected in preoperative biopsies, plasma GDF-15 independently predicted risk of lymph node metastasis. GDF-15 level also independently predicted poor prognosis (Paper III). Pathologic expression of ER, PR and TP53 in preoperative curettage specimen correlated significantly with high age at diagnosis, high FIGO stage, nonendometrioid histology, high grade, metastatic nodes and poor prognosis in a large prospective multicenter setting. Double negative ER-PR independently predicted lymph node metastasis and poor survival. Even for the most favourable group of lymph node negative endometrioid tumours, ER-PR negative status influenced survival independent of tumour grade (Paper IV). The number of endometrial cancer patients from Hordaland County increased significantly from 1981 through 2010 (Paper V), with a simultaneous increase in body mass index and decrease in disease stage at diagnosis. Routinely performed pelvic lymph node sampling increased, adjuvant radiotherapy was reduced and survival increased significantly during the same period. Conclusions: Stathmin immunohistochemical staining is superior to AKT and phospho-AKT staining in detecting PI3Kinase signalling activation and endometrial carcinomas with poor outcome (Paper I). Stathmin staining has been validated to identify endometrial carcinomas with aggressive clinic-pathological features in a large multicenter setting. Immunohistochemical staining for Stathmin in preoperative biopsies (curettage) independently predicts lymph node metastasis and poor survival (Paper II). Plasma GDF-15 has been documented as elevated in two independent patient cohorts of endometrial cancer patients compared to controls. High preoperative GDF-15 plasma level was significantly correlated with aggressive subtypes and a significant and independent predictor for lymph node metastasis and poor survival (Paper III). Double negative hormone receptor status (ER and PR negative) in preoperative endometrial cancer curettage has been validated to identify patients with poor prognosis in a prospective multicenter setting. ER-PR status independently predicts lymph node metastasis (Paper IV). During the 30-year period 1981 through 2010, a reduction in adjuvant radiotherapy and increase in routine pelvic lymphadenectomy and curative surgery with advanced disease, are associated with improved disease-specific- and overall survival in a population-based study of endometrial carcinoma patients with steadily increasing body mass index (Paper V)

Intravascular Ultrasound

Intravascular ultrasound (IVUS) is a cardiovascular imaging technology using a specially designed catheter with a miniaturized ultrasound probe for the assessment of vascular anatomy with detailed visualization of arterial layers. Over the past two decades, this technology has developed into an indispensable tool for research and clinical practice in cardiovascular medicine, offering the opportunity to gather diagnostic information about the process of atherosclerosis in vivo, and to directly observe the effects of various interventions on the plaque and arterial wall. This book aims to give a comprehensive overview of this rapidly evolving technique from basic principles and instrumentation to research and clinical applications with future perspectives