The potential of time-multiplexed steering in phased array microwave hyperthermia for head and neck cancer treatment.

Clinical studies have shown that hyperthermia sensitizes tumor cells for conventional therapies. During phased-array microwave hyperthermia, an array of antennas is used to focus the electromagnetic waves at the target region. Selective heating, while preserving the healthy tissue, is a demanding challenge and currently patient specific pre-treatment planning is used to optimize the amplitudes and phases of the waves. In addition, when needed, this single optimal heat distribution is adapted using the simulations based on the feedback from thermo-sensors and the patient. In this paper, we hypothesize that sequential, i.e. 'time-multiplexed', application of multiple Pareto optimal heating patterns provides a better time-averaged treatment quality. To test the benefit of such a time-multiplexed approach, a multi-objective genetic algorithm was introduced to balance two objectives that both focus the specific absorption rate (SAR) delivered to the target region but differ in the suppressing of pre-defined hotspots. This step leads to two Pareto optimal distributions. These 'diverse' antenna settings are then applied sequentially and thermal simulations are used to evaluate the effectiveness of the time-multiplexed steering. The proposed technique is tested using treatment planning data of a representative dataset of five head and neck patients for the HYPERcollar3D. Steering dynamics are analysed and the time-multiplexed steering is compared to the current static solution used in the clinic, i.e. hotspot-target SAR quotient optimization using particle swarm optimization. Our results demonstrate that realistic steering periods of 10s suffice to stabilize temperatures within 0.04 °C and the ability to enhance target heating while reducing hotspots, i.e. 0.3 °C-1.2 °C improvement in T 50 while reducing hotspot temperatures by 0.6 °C-1.5 °C.

Performance of leading artifact removal algorithms assessed across microwave breast imaging prototype scan configurations.

Microwave imaging is a promising imaging modality for the detection of early-stage breast cancer. One of the most important signal processing components of microwave radar-based breast imaging is early-stage artifact removal. Several artifact removal algorithms have been reported in the literature. However, the neighbourhood-based skin subtraction and hybrid artifact removal algorithms have shown particularly promising results in different realistic 3D breast phantoms. For the first time in this paper, both algorithms have been evaluated and compared using the scan approaches of the most common microwave breast imaging prototype systems. The tests include 3D numerical as well as experimental breast phantoms scanned with hemispherical, cylindrical and adaptive scanning patterns. The efficacy of both algorithms has been evaluated across a range of appropriate performance metrics.

Differential Evolution Optimization of the SAR Distribution for Head and Neck Hyperthermia.

Hyperthermia is an emerging cancer treatment modality, which involves applying heat to the malignant tumor. The heating can be delivered using electromagnetic (EM) energy, mostly in the radiofrequency (RF) or microwave range. Accurate patient-specific hyperthermia treatment planning (HTP) is essential for effective and safe treatments, in particular, for deep and loco-regional hyperthermia. An important aspect of HTP is the ability to focus microwave energy into the tumor and reduce the occurrence of hot spots in healthy tissue. This paper presents a method for optimizing the specific absorption rate (SAR) distribution for the head and neck cancer hyperthermia treatment. The SAR quantifies the rate at which localized RF or microwave energy is absorbed by the biological tissue when exposed to an EM field. A differential evolution (DE) optimization algorithm is proposed in order to improve the SAR coverage of the target region. The efficacy of the proposed algorithm is demonstrated by testing with the Erasmus MC patient dataset. DE is compared to the particle swarm optimization (PSO) method, in terms of average performance and standard deviation and across various clinical metrics, such as the hot-spot-tumor SAR quotient (HTQ), treatment quantifiers, and temperature parameters. While hot spots in the SAR distribution remain a problem with current approaches, DE enhances focusing microwave energy absorption to the target region during hyperthermia treatment. In particular, DE offers improved performance compared to the PSO algorithm currently deployed in the clinic, reporting a range of improvement of HTQ standard deviation of between 40.1-96.8% across six patients.

Bringing managed care incentives to Medicare's fee-for-service sector.

The Health Care Financing Administration (HCFA) could work with eligible physician organizations to generate savings in total reimbursements for their Medicare patients. Medicare would continue to reimburse all providers according to standard payment policies and mechanisms, and beneficiaries would retain the freedom to choose providers. However, implementation of new financial incentives, based on meeting targets called Group-Specific Volume Performance Standards (GVPS), would encourage cost-effective service delivery patterns. HCFA could use new and existing data systems to monitor access, utilization patterns, cost outcomes and quality of care. In short, HCFA could manage providers, who, in turn, would manage their patients' care.

A novel optimized parallelization strategy to accelerate microwave tomography for breast cancer screening.

Microwave tomography has been proven to successfully reconstruct the dielectric profile of a human breast when used in breast imaging applications, thereby providing an alternative to other imaging modalities. However, the method suffers from high computational requirements which restrict its use in practical imaging systems. This paper presents a novel parallelization strategy to accelerate microwave tomography for reconstruction of the dielectric properties of the human breast. A Time Domain algorithm using this parallelization strategy has been validated and benchmarked against an optimized sequential implementation on a conventional high-end desktop Central Processing Unit (CPU), and a comparison of throughput is presented in this paper. The gain in computational throughput is shown to be significantly higher compared with the sequential implementation, ranging from a factor of 26 to 58, on imaging grid sizes of up to 25 cm square at 1 mm resolution.

The effects of lossy compression on diagnostically relevant seizure information in EEG signals.

This paper examines the effects of compression on EEG signals, in the context of automated detection of epileptic seizures. Specifically, it examines the use of lossy compression on EEG signals in order to reduce the amount of data which has to be transmitted or stored, while having as little impact as possible on the information in the signal relevant to diagnosing epileptic seizures. Two popular compression methods, JPEG2000 and SPIHT, were used. A range of compression levels was selected for both algorithms in order to compress the signals with varying degrees of loss. This compression was applied to the database of epileptiform data provided by the University of Freiburg, Germany. The real-time EEG analysis for event detection automated seizure detection system was used in place of a trained clinician for scoring the reconstructed data. Results demonstrate that compression by a factor of up to 120:1 can be achieved, with minimal loss in seizure detection performance as measured by the area under the receiver operating characteristic curve of the seizure detection system.

Suspected ketorolac toxicosis in a dog

Non-steroidal anti-inflammatory drugs (NSAIDs) also have analgesic and anti-pyretic properties. Ketorolac tromethamine (ketorolac) is a potent NSAID which is used mainly for its analgesic properties in humans. Ketorolac is also available as a registered veterinary pharmaceutical product in Trinidad. Off-label use of NSAIDs in dogs has been documented and is occasionally used in small animal practice in Trinidad. Six days after the treatment with ketorolac tablets (5 milligram) once daily for five days, a 20 kilogram (kg) mixed breed female dog was presented to the Veterinary Hospital, School of Veterinary Medicine, Trinidad. A grave prognosis was given based on the clinical signs of anorexia, hematemesis, very pale mucous membranes, melanoma and lateral recumbency. The animal was euthanised and submitted for necroscopy. Severe hemorrhage (140 millilitres) from gastric ulcerations, and multi-focal hepatic necrosis was found on necroscopy. Histopathology reinforced the hypothesis of ketorolac toxicosis causing gastric ulceration. Also noteworthy was a predominantly lymphoplasmacytic infiltrate accompanying a peri-acinar hepatic necrosis. Ketorolac is conjugated by the liver to an inactive metabolite and excreted by the kidney. Data from human and canine studies have consistently recorded gastric ulcerations as a side effect of this drug. Concurrent hepatic disease may have prolonged its duration of activity, thereby increasing the incidence and/or the severity of side effects. Contra-indications for the use of this drug in humans and animals include renal disease, cardiac disease, concurrent gastro-intestinal ulceration, dehydration and shock, but not hepatic disease/insufficiency (AU)