Investigation into the thermal distribution of microwave helical antennas designed for the treatment of Barrett's oesophagus
| Autor: | J W Reeves, R.J. Collier, Malcolm Birch, K. Munro |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Materials science
Hot Temperature Coaxial cable Imaging phantom Epithelium law.invention chemistry.chemical_compound Barrett Esophagus Optics law Humans Radiology Nuclear Medicine and imaging Penetration depth Microwaves Polytetrafluoroethylene Computer Science::Information Theory Radiological and Ultrasound Technology Radiotherapy business.industry Phantoms Imaging Astrophysics::Instrumentation and Methods for Astrophysics Temperature Equipment Design Conductor chemistry Electromagnetic coil Antenna (radio) business Microwave |
| Zdroj: | Physics in medicine and biology. 47(19) |
| ISSN: | 0031-9155 |
| Popis: | A set of helical microwave antennas was designed to investigate their potential use in thermal therapy of Barrett's oesophagus. The antennas had a diameter of up to 3.3 mm and various lengths between 20 and 37 mm; these were designed to operate at 915 MHz. Sets of polytetrafluoroethylene (PTFE) formers were constructed to improve the repeatability and reproducibility of the helix manufacture. Small diameter copper wire was wound over the formers and connected to the coaxial cable at the inner and outer conductor junctions. The power deposition profiles of the antennas were measured in a muscle-equivalent phantom using an infrared camera. The effects of antenna length and coil spacing were characterized. It was observed that uniform temperature profiles along the antenna length were achieved with a length of wire of 99 mm ± 2 mm. The effective heating length (length of the antenna that exhibits >50% of the maximum temperature rise) was comparable to the antenna length. The radial penetration depth of 50% of the antenna surface temperature for the optimum 20 mm antenna was 2.5 mm from the antenna outer surface. |
| Databáze: | OpenAIRE |
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