Chapters authored
Medical Application of Nonwoven Fabrics - Intra-abdominal Spacers for Particle Therapy
The authors aimed to introduce a medical application for nonwoven fabric as spacers in particle therapy. Particle therapy, exhibiting more focused effects on target tissues, has emerged as a promising treatment modality. However, close proximity of tumor tissue and adjacent organs makes delivery of curative doses to the tumor difficult because severe radiation morbidities might occur. A method using surgically placed GORE-TEX sheets as a spacer has been reported. Although this method provides for separation of adjacent organs, the material is not resorbed. To overcome these anatomical and therapeutic difficulties, and to deliver effective radiation doses to treat upper abdominal tumors, we have developed a nonwoven fabric spacer composed of bioabsorbable suture material. The absorbable polyglycolic acid (PGA) spacer had water-equivalent, biocompatible, and thickness-retaining properties. Although further evaluation is warranted in a clinical setting, the PGA spacer may be effective to block particle beams and to separate normal tissues from the radiation field. These findings suggest that the nonwoven-fabric PGA spacer might become a useful device in particle therapy.
Part of the book: Non-woven Fabrics
A Comparison of Physical vs. Nonphysical Wedge Modalities in Radiotherapy
This chapter discusses the clinical application and implementation of wedge techniques in radiation therapy. Coverage of the target region with a curative dose is critical for treating several cancer types; to that end, wedge filters are commonly used to improve dose uniformity to the target volume. Initially, wedges designed for this purpose were physical and were made of high-density materials such as lead or steel. Subsequently, nonphysical wedges were introduced; these improved the dose uniformity using computer systems in lieu of physical materials. As wedge systems evolve, however, they each continue to have their advantages and disadvantages. When using physical wedges, it is difficult to control the generation of secondary radiation resulting from the collision of the radiation beam with the wedge body; conversely, nonphysical wedges do not create any secondary radiation because there is no physical interference with the beam. On the other hand, nonphysical wedges are less suitable for treating moving tumors, such as those in the lung, and physical wedges have better dose coverage to the target volume than nonphysical wedges. This chapter aims to guide decision-making regarding the choice of wedge types in various clinical situations.
Part of the book: Radiotherapy