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Attenuation and de-focusing during high-intensity focused ultrasound therapy through peri-nephric fat.
- Source :
-
Ultrasound in medicine & biology [Ultrasound Med Biol] 2013 Oct; Vol. 39 (10), pp. 1785-93. Date of Electronic Publication: 2013 Aug 09. - Publication Year :
- 2013
-
Abstract
- High-intensity focused ultrasound (HIFU) is an attractive therapy for kidney cancer, but its efficacy can be limited by heat deposition in the pre-focal tissues, notably in fat around the kidney (peri-nephric fat), the acoustic properties of which have not been well characterized. Measurements of attenuation were made using a modified insertion-loss technique on fresh, unfixed peri-nephric fat obtained from patients undergoing kidney surgery for cancer. The de-focusing effect of changing the position of the fat layers was also investigated using fresh subcutaneous fat from euthanized pigs. The mean attenuation of human peri-nephric fat was found to be 11.9 ± 0.9 Np/m (n = 10) at 0.8 MHz, the frequency typically used for HIFU ablation of kidney tumors, with a frequency dependence of f(1.2). A typical 2- to 4-cm thickness of peri-nephric fat would result in a de-rated intensity of 3% - 62% at 0.8 MHz compared with a hypothetical patient with no peri-nephric fat. Through the use of freshly excised porcine subcutaneous fat, the presence of fat 100 mm in front of the focus was found to have a de-focusing effect of approximately 1 mm in both transverse directions, which corresponds to a full HIFU beam width off-target. Peri-nephric fat may significantly affect both the intensity and accuracy of HIFU fields used for the ablation of kidney cancer.<br /> (2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved)
- Subjects :
- Adipose Tissue surgery
Animals
High-Energy Shock Waves
Humans
In Vitro Techniques
Kidney surgery
Radiation Dosage
Scattering, Radiation
Swine
Adipose Tissue physiopathology
Adipose Tissue radiation effects
High-Intensity Focused Ultrasound Ablation methods
Kidney physiopathology
Kidney radiation effects
Subjects
Details
- Language :
- English
- ISSN :
- 1879-291X
- Volume :
- 39
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Ultrasound in medicine & biology
- Publication Type :
- Academic Journal
- Accession number :
- 23932273
- Full Text :
- https://doi.org/10.1016/j.ultrasmedbio.2013.04.010