Rodríguez O, Chong-Quero JE, Leija L, Vera A, Otero JA, Rodríguez-Ramos R, Bravo-Castillero J

Language: Spanish
References: 23
Page: 16-22
PDF size: 156.93 Kb.

ABSTRACT

The design of ultrasound transducer for therapy applications is generally made with the purpose of maximizing its response to the electric stimulation. However, the drifts introduced by the dispersion and the temperature effects in the parameters of the elements that conform the generating system of ultrasonic waves, should be considered. With this purpose different approaches have been suggested in the literature. Among them is the use of piezocomposite materials of low losses for the fabrication of the transducer. In this way it is possible to increase the bandwidth of the transmission transfer function (TTF) of the transducer, resulting in a wider tolerance to the mentioned drifts. Additionally, a more uniform ultrasound radiation field is achieved which is fundamental in many therapy applications. This work presents a new approach for the optimization of the TTF of therapy transducers, where the active material is a piezocomposite of 2-2 structure. The study considers the homogenized characteristics of the transducer in function of its volumetric fraction and the interrelation of these parameters with the electric stimulation output stage by means of its internal impedance Rg. The obtained results suggest a relationship inversely proportional of the optimal volumetric fraction of the piezocomposite and the impedance Rg, for a maximum of the TTF.

REFERENCES

1. Pigozzi F, Moneta MR, Giombini A, Giannini S, Cesare D, Fagnani F, Mariani PP. Low-intensity pulsed ultrasound in the conservative treatment of pseudoarthrosis. Sports Med Phys Fitness 2004; 44(2): 173-8.

2. Bly NN, McKenzie A, Wong T, West T, Hunt TK. Incisional wound healing: a controlled study of low and high ultrasound. J Orthop Sports Phys Ther 1993; 18(5): 619-28.

3. Tachibana K. Emerging technologies in therapeutic ultrasound: thermal ablation to gene delivery. Hum Cell 2004; 7(1): 7-15.

4. Young SR, Dayson M. The effect of therapeutic ultrasound on angiogenesis. Ultrasound Med Biol 1990; 16: 261-9, 1990.

5. Duarte LR. The stimulation of bone growth by ultrasound. Arch Orthop Trauma Surg 1983; 101: 153-59.

6. Heckman JD, Ryaby JP, McCabe J, Frey JJ, Kilcoyne RF. Acceleration of tibia fracture-healing by non-invasive, low intensity pulsed ultrasound. J Bone Joint Surg [Am] 1994; 76: 26-34.

7. Klug W, Franke WG, Knoch HG. Scintigraphic control of bone-fracture healing under ultrasonic stimulation: an animal experimental study. Eur J Nucl Med 1986; 11: 496-7W.

8. Rodríguez ROR, Monreal R, Chong-Quero JE. Ultrasonido de baja intensidad para el tratamiento de fracturas óseas con retardo en la curación. Revista Mexicana de Ingeniería Biomédica 2005; 25(1): 52-56.

9. Lamberti N, Caliano G, Iula A, Pappalardo M. A New approach for the design of ultrasonotherapy transducers. IEEE Trans Ultrason, Ferroelect, Freq Cont, 1997; 44(1): 77-84.

10. Berlincourt DA, Curran DR, Jaffe H. Piezoelectric piezomagnetic materials and their function in transducers. In Physical Acoustics, Principles and Methods, Ed. W.P. Mason. Academia Press, New York. 1964; 1(A): 169-270.

11. Turó A, Salazar J, Chávez JA, Ortega JA, García MJ. Performance improvement of ultrasound therapy equipment by modifying the classical transducer design. IEE Pro-Sci Means Technol, 1999; 146(2): 9.

12. Geng X, Ritter TA, Shung KK. 1-3 Piezoelectric Composites for High Power Ultrasonic Transducer Applications. IEEE Proceeding 1999: 1191-1194.

13. Kluiwstra JU, McGough RJ, Cain CA. Therapeutic ultrasound phased arrays: practical consideration and design strategies. IEEE Proceeding 1996: 177-1180.

14. Moreno E, González G, Leija L, Rodríguez O, Castillo M, Fuentes M. Performance analysis of ultrasonotherapy transducer with contact detection. IEEE Trans Ultrason Ferroelectr Freq Control 2003; 50(6): 743-47.

15. Rodríguez OR, Hernández JA, Rodríguez-Ramos R, Castillero JB. Improved low-intensity ultrasound therapy transducer design by means of piezocomposites. Proceedings of the Ninth Annual International Conference on Composites Engineering (ICCE/9), San Diego, California, 2002: 667-668.

16. Chapelon JY, Cathignol D, Cain C, Ebbini E, Kluiwstra JU, Sapozhnikov OA, Fleury G, Berriet R, Chupin L, Guey JL. New piezoelectric transducers for therapeutic ultrasound. Ultrasound Med Biol 2000; 26(1): 153-9.

17. Esnault O, Franc B, Monteil JP, Chapelon JY. High-intensity focused ultrasound for localized thyroid-tissue ablation: preliminary experimental animal study. Thyroid 2004; 14(12): 1072-6.

18. Sferruzza JP, Birer A, Chavrier F, Cathignol D. Damping, amplitude, aging tests of stacked transducers for shock wave generation. IEEE Trans Ultrason Ferroelectr Freq Control. 2002; 49(10): 1453-60.

19. Castillero JB, Otero JA, Rodríguez-Ramos RR, Bourgent A. Asymtotic homogenization of laminated piezocomposite material. Int J Solids Structure 1998; 35(5-6): 537-4.

20. Mason WP. Electromechanical Transducers and Wave Filters. Princeton, NJ: Van Nostrand, 1948.

21. Krimholtz [2] R, Leedom DA, Matthaei GL. New equivalent circuit for elementary piezoelectric transducers. Electron. Lett., 1970; 6(13): 398-399.

22. Redwood [3] M. Transient performance of a piezoelectric transducer. J Acoust Soc Am 1961; 33(4): 527-536.

23. Morris[4] SA, Hutchens CG. Implementation of Mason’s model on circuit analysis programs. IEEE Trans. Ultrason., Ferroelect., Freq. Contr., 1986; 33(3): 295-298.