The heating pattern of a transurethral radio frequency (RF) applicator and its induced steady-state temperature field in the prostate during transurethral hyperthermia treatment were investigated in this study. The specific absorption rate (SAR) of the electromagnetic energy was first quantified in a tissue-equivalent gel phantom. It was used in conjunction with the Pennes bioheat transfer equation to model the steady-state temperature field in prostate during the treatment. Theoretical predictions were compared to in vivo temperature measurements in the canine prostate and good agreement was found to validate the model. The prostatic tissue temperature rise and its relation to the effect of blood perfusion were analyzed. Blood perfusion is found to be an important factor for removal of heat especially at the higher RF heating level. To achieve a temperature above 44°C within 10 percent of the prostatic tissue volume, the minimum RF power required ranges from 5.5 W to 36.4 W depending on the local blood perfusion rate (ω = 0.2−1.5 ml/gm/min). The corresponding histological results from the treatment suggest that to obtain better treatment results, either higher RF power level or longer treatment time (>180 minutes) is necessary. This is consistent with the predictions from the theoretical model developed in this study.
Issue Section:
Technical Papers
1.
Anderson
L.
Dahn
L.
Nelson
C.
Norgren
A.
1967
, “Method for Measuring Prostatic Blood Flow With Xenon133 in the Dog
,” Invest. Urol.
, Vol. 5
, pp. 140
–148
.2.
Arkin
H.
Holmes
K. R.
Chen
M. M.
Bottje
W. G.
1986
, “Thermal Pulse Decay Method for Simultaneous Measurement of Local Thermal Conductivity and Blood Perfusion: A Theoretical Analysis
,” ASME JOURNAL OF BIOMECHANICAL ENGINEERING
, Vol. 108
, pp. 208
–214
.3.
Astrahan
M. A.
Sapozink
M. D.
Cohen
D.
Luxton
G.
Kampp
T. D.
Boyd
S.
Petrovich
Z.
1989
, “Microwave Applicator for Transurethral Hyperthermia of Benign Prostatic Hyperplasia
,” Int. J. Hyperthermia
, Vol. 5
, pp. 283
–296
.4.
Astrahan
M. A.
Imanaka
K.
Jozsef
G.
Ameyes
F.
Baert
L.
Sapozink
M. D.
Boyd
S.
Petrovich
Z.
1991
, “Heating Characteristics of a Helical Microwave Applicator for Transurethral Hyperthermia of Benign Prostatic Hyperplasia
,” Int. J. Hyperthermia
, Vol. 7
, pp. 141
–155
.5.
Baert
L.
Ameye
F.
Willemen
P.
Vandenhove
J.
Lauweryns
J.
Astrahan
M. A.
Petrovich
Z.
1990
, “Transurethral Microwave Hyperthermia for Benign Prostatic Hyperplasia: Preliminary Clinical and Pathological Results
,” Journal of Urology
, Vol. 144
, pp. 1383
–1387
.6.
Baert
L.
Ameye
F.
Pike
M. C.
Willemen
P.
Astrahan
M. A.
Petrovich
Z.
1992
, “Transurethral Hyperthermia for Benign Prostatic Hyperplasia Patients With Retention
,” Journal of Urology
, Vol. 147
, pp. 1558
–1561
.7.
Baert
L.
Ameye
F.
Astrahan
M.
Petrovich
Z.
1993
, “Transurethral Microwave Hyperthermia for Benign Prostatic Hyperplasia: the Leuven Clinical Experience
,” J. Endourology
, Vol. 7
, pp. 61
–69
.8.
Bdesha
A. S.
Bunce
C. J.
Kelleher
J. P.
Shell
M. E.
Vukusic
J.
Witherow
R. O’N.
1993
, “Transurethral Microwave Treatment for Benign Prostatic Hypertrophy: a Randomized Controlled Clinical Trial
,” British Medicine Journal
, Vol. 306
, pp. 1293
–1296
.9.
Bdesha
A. S.
Bunce
C. J.
Snell
M. E.
Witherow
R. O’N.
1994
, “A Sham Controlled Trial of Transurethral Microwave Therapy With Subsequent Treatment of the Control Group
,” Journal of Urology
, Vol. 152
, pp. 453
–458
.10.
Bini
M. G.
Ignesti
A.
Millanta
L.
Olmi
R.
Rubino
N.
Vanni
R.
1984
, “The Polyacrylamide as a Phantom Material for Electromagnetic Hyperthermia Studies
,” IEEE Trans. Biomed. Eng.
, Vol. 31
(3
), pp. 317
–322
.11.
Chato, J. C., 1991, “Fundamentals of Bioheat Transfer,” in: Thermal Dosimetry and Treatment Planning, M. Gautherie, ed., Springer-Verlag.
12.
Chowdhury
D. Q.
Hill
S. C.
1991
, “Numerical Optimization of 3-D SAR Distributions in Cylindrical Models for Electromagnetic Hyperthermia
,” IEEE Transactions on Biomedical Engineering
, Vol. 38
, pp. 1246
–1255
.13.
Dewey
W. C.
1994
, “Arrhenius Relationships From the Molecule and Cell to the Clinic
,” Int. J. Hyperthermia
, Vol. 10
, pp. 457
–483
.14.
Gentili
G. B.
Gori
F.
Leoncini
M.
1991
, “Electromagnetic and Thermal Models of a Water-Cooled Dipole Radiating in a Biological Tissue
,” IEEE Transactions on Biomedical Engineering
, Vol. 38
, pp. 98
–103
.15.
Gentili
G. B.
Leoncin
M.
Trembly
B. S.
Schweizer
S. E.
1995
, “FDTD Electromagnetic and Thermal Analysis of Interstitial Hyperthermic Applicators
,” IEEE Transactions on Biomedical Engineering
, Vol. 42
(10
), pp. 973
–980
.16.
Hirai
M.
1992
, “Basic and Clinical Studies of Local Hyperthermia for Prostate Cancer
,” Jap. J. Urol.
, Vol. 5
, pp. 597
–604
.17.
Homma
Y.
Aso
Y.
1993
, “Transurethral Microwave Thermotherapy for Benign Prostatic Hyperplasia: A 2-year Follow-up Study
,” Journal of Endourology
, Vol. 7
, pp. 261
–265
.18.
Jones
K. M.
Mechling
J. A.
Trembly
B. S.
Strohbehn
J. W.
1988
, “SAR Distributions for 915 MHz Interstitial Microwave Antennas Used in Hyperthermia for Cancer Therapy
,” IEEE Transactions on Biomedical Engineering
, Vol. 35
, pp. 851
–857
.19.
Langley Research Center, Hampton, Virgina, 1992, “Tissue-Simulating Gel for Medical Research: the Nonhardening, Translucent Gel More Nearly Simulates Soft Human or Animal Tissue,” NASA Tech. Briefs, Jan., p. 80.
20.
Larson
T. R.
Bostwick
D. G.
Corica
A.
1996
, “Temperature-Correlated Histopathologic Changes Following Microwave Thermoablation of Obstructive Tissue in Patients With Benign Prostatic Hyperplasia
,” Urology
, Vol. 47
, pp. 463
–469
.21.
Larson
T. R.
Collins
J. M.
1995
a, “An Accurate Technique for Detailed Prostatic Interstitial Temperature-Mapping in Patients Receiving Microwave Thermal Treatment
,” Journal of Endourology
, Vol. 9
, pp. 339
–347
.22.
Larson
T. R.
Collins
J. M.
1995
b, “Increased Prostatic Blood Flow in Response to Microwave Thermal Treatment: Preliminary Findings in Two Patients With Benign Prostatic Hyperplasia
,” Urology
, Vol. 46
, pp. 584
–590
.23.
Magin
R. L.
Fridd
C. W.
Bonfiglio
T. A.
Linke
C. A.
1980
, “Thermal Destruction of the Canine Prostate by High Intensity Microwaves
,” J. Surg. Res.
, Vol. 29
, pp. 265
–275
.24.
Marteinsson
V. T.
Due
J.
1994
, “Transurethral Microwave Thermotherapy for Uncomplicated Benign Prostatic Hyperplasia
,” Scand. J. Urol.
, Vol. 28
, pp. 83
–89
.25.
Martin
G. T.
Haddad
M. G.
Cravalho
E. G.
Bowman
H. F.
1992
, “Thermal Model for the Local Microwave Hyperthermia Treatment of Benign Prostatic Hyperplasia
,” IEEE Transactions on Biomedical Engineering
, Vol. 39
, pp. 836
–844
.26.
Mechling
J. A.
Strohbehn
J. W.
1986
, “A Theoretical Comparison of the Temperature Distributions Produced by Three Interstitial Hyperthermia Systems
,” Int. J. Radiation Oncology Biol. Phys.
, Vol. 12
, pp. 2137
–2149
.27.
Nau
W. H.
Pou
N. A.
Roselli
R. J.
Milam
D. F.
1996
, “Quantitative Measurements of Prostatic Blood Flow During Laser Irradiation Using Radiolabeled Microsphere
,” Annals of Biomedical Engineering
, Vol. 24
(suppl. 1
), pp. s–24
24
.28.
Nissenkom
I.
Meshorer
A.
1993
, “Temperature Measurements and Histology of the Canine Prostate During Transurethral Hyperthermia
,” Journal of Urology
, Vol. 149
, pp. 1613
–1616
.29.
Patel
U. H.
Babbs
C. F.
1993
, “Development of a Rapidly Computable Descriptor of Prostate Tissue Temperature during Transurethral Conductive Heat Therapy for Benign Prostate Hyperplasia
,” Medical and Biological Engineering and Computing
, Vol. 31
(5
), pp. 475
–481
.30.
Pennes
H. H.
1948
, “Analysis of Tissue and Arterial Blood Temperatures in the Resting Human Forearm
,” J. Appl. Physiol.
, Vol. 1
, pp. 93
–122
.31.
Rosette
J. J. M. C. H. de la
Froeling
F. M. J. A.
Debruyne
F. M. J.
1993
, “Clinical Results with Microwave Thermotherapy of Benign Prostatic Hyperplasia
,” Eur. Urology
, Vol. 23
(suppl. 1
), pp. 68
–71
.32.
Sapozink
M. D.
Boyd
S. D.
Astrahan
M. A.
Jozaef
G.
and Petrovich
Z.
1990
, “Transurethral Hyperthermia for Benign Prostatic Hyperplasia: Preliminary Clinical Results
,” Journal of Urology
, Vol. 143
, pp. 944
–955
.33.
Scheiblich
J.
Petrowicz
O.
1982
, “Radio Frequency-Induced Hyperthermia in the Prostate
,” Journal of Microwave Power
, Vol. 17
(3
), pp. 203
–209
.34.
Stoy
R. D.
Foster
K. R.
Schwan
H. P.
1982
, “Dielectric Properties of Mammalian Tissues From 0.1 to 100 MHz: a Summary of Recent Data
,” Phys. Med. Biol.
, Vol. 27
(4
), pp. 501
–513
.35.
Strohbehn
J. W.
1983
, “Temperature Distributions From Interstitial RF Electrode Hyperthermia Systems: Theoretical Predictions
,” Int. J. Radiation Oncology Biol. Phys.
, Vol. 9
, pp. 1655
–1667
.36.
Tompkins
D. T.
Vanderby
R.
Klein
S. A.
Beckman
W. A.
Steeves
R. A.
Frye
D. M.
Paliwal
B. R.
1994
, “Temperature-Dependent Versus Constant-Rate Blood Perfusion Modeling in Ferromagnetic Thermoseed Hyperthermia: Results With a Model of the Human Prostate
,” International Journal of Hyperthermia
, Vol. 10
, pp. 517
–536
.37.
Wong
T. Z.
Jonsson
E.
Hoopes
J. P.
Trembly
B. S.
Heaney
J. A.
Douple
E. B.
Coughlin
C. T.
1993
, “A Coaxial Microwave Applicator for Transurethral Hyperthermia of the Prostate
,” Prostate
, Vol. 22
, pp. 125
–138
.38.
Wonnell
T. L.
Stauffer
P. R.
Langberg
J. J.
1992
, “Evaluation of Microwave and Radio Frequency Catheter Ablation in a Myocardium-Equivalent Phantom Model
,” IEEE Trans. Biomed. Eng.
, Vol. 39
, pp. 1086
–1095
.39.
Xu
L. X.
Rudie
E.
Holmes
K. R.
1993
, “Transurethral Thermal Therapy (T3) for the Treatment of Benign Prostatic Hyperplasia (BPH) in the Canine: Analysis Using Pennes Bioheat Transfer
,” Adv. Bio. Heat & Mass Transfer
, ASME HTD-Vol. 268
, pp. 31
–35
.40.
Xu
L. X.
Zhu
L.
Holmes
K. R.
1998
, “Thermoregulation in the Canine Prostate During Transurethral Microwave Hyperthermia, Part II: Blood Flow Response
,” International Journal of Hyperthermia
, Vol. 14
, pp. 65
–73
.41.
Yuan
D. Y.
Valvano
J. W.
Rudie
E. N.
Xu
L. X.
2-D Finite Difference Modeling of Microwave Heating in the Prostate
,” Adv. Bio. Heat & Mass Transfer in Biotechnology
, ASME HTD-Vol. 322
, pp. 107
–115
.42.
Zhu
L.
Xu
L. X.
Yuan
D. Y.
Rudie
E. N.
1996
, “Electromagnetic (EM) Quantification of Microwave Antenna for the Transurethral Prostatic Thermotherapy
,” Advances in Heat and Mass Transfer in Biotechnology
, ASME HTD-Vol. 337
/BED-Vol. 34, pp. 17
–20
.43.
Zhu
L.
Xu
L. X.
Chencinski
N.
1998
, “Quantification of the 3-D Electromagnetic Power Absorption Rate in Tissue During Transurethral Prostatic Microwave Thermotherapy Using Heat Transfer Model
,” IEEE Trans. Biomedical Engineering
, Vol. 45
, pp. 1163
–1172
.
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