• Title/Summary/Keyword: Hyperthermia

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Array of Slot-Sleeve Antennas for Hyperthermia Therapy

  • Park Soo-Man;Lim Yeongseog
    • Journal of electromagnetic engineering and science
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    • v.5 no.3
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    • pp.126-131
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    • 2005
  • To increase the efficiency of an applicator during microwave hyperthermia therapy, first, the length from the antenna end to a slot is varied to get the optimal matching of the characteristic impedance at the frequency of 2.45 GHz. Using the electric and thermal constants of biological tissue, we compose a phantom to calculate temperature increment as well as the resonance characteristics and the SAR distributions. The proposed 3-slot sleeve antenna inserted in an applicator plays an effective role in increasing the therapy size in the view of heating performance as electromagnetic energy tends to concentrate on not feed point direction but treatment area. The SAR is then used in combination with a finite difference heat transfer equation to determine the temperature distribution. Also, in order to shorten treatment time and increase therapy size, a square-array structure is suggested and analyzed.

A Study on the RF and Microwave Hyperthermia System for Cancer Therapy (온열료법을 이용한 고주파 및 마이크로웨이브 암치료기에 관한 연구)

  • 유재병;박덕규;양성화;박민용;추성실;이상배
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.3
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    • pp.486-492
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    • 1987
  • This study is an attempt to review the theories about the RF and microwave hyperthermia and to get the practical implementation of hyperthermia system on the basic clinical experiments with agar phantoms and four patients. The frequencies of RF power are 8 MHz and 16 MHz, which are effective for the heating of deep-seated and superficial tumors, and microwave is 2.45 GHz, also suitable for the heating of superficial tumors. Even if the long-term effect of clinical applications were not investigated for human living body, it was observee that the RF and microwave hyperthermias are effective for many kinds of cancers in the fixed frequency ranges.

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A Study on the Hybrid Heater Composed of a Temperature Sensitive Ferrite with Low Permeability for Hyperthermia

  • Kim, Y.H.;Kang, H.K.;Shin, K.H.
    • Journal of Magnetics
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    • v.12 no.4
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    • pp.161-164
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    • 2007
  • Constant temperature regulation of a hybrid heater which is composed of a temperature sensitive ferrite with low permeability and a Cu tube is investigated for hyperthermia. The temperature sensitive ferrite is inserted into a Cu tube and its length and diameter are 10 mm and 3 mm. Below B=0.05 T, the measured temperature and the calculated one increased with the ratio of $B^{1/2}$ and agreed well with each other. Above B=0.05 T, the measured temperatures maintained constantly almost $50^{\circ}C{\pm}1.5^{\circ}C$ because of the influence of Curie temperature of the temperature sensitive ferrite. This result shows that the hybrid heater is able to regulate the temperature constantly at the rate of $50^{\circ}C{\pm}1.5^{\circ}C$.

Thermometry in Hyperthermia induced by Ultrasound A Phantom study (초음파를 이용한 온열료법시 온도분포에 관한 연구)

  • Park, Charn-Il;Koh, Kyeong-Whan;Ha, Sung-Whan
    • Radiation Oncology Journal
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    • v.2 no.1
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    • pp.21-23
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    • 1984
  • Temperature homogeniety and stationary temperature is the most important thermometric considerations for the clinical use of hyperthermia. A thermal mapping was done in a phantom with thermocouple during hyperthermia which was induced by 1.0MHz,$0.7\~0.8watts/cm^2$ ultrasound and unfocused 2.5cm-diameter transducer. The results were as follows 1. Effective heating range$(42.5^{|circ}C\pm0.5^{\circ}C)$ were obtained 3cm in width and 4cm in depth from surface of phantom and temperature distribution was relatively uniform. 2. There was little heating effect more than 2cm away from transducer axis and more than 5cm in depth. 3. There was hot spots(more than $43^{\circ}C$) in $2.0\pm0.5cm$ depth from transducer along tranducer axis.

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Thermosensitizing Effects of Amiloride and 4,4-Diisothiocyanatostilbene-2,2'-disulfonic Acid on FsaII Mouse Fibrosarcoma

  • Lee, Soo-Young
    • BMB Reports
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    • v.32 no.5
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    • pp.511-514
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    • 1999
  • Enhancement of the hyperthermia effect in FsaII fibrosarcoma of C3H mice in vivo by amiloride and 4,4- diisothiocyanatostilbene.2,2'-disulfonic acid (DIDS) was studied. Heating alone significantly increased the tumor lactic acid content and lowered the tumor energy levels, as indicated by the PCr and ATP contents which were measured using invasive chemical analysis. An i.p. injection of amiloride, DIDS, or amiloride combined with DIDS prior to heating further increased the lactic acid content and reduced the energy status in the tumors. Amiloride and DIDS may be useful in increasing the therapeutic efficacy of hyperthermia treatments by enhancing the reduction in tumor pH.

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Effects of Radiofrequency Induced Local Hyperthermia on Normal Canine Liver (라디오 파를 이용한 국소 온열치료 : 정상 개의 간에 미치는 영향)

  • Suh Chang Ok;Loh. John J.K.;Shin Hyun Soo;Lee Hyung Sik;Moon Sun Rock;Seong Jin Sil;Chu Sung Sil;Kim Gwi Eon;Han Eun Kyung;Park Chan Il
    • Radiation Oncology Journal
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    • v.9 no.1
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    • pp.37-45
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    • 1991
  • In order to assess the effects of radiofrequency-induced local hyperthermia on the normal liver, histopathologic findings and biochemical changes after localized hyperthermia in canine liver were studied. Hyperthermia was externally adminsitered using the Thermotron RF-8 (Yamamoto Vinyter Co., Japan; Capacitive type heating machine) with parallel opposed electrodes. Thirteen dogs were used and allocated into one control group (N=3) and two treatment groups according to the treatment temperature. Group I (N=5) was heated with $42.5\pm0.5^{\circ}C$ 30 minutes, and Group II (N=5) was heated with $45\pm0.5^{\circ}C$ for 15-30 minutes. Samples of liver tissue were obtained through a needle biopsy immediately after hyperthermia and T,14, and 28 days after treatment. Blood samples were obtained before treatment and W, 3,5, 7,14 and 28 days after treatment and examined for SGOT, SGPT and alkaline phosphatase. Although SGOT and SGPT were elevated after hyperthermia in both groups (three of five in each group), there was no liver cell necrosis or hyperthermia related mortality in Group 1. A hydropic swelling of hepatocytes was prominent histologic finding. Hyperthermia with $45^{\circ}C$ for 30 minutes was fatal and showed extensive liver cell necrosis. In conclusion, liverdamage dy heat of $42.5\pm0.5^{\circ}C$ for 30 minutes is reversible, and liver damage by heat of $45\pm0.5^{\circ}C$ for 30 minutes can be fatal or irreversible. However, these results cannot be applied directly to human trial. Therefore, in erder to apply hyperthermic treatment on human liver tumor safely, close obsewation of temperature with proper thermometry is mandatory. Hyperthermic treatment should be confined to the tumor area while sparing a normal liver as much as possible.

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An Experimental Study on the Effectiveness of Microwave Hyperthermia Combined with Radiation on the Small and Large Intestine in rats (흰쥐의 장조직에 X-선 조사와 마이크로파 온열요법의 효과에 관한 실험적 연구)

  • Ahn, Kyung-Sook;Lee, Kyung-Ja;Rhee, Chung-Sik
    • Radiation Oncology Journal
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    • v.5 no.2
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    • pp.83-95
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    • 1987
  • The synergistic effect of combining radiation therapy and hyperthermia kills significantly more cells than using either modality alone. The reason for enhanced cell killing from the combined treatment is that the two modalities are complementary. For histopathological exmination, 102 rats were divided into 4 groups as hyperthermia, radiation, hyperthermia combined with radiation and normal control groups. The effect of prior irradiation (6-15 Gy of X-ray) on the response of small and large bowel of rats to $40^{\circ}C-44^{\circ}C$ (for 30 minutes) microwave (2450 MHz) hyperthermia was investigated. The musculature of the small and large intestine remained intact and the circumference of the histological sections were not significantly altered by the heated at $43^{\circ}C$ for 30 minutes. Thermal enhancement ratios of normal tissue is 1.0 Thermal enhancement ratio was not increased in combination therapy by evaluation of histopathologic changes in small and large intestine.

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Biochemical Changes of Liver Function in Patients with Hepatocellular Carcinoma Following Radiotherapy and Hyperthermia (진행된 원발성 간암 환자에서 방사선 치료 및 온열 요법에 따른 간 기능의 변화)

  • Oh Young Taek;Seong Jinsil;Shin Hyun Soo;Kim Gwi Eon
    • Radiation Oncology Journal
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    • v.11 no.1
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    • pp.109-117
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    • 1993
  • To analyze biochemical changes of liver function following combined radiotherapy and hyperthermia, we reviewed retrospectively 37 patients with hepatocellular carcinoma treated with radiotherapy and hyperthermia between July 1988 and December 1990 at Department of Radiation Oncology, Yonsei University College of Medicine. Mean age was 52.7 years and male to female ratio was 11:1. The patients were classified as follows; to A and B group by Child's classification, to M and L group by irradiated volume, and subclassified into BM, BL, AM and AL group according to the combination of Child's classification and irradiated volume. Radiation dose to the primary tumor was 3060 cGy with daily 180 cGy, 5 fraction per week using 10 MV or 4 MV linear accelerator. Hyperthermia (Thermotron RF-8) was performed more than 4 times in all patients. Biochemical parameters including albumin (Alb), total bilirubin (T. Bil), aspartate aminotransferase (AST or SGOT), alanine aminotransferase (ALT or SGPT), and alkaline phosphatase (ALP) were regularly followed from 1 week before the treatment to 3 months after the treatment. The results are summerized as follows; 1) In all the patient, mean ALP level peaked at 1 month, decreased at 2 months, slightly increased at 3 months after the treatment. Mean SGOT and SGPT levels peaked at 1 month after the treatment. Mean T. Bil level increased continuously and highest at 3 months after the treatment. Mean Alb level did not show significant changes.; 2) Mean ALP level retured to normal level at 3 month after the treatment in A but increased in B group and the differences were statistically significant (p<0.01). Mean SGOT and SGPT levels peaked 1 month in A and 2 months after the treatment in B group. All the biochemical parameters did not show significant difference between M and L group. Mean ALP level increased at 3 months after the treatment in BM and BL groups and decreased in AM and AL groups. Mean SGOT level increased at 3 months after the treatment in BL groups.; 3) Hepatic failure occurred within 3 months after the treatment in 4 patients, all of whom were in BL group. It is suggested that pre-treatment liver function and irradiated volume influence biochemical changes of liver in patients with hepatocellular carcinoma following combined radiotherapy and hyperthermia, and this treatment modality appears generally to be safe but might cause hepatic failure particularly in patient with poor liver function and large treatment volume.

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Design and implementation of RF hyperthermia system for deep-seated cancer therapy. (심재성 암치료를 위한 RF hyperthermia system의 설계 및 제작)

  • Yoo, Jae-Hyoung;Park, Mi-Gnon
    • Proceedings of the KOSOMBE Conference
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    • v.1985 no.06
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    • pp.9-12
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    • 1985
  • This paper covers the design and implementation process of RF hypertermia system for cancer therapy. Among many hyperthermic methods, RF capacitive heating method is discussed because it can heat the deep-seated tumors selectively. The RF power oscillator and its applicators were designed and implemented. And the experiments were performed with agar phantom and dog to prove that the system can heat any depth selectively. And the electrical safety and appropriateness of clinical application was proved through the human living-body test.

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