In capacitive heating, an air gap between a human body and a bolus often causes a concentration of a current and brings an injury. An air gap frequently disrupts a treatment and inhibits an output power of the hyperthermic device. Therefore,an air gap filler material has been developed. In this paper,we calculated some models to investigate relations between properties of air gap filler materials and their heating characteristics. In the process,we created several analytical models,which have different contact situations between the human body and the bolus. In the gap filler material insertion models,we developed various types of models,which have different electrical constants and sizes. We calculated current distributions and the SAR distributions of these analytical models. From the results of calculations,we found that an air gap affects the heating characteristics and an air gap filler material can improve heating patterns. Moreover,we confirmed that an air gap filler material,which has low conductivity and larger diameter than bolus,is the most effective in this scenario.
{"title":"Air Gap Filler Material for Hot Spot Reduction in the Capacitive Heating Device","authors":"K. Kumagae, K. Saito","doi":"10.3191/THERMALMED.32.5","DOIUrl":"https://doi.org/10.3191/THERMALMED.32.5","url":null,"abstract":"In capacitive heating, an air gap between a human body and a bolus often causes a concentration of a current and brings an injury. An air gap frequently disrupts a treatment and inhibits an output power of the hyperthermic device. Therefore,an air gap filler material has been developed. In this paper,we calculated some models to investigate relations between properties of air gap filler materials and their heating characteristics. In the process,we created several analytical models,which have different contact situations between the human body and the bolus. In the gap filler material insertion models,we developed various types of models,which have different electrical constants and sizes. We calculated current distributions and the SAR distributions of these analytical models. From the results of calculations,we found that an air gap affects the heating characteristics and an air gap filler material can improve heating patterns. Moreover,we confirmed that an air gap filler material,which has low conductivity and larger diameter than bolus,is the most effective in this scenario.","PeriodicalId":23299,"journal":{"name":"Thermal Medicine","volume":"2 1","pages":"5-11"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90601055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shin Ohta, Yuko Higuchi, Akiko Kitamura, Ryo Kawasaki, Hikaru Kakishita, T. Morioka, Y. Tomoda, H. Narisada, H. Imada, K. Yahara, T. Ohguri
In hyperthermia, it is necessary to heat the tumor over 42.5°C to get anti-tumor effects. However,it is very difficult to heat the target to an ideal temperature,because subcutaneous fat might also be heated simultaneously. Various activities for the improvement of heating more efficiently,such as applying medical jelly, pasting of the tape, the gripping method and reposition of a patient were performed in many therapeutic facilities. In this research,we focused on the other properties to improve the heating efficiency, such as utilization of overlay bolus and the difference of the electrode pad thickness. We tried experimental approach about the difference in heating efficiency according to the two factors.
{"title":"Introduction for Various Activities for Improvement of Heating Efficiency and Dealing of Adverse Events in Hyperthermia","authors":"Shin Ohta, Yuko Higuchi, Akiko Kitamura, Ryo Kawasaki, Hikaru Kakishita, T. Morioka, Y. Tomoda, H. Narisada, H. Imada, K. Yahara, T. Ohguri","doi":"10.3191/THERMALMED.32.1","DOIUrl":"https://doi.org/10.3191/THERMALMED.32.1","url":null,"abstract":"In hyperthermia, it is necessary to heat the tumor over 42.5°C to get anti-tumor effects. However,it is very difficult to heat the target to an ideal temperature,because subcutaneous fat might also be heated simultaneously. Various activities for the improvement of heating more efficiently,such as applying medical jelly, pasting of the tape, the gripping method and reposition of a patient were performed in many therapeutic facilities. In this research,we focused on the other properties to improve the heating efficiency, such as utilization of overlay bolus and the difference of the electrode pad thickness. We tried experimental approach about the difference in heating efficiency according to the two factors.","PeriodicalId":23299,"journal":{"name":"Thermal Medicine","volume":"21 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73820460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-01DOI: 10.3191/THERMALMED.32.17
Y. Iseki, Daisuke Anan, Takahiro Saito, Y. Shindo, F. Ikuta, Kenji Takahashi, Kazuo Kato
:This paper describes a new method of non-invasive temperature measurement using ultrasound B-mode images. In the clinic, a real-time monitoring system to acquire the temperature distributions around the targeted area is necessary for effective hyperthermia treatments. We proposed the temperature measurement method by image processing techniques. The method of measuring temperature distributions was based on the thermal dependence of local change in speed of sound and thermal expansion. In this paper,we that the proposed method is useful for effective hyperthermia treatments.
{"title":"Non-Invasive Measurement of Temperature Distributions During Hyperthermia Treatments using Ultrasound B-mode Images","authors":"Y. Iseki, Daisuke Anan, Takahiro Saito, Y. Shindo, F. Ikuta, Kenji Takahashi, Kazuo Kato","doi":"10.3191/THERMALMED.32.17","DOIUrl":"https://doi.org/10.3191/THERMALMED.32.17","url":null,"abstract":":This paper describes a new method of non-invasive temperature measurement using ultrasound B-mode images. In the clinic, a real-time monitoring system to acquire the temperature distributions around the targeted area is necessary for effective hyperthermia treatments. We proposed the temperature measurement method by image processing techniques. The method of measuring temperature distributions was based on the thermal dependence of local change in speed of sound and thermal expansion. In this paper,we that the proposed method is useful for effective hyperthermia treatments.","PeriodicalId":23299,"journal":{"name":"Thermal Medicine","volume":"110 1","pages":"17-30"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86234479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Japanese Government approved the use of health insurance to cover the costs of electromagnetic hyperthermia in combination with radiotherapy in April 1990. In April 1996, electromagnetic hyperthermia was approved for clinical uses other than combination with radiotherapy. However,the established medical remuneration points of hyperthermia in health insurance were scarce, and tend to prohibit widespread use of electromagnetic hyperthermia due to the decreased profitability. Level I evidence based on meta-analysis and phase III study for electromagnetic hyperthermia in combination with radiotherapy was recognized in following various disease;head and neck cancer, breast cancer,malignant melanoma,non-small cell lung cancer,cervical cancer,rectal cancer and bladder cancer for local control rate and/or tumor response rate. Level I evidence for electromagnetic hyperthermia in combination with chemotherapy was also seen in patients with high-grade sarcoma and liver cancer. Improvements of the overall survival rate base on the level I evidence were confirmed in patients with cervical cancer, rectal cancer and high-grade sarcoma. In recent years, promising results for hyperthermia in combination with chemotherapy or chemoradiotherapy based on phase II study were reported. A brief overview of the clinical evidence and future perspective to revise the medical remuneration points for electromagnetic hyperthermia based on prospective trials including ongoing trials is provided in this article.
{"title":"Current Status of Clinical Evidence for Electromagnetic Hyperthermia on Prospective Trials","authors":"T. Ohguri","doi":"10.3191/THERMALMED.31.5","DOIUrl":"https://doi.org/10.3191/THERMALMED.31.5","url":null,"abstract":"Japanese Government approved the use of health insurance to cover the costs of electromagnetic hyperthermia in combination with radiotherapy in April 1990. In April 1996, electromagnetic hyperthermia was approved for clinical uses other than combination with radiotherapy. However,the established medical remuneration points of hyperthermia in health insurance were scarce, and tend to prohibit widespread use of electromagnetic hyperthermia due to the decreased profitability. Level I evidence based on meta-analysis and phase III study for electromagnetic hyperthermia in combination with radiotherapy was recognized in following various disease;head and neck cancer, breast cancer,malignant melanoma,non-small cell lung cancer,cervical cancer,rectal cancer and bladder cancer for local control rate and/or tumor response rate. Level I evidence for electromagnetic hyperthermia in combination with chemotherapy was also seen in patients with high-grade sarcoma and liver cancer. Improvements of the overall survival rate base on the level I evidence were confirmed in patients with cervical cancer, rectal cancer and high-grade sarcoma. In recent years, promising results for hyperthermia in combination with chemotherapy or chemoradiotherapy based on phase II study were reported. A brief overview of the clinical evidence and future perspective to revise the medical remuneration points for electromagnetic hyperthermia based on prospective trials including ongoing trials is provided in this article.","PeriodicalId":23299,"journal":{"name":"Thermal Medicine","volume":"31 1","pages":"5-12"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90108539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It has been a while since the concern for the decline of the presence of hyperthermia treatment in clinical settings is expressed. We examined the Survey of Medical Care Activities in Public Health Insurance to grasp the circumstance. Based on the result released in June 2013,total cases and medical remuneration point for each hyperthermia treatments were as follows:Deep:589 cases & 5,301,000 points,Superficial:31 cases&186,000 points,the total of 620 cases&5,487,000 points respectively. The percentage of hyperthermia treatments in total healthcare expenses was 0.0025%. On annual basis,there are 7,440 presentations of cases and 6.6 billion yen would be spent on treatment. When examined over a period of time,the number of cases seemed to have been increasing since before 2011 or later. Thus, while taking into account error factors in the Survey of Medical Activities in Public Health Insurance, it is considered that hyperthermia treatment is gradually popular.
{"title":"Hyperthermia Treatment in Japan in View of a Review of Survey of Medical Care","authors":"Hiroya Ito, H. Kurosaki","doi":"10.3191/THERMALMED.31.1","DOIUrl":"https://doi.org/10.3191/THERMALMED.31.1","url":null,"abstract":"It has been a while since the concern for the decline of the presence of hyperthermia treatment in clinical settings is expressed. We examined the Survey of Medical Care Activities in Public Health Insurance to grasp the circumstance. Based on the result released in June 2013,total cases and medical remuneration point for each hyperthermia treatments were as follows:Deep:589 cases & 5,301,000 points,Superficial:31 cases&186,000 points,the total of 620 cases&5,487,000 points respectively. The percentage of hyperthermia treatments in total healthcare expenses was 0.0025%. On annual basis,there are 7,440 presentations of cases and 6.6 billion yen would be spent on treatment. When examined over a period of time,the number of cases seemed to have been increasing since before 2011 or later. Thus, while taking into account error factors in the Survey of Medical Activities in Public Health Insurance, it is considered that hyperthermia treatment is gradually popular.","PeriodicalId":23299,"journal":{"name":"Thermal Medicine","volume":"96 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86488862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.3191/THERMALMED.31.13
Y. Iseki, Keito Nakamura, Daisuke Anan, Kazuo Kato
:This paper describes the ultrasound-guided resonant cavity applicator system which has a function for measuring temperature distributions non-invasively. We had already proposed the resonant cavity applicator for non-invasive hyperthermia treatments. In this heating system,it was shown that the applicator could heat deep seated tumor without undesirable hotspots. In addition,the resonant cavity applicator could control the heated area inside tumors corresponding to the symptom of the patients. In the clinic,a real time monitoring system to acquire the targeted area and temperature distributions inside human body is necessary for effective hyperthermia treatments. In this paper, we proposed the ultrasound-guided resonant cavity applicator system which has a possibility of measuring temperature distributions inside human body. The method of measuring temperature distributions was based on the thermal dependence of local change in speed of sound and thermal expansion. Here,we described the method to estimate temperature distributions inside the agar phantom heated by the developed ultrasound-guided resonant cavity applicator. First, we tried to heat the agar phantom inside a hot water bath to discuss the relationship between temperature rises and changes of the ultrasound images. Next, we measured temperature distributions inside the agar phantom heated by the resonant cavity applicator using a diagnostic ultrasound imaging system. Also,we discussed the results of the measured temperature distributions inside the agar phantom for controlling the heated area. From our heating experiments,it was confirmed that the proposed method was useful to measure temperature distributions and hotspot locations inside the heated object non-invasively.
{"title":"Development of Ultrasound-Guided Resonant Cavity Applicator System: - Non-invasive Measurement of Temperature Distributions -@@@- 超音波画像診断装置を用いた非侵襲温度計測 -","authors":"Y. Iseki, Keito Nakamura, Daisuke Anan, Kazuo Kato","doi":"10.3191/THERMALMED.31.13","DOIUrl":"https://doi.org/10.3191/THERMALMED.31.13","url":null,"abstract":":This paper describes the ultrasound-guided resonant cavity applicator system which has a function for measuring temperature distributions non-invasively. We had already proposed the resonant cavity applicator for non-invasive hyperthermia treatments. In this heating system,it was shown that the applicator could heat deep seated tumor without undesirable hotspots. In addition,the resonant cavity applicator could control the heated area inside tumors corresponding to the symptom of the patients. In the clinic,a real time monitoring system to acquire the targeted area and temperature distributions inside human body is necessary for effective hyperthermia treatments. In this paper, we proposed the ultrasound-guided resonant cavity applicator system which has a possibility of measuring temperature distributions inside human body. The method of measuring temperature distributions was based on the thermal dependence of local change in speed of sound and thermal expansion. Here,we described the method to estimate temperature distributions inside the agar phantom heated by the developed ultrasound-guided resonant cavity applicator. First, we tried to heat the agar phantom inside a hot water bath to discuss the relationship between temperature rises and changes of the ultrasound images. Next, we measured temperature distributions inside the agar phantom heated by the resonant cavity applicator using a diagnostic ultrasound imaging system. Also,we discussed the results of the measured temperature distributions inside the agar phantom for controlling the heated area. From our heating experiments,it was confirmed that the proposed method was useful to measure temperature distributions and hotspot locations inside the heated object non-invasively.","PeriodicalId":23299,"journal":{"name":"Thermal Medicine","volume":"9 1","pages":"13-26"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89899878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-01DOI: 10.3191/THERMALMED.30.41
Y. Iseki, Hideaki Takahashi, T. Uzuka, Kazuo Kato
This paper describes a new heating control method of the proposed resonant cavity applicator for non-invasive brain tumor hyperthermia treatments. In the previous study, the resonant cavity applicator for treating brain tumors was proposed. In the present study,a dielectric bolus was used to control the heated location inside brain tumors. The dielectric bolus was divided into four sections filled with dielectric materials,such as water,and was attached to the human head inside the cavity. By changing the dielectric materials inside each section,the heated location could be controlled inside brain tumors. In this paper,first,the method for controlling the heated location with the dielectric bolus was presented. Second,two types of numerical models to calculate temperature distributions were described. First,we used a cylindrical phantom model for the basic study to check the ability of the proposed method. Second,we used a 3-D anatomical human head model which was reconstructed from 2-D medical images by using the 3-D computer aided design (CAD) software. Finally, the temperature profiles calculated by the 3-D finite element method (FEM) and heating experiments heated by the developed heating system were discussed. From the results of computer simulations and heating experiment with the agar phantom,it was confirmed that the results of the computer simulations were in close agreement with the results of the heating experiments with an error of 10% or less. Next,we calculated the temperature distribution of the 3-D anatomical human head model that takes into account the cooling effect of blood flow. The proposed heating method covered approximately 97% of the brain tumor size without an undesirable hotspot. From these results,it was found that the proposed heating control method is useful for effective hyperthermia treatments.
{"title":"A New Heating Control Method for Effective Hyperthermia Treatment of a Brain Tumor Using the Resonant Cavity Applicator with a Segmented Dielectric Bolus","authors":"Y. Iseki, Hideaki Takahashi, T. Uzuka, Kazuo Kato","doi":"10.3191/THERMALMED.30.41","DOIUrl":"https://doi.org/10.3191/THERMALMED.30.41","url":null,"abstract":"This paper describes a new heating control method of the proposed resonant cavity applicator for non-invasive brain tumor hyperthermia treatments. In the previous study, the resonant cavity applicator for treating brain tumors was proposed. In the present study,a dielectric bolus was used to control the heated location inside brain tumors. The dielectric bolus was divided into four sections filled with dielectric materials,such as water,and was attached to the human head inside the cavity. By changing the dielectric materials inside each section,the heated location could be controlled inside brain tumors. In this paper,first,the method for controlling the heated location with the dielectric bolus was presented. Second,two types of numerical models to calculate temperature distributions were described. First,we used a cylindrical phantom model for the basic study to check the ability of the proposed method. Second,we used a 3-D anatomical human head model which was reconstructed from 2-D medical images by using the 3-D computer aided design (CAD) software. Finally, the temperature profiles calculated by the 3-D finite element method (FEM) and heating experiments heated by the developed heating system were discussed. From the results of computer simulations and heating experiment with the agar phantom,it was confirmed that the results of the computer simulations were in close agreement with the results of the heating experiments with an error of 10% or less. Next,we calculated the temperature distribution of the 3-D anatomical human head model that takes into account the cooling effect of blood flow. The proposed heating method covered approximately 97% of the brain tumor size without an undesirable hotspot. From these results,it was found that the proposed heating control method is useful for effective hyperthermia treatments.","PeriodicalId":23299,"journal":{"name":"Thermal Medicine","volume":"1 1","pages":"41-53"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89654588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3191/THERMALMED.30.13
Y. Shindo, Kazuki Watanabe, K. Kodera, Kazuo Kato, H. Kurosaki, Kenji Takahashi
:This paper describes experimental results of a new heating method for treating osteoarthritis in the knee using a resonant cavity applicator. In the previous study, we proposed a new heating method using a resonant cavity applicator for thermotherapy of osteoarthritis,and discussed the calculated temperature distributions using 3D FEM. From these estimated results, it was found that the proposed heating method is useful for treating osteoarthritis in the knee. In paper,the thermal properties of the proposed method are discussed with experimental results using the prototype applicator with several types of agar phantoms. And the experimental results of the resonant cavity applicator were compared with that of the microwave diathermy system,which is used in Furthermore, in order to resemble real-life conditions, a cow knee was used in the heating experiment. First, experimental results of a cylindrical agar phantom with the proposed method and the microwave diathermy system are discussed. Second, temperature distributions of an agar phantom shaped like a human leg using both methods are presented. Third,the experimental result using the cow knee is discussed. From the experimental results,it is found that the proposed heating method using the resonant cavity applicator is effective for treating osteoarthritis in the knee.
{"title":"Heating Properties of Resonant Cavity Applicator for Treatment of Osteoarthritis","authors":"Y. Shindo, Kazuki Watanabe, K. Kodera, Kazuo Kato, H. Kurosaki, Kenji Takahashi","doi":"10.3191/THERMALMED.30.13","DOIUrl":"https://doi.org/10.3191/THERMALMED.30.13","url":null,"abstract":":This paper describes experimental results of a new heating method for treating osteoarthritis in the knee using a resonant cavity applicator. In the previous study, we proposed a new heating method using a resonant cavity applicator for thermotherapy of osteoarthritis,and discussed the calculated temperature distributions using 3D FEM. From these estimated results, it was found that the proposed heating method is useful for treating osteoarthritis in the knee. In paper,the thermal properties of the proposed method are discussed with experimental results using the prototype applicator with several types of agar phantoms. And the experimental results of the resonant cavity applicator were compared with that of the microwave diathermy system,which is used in Furthermore, in order to resemble real-life conditions, a cow knee was used in the heating experiment. First, experimental results of a cylindrical agar phantom with the proposed method and the microwave diathermy system are discussed. Second, temperature distributions of an agar phantom shaped like a human leg using both methods are presented. Third,the experimental result using the cow knee is discussed. From the experimental results,it is found that the proposed heating method using the resonant cavity applicator is effective for treating osteoarthritis in the knee.","PeriodicalId":23299,"journal":{"name":"Thermal Medicine","volume":"8 1","pages":"13-25"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74215339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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