Impact of Number of Segmented Tissues on SAR Prediction Accuracy in Deep Pelvic Hyperthermia Treatment Planning

VilasBoas‐Ribeiro, Iva; Rhoon, Gerard C. van; Drizdal, Tomas; Franckena, Martine; Paulides, Margarethus M.

doi:10.3390/cancers12092646

Cited by 10 publications

(7 citation statements)

References 54 publications

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“…Recent investigations on hyperthermia treatment planning have aimed to simulate temperature patterns as well as specific absorption rate (SAR) distributions, while helping operators visualize the effects of different steering strategies in modern locoregional radiofrequency hyperthermia treatments [ 37 , 38 , 39 ]. We have previously investigated the use of electromagnetic field numerical simulations for reducing subcutaneous fat overheating, which is a major drawback of deep heating using a capacitively coupled heating system [ 40 ].…”

Section: Discussionmentioning

confidence: 99%

Intensity-Modulated Radiotherapy with Regional Hyperthermia for High-Risk Localized Prostate Carcinoma

Nakahara

Ohguri

Kakinouchi

et al. 2022

Cancers

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Background: The purpose of this study was to evaluate the efficacy and toxicity of adding regional hyperthermia to intensity-modulated radiotherapy (IMRT) plus neoadjuvant androgen deprivation therapy (ADT) for high-risk localized prostate carcinoma. Methods: Data from 121 consecutive patients with high-risk prostate carcinoma who were treated with IMRT were retrospectively analyzed. The total planned dose of IMRT was 76 Gy in 38 fractions for all patients; hyperthermia was used in 70 of 121 patients. Intra-rectal temperatures at the prostate level were measured to evaluate thermal dose. Results: Median number of heating sessions was five and the median total thermal dose of CEM43T90 was 7.5 min. Median follow-up duration was 64 months. Addition of hyperthermia to IMRT predicted better clinical relapse-free survival. Higher thermal dose with CEM43T90 (>7 min) predicted improved biochemical disease-free survival. The occurrence of acute and delayed toxicity ≥Grade 2 was not significantly different between patients with or without hyperthermia. Conclusions: IMRT plus regional hyperthermia represents a promising approach with acceptable toxicity for high-risk localized prostate carcinoma. Further studies are needed to verify the efficacy of this combined treatment.

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Section: Discussionmentioning

confidence: 99%

Intensity-Modulated Radiotherapy with Regional Hyperthermia for High-Risk Localized Prostate Carcinoma

Nakahara

Ohguri

Kakinouchi

et al. 2022

Cancers

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“…The modeling procedure was equal to the phantom study, except that we used the MR images taken at the start of treatment with the patient in treatment position for tissue delineation instead of the CT images. Four tissue types were delineated: fat, muscle, bone, and target volume 43–45 . The latter structure was used for hyperthermia treatment planning optimization and delineated by a radiation oncologist.…”

Section: Methodsmentioning

confidence: 99%

“…Four tissue types were delineated: fat, muscle, bone, and target volume. [43][44][45] The latter structure was used for hyperthermia treatment planning optimization and delineated by a radiation oncologist.The MR thermometry FOV included only 25 cm of the total patient volume inside the hyperthermia applicator (Figure 1). This limited FOV would be inadequate for precise electromagnetic field representation since the water bolus would replace the missing volume of the patient model.…”

Section: Patient and Phantom Modelingmentioning

confidence: 99%

POD–Kalman filtering for improving noninvasive 3D temperature monitoring in MR‐guided hyperthermia

et al. 2022

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Background: During resonance frequency (RF) hyperthermia treatment, the temperature of the tumor tissue is elevated to the range of 39-44 • C. Accurate temperature monitoring is essential to guide treatments and ensure precise heat delivery and treatment quality. Magnetic resonance (MR) thermometry is currently the only clinical method to measure temperature noninvasively in a volume during treatment. However, several studies have shown that this approach is not always sufficiently accurate for thermal dosimetry in areas with motion, such as the pelvic region. Model-based temperature estimation is a promising approach to correct and supplement 3D online temperature estimation in regions where MR thermometry is unreliable or cannot be measured. However, complete 3D temperature modeling of the pelvic region is too complex for online usage.Purpose: This study aimed to evaluate the use of proper orthogonal decomposition (POD) model reduction combined with Kalman filtering to improve temperature estimation using MR thermometry. Furthermore, we assessed the benefit of this method using data from hyperthermia treatment where there were limited and unreliable MR thermometry measurements. Methods: The performance of POD-Kalman filtering was evaluated in several heating experiments and for data from patients treated for locally advanced cervical cancer. For each method, we evaluated the mean absolute error (MAE) concerning the temperature measurements acquired by the thermal probes,and we assessed the reproducibility and consistency using the standard deviation of error (SDE). Furthermore, three patient groups were defined according to susceptibility artifacts caused by the level of intestinal gas motion to assess if the POD-Kalman filtering could compensate for missing and unreliable MR thermometry measurements. Results: First, we showed that this method is beneficial and reproducible in phantom experiments. Second, we demonstrated that the combined method improved the match between temperature prediction and temperature acquired by intraluminal thermometry for patients treated for locally advanced cervical cancer. Considering all patients, the POD-Kalman filter improved MAE by 43% (filtered MR thermometry = 1.29 • C, POD-Kalman filtered temperature = 0.74 • C). Moreover, the SDE was improved by 47% (filtered MRThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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“…Other issues are related to the fulfillment of requirements such as reproducibility and control of temperature distribution in the target region. Several efforts have been made to improve heating uniformity and target specificity while minimizing invasiveness in clinics, also comprising the implementation of treatment planning techniques [ 5 , 6 , 7 ]. Indications on how enhancing therapeutic outcomes have been provided by a large number of preclinical studies, but the weak reproducibility and comparability of results have made standardization actions necessary [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Design and Characterization of an RF Applicator for In Vitro Tests of Electromagnetic Hyperthermia

Ferrero

Androulakis

Martino

et al. 2022

Sensors

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The evaluation of the biological effects of therapeutic hyperthermia in oncology and the precise quantification of thermal dose, when heating is coupled with radiotherapy or chemotherapy, are active fields of research. The reliable measurement of hyperthermia effects on cells and tissues requires a strong control of the delivered power and of the induced temperature rise. To this aim, we have developed a radiofrequency (RF) electromagnetic applicator operating at 434 MHz, specifically engineered for in vitro tests on 3D cell cultures. The applicator has been designed with the aid of an extensive modelling analysis, which combines electromagnetic and thermal simulations. The heating performance of the built prototype has been validated by means of temperature measurements carried out on tissue-mimicking phantoms and aimed at monitoring both spatial and temporal temperature variations. The experimental results demonstrate the capability of the RF applicator to produce a well-focused heating, with the possibility of modulating the duration of the heating transient and controlling the temperature rise in a specific target region, by simply tuning the effectively supplied power.

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Impact of Number of Segmented Tissues on SAR Prediction Accuracy in Deep Pelvic Hyperthermia Treatment Planning

Cited by 10 publications

References 54 publications

Intensity-Modulated Radiotherapy with Regional Hyperthermia for High-Risk Localized Prostate Carcinoma

Intensity-Modulated Radiotherapy with Regional Hyperthermia for High-Risk Localized Prostate Carcinoma

POD–Kalman filtering for improving noninvasive 3D temperature monitoring in MR‐guided hyperthermia

Design and Characterization of an RF Applicator for In Vitro Tests of Electromagnetic Hyperthermia

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