Hyperthermia Therapy Physics

Fessenden, Peter; Hand, J. W.

doi:10.1007/978-3-662-03107-0_14

Cited by 14 publications

(3 citation statements)

References 174 publications

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“…Ideally, the therapeutic range of 40-44 • C should be reached everywhere in the tumor, while healthy tissues should not exceed 42 • C. Particular care should be devoted to avoiding MW radiation in the eyes [11]. Unfortunately, radio-frequency (RF) waves in the MW range are known to be easily absorbed by biological tissues [12], resulting in poor penetration depth. This is especially true for the cerebrospinal fluid (CSF), due to its high conductivity at these frequencies [13].…”

Section: Introductionmentioning

confidence: 99%

Antenna Arrangement in UWB Helmet Brain Applicators for Deep Microwave Hyperthermia

Zanoli

Trefná

2023

Cancers

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Deep microwave hyperthermia applicators are typically designed as narrow-band conformal antenna arrays with equally spaced elements, arranged in one or more rings. This solution, while adequate for most body regions, might be sub-optimal for brain treatments. The introduction of ultra-wide-band semi-spherical applicators, with elements arranged around the head and not necessarily aligned, has the potential to enhance the selective thermal dose delivery in this challenging anatomical region. However, the additional degrees of freedom in this design make the problem non-trivial. We address this by treating the antenna arrangement as a global SAR-based optimization process aiming at maximizing target coverage and hot-spot suppression in a given patient. To enable the quick evaluation of a certain arrangement, we propose a novel E-field interpolation technique which calculates the field generated by an antenna at any location around the scalp from a limited number of initial simulations. We evaluate the approximation error against full array simulations. We demonstrate the design technique in the optimization of a helmet applicator for the treatment of a medulloblastoma in a paediatric patient. The optimized applicator achieves 0.3 °C higher T90 than a conventional ring applicator with the same number of elements.

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Section: Introductionmentioning

confidence: 99%

Antenna Arrangement in UWB Helmet Brain Applicators for Deep Microwave Hyperthermia

Zanoli

Trefná

2023

Cancers

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“…The failure to detect these small focal areas of residual and/or recurrent tumor at an early stage may result in peripheral regrowth, often with unfavorable geometry for successful treatment. 14 In the literature, important techniques and areas of research in EM dosimetry, [15][16][17][18] thermal dosimetry, [19][20][21][22][23][24][25][26] treatment planning, 27 and imaging techniques [28][29][30][31][32][33][34][35][36] have been reviewed. Books discussing thermometry and imaging techniques are also available.…”

Section: Introductionmentioning

confidence: 99%

Thermal Therapy, Part IV: Electromagnetic and Thermal Dosimetry

Habash

Bansal

Krewski

et al. 2007

Crit Rev Biomed Eng

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ABSTRACT:In this article some of the important techniques in electromagnetic (EM) and thermal dosimetry are reviewed. Three major areas are discussed: modeling power deposition and estimation of EM energy absorbed by tissues exposed to EM radiation, electrical-thermal modeling for thermal therapy with various models of heat transfer in living tissues, and thermal dosimetry using invasive and noninvasive thermometry. Knowledge about the temperature distributions achieved can only be obtained by treatment planning of patient therapy. This process is called thermal therapy planning system (TTPS), which is a large and complex system for design, control, documentation, and evaluation of the treatment that also provides data for treatment optimization. Various imaging techniques for guidance and monitoring necessary for clinical treatments are also discussed. The review concludes by suggesting future avenues for investigations.

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“…Clinically, HT can be delivered by electromagnetic wavebased techniques or ultrasound. Due to the large wavelengths and/or high energy absorption rate in tissue, electromagnetic heating is hard to be localized when targeting deep sites, hence it is mostly limited to superficial disease or regional heating for deep targets [37]. Ultrasound can provide increased localization to depths ranging from less than 1 cm to 10 cm or deeper by adjusting the frequency and/or utilizing focused beams [38,39].…”

mentioning

confidence: 99%

Targetability of cervical cancer by magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU)-mediated hyperthermia (HT) for patients receiving radiation therapy

Zhu

Huang

Lam

et al. 2021

International Journal of Hyperthermia

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Purpose: To evaluate the targetability of late-stage cervical cancer by magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU)-induced hyperthermia (HT) as an adjuvant to radiation therapy (RT). Methods: Seventy-nine cervical cancer patients (stage IIIB-IVA) who received RT with lesions visible on positron emission tomography-computed tomography (PET-CT) were retrospectively analyzed for targetability using a commercially-available HT-capable MRgHIFU system. Targetability was assessed for both primary targets and/or any metastatic lymph nodes using both posterior (supine) and anterior (prone) patient setups relative to the transducer. Thirty-four different angles of rotation along subjects' longitudinal axis were analyzed. Targetability was categorized as: (1) Targetable with/without minimal intervention; (2) Not targetable. To determine if any factors could be used for prospective screening of patients, potential associations between demographic/anatomical factors and targetability were analyzed. Results: 72.15% primary tumors and 33.96% metastatic lymph nodes were targetable from at least one angle. 49.37% and 39.24% of primary tumors could be targeted with patient laying in supine and prone positions, respectively. 25 -30 rotation and 0 rotation had the highest rate of the posterior and anterior targetability, respectively. The ventral depth of the tumor and its distance to the coccyx were statistically correlated with the anterior and posterior targetability, respectively. Conclusion: Most late-stage cervical cancer primaries were targetable by MRgHIFU HT requiring either no/minimal intervention. A rotation of 0 or 25 -30 relative to the transducer might benefit anterior and posterior targetability, respectively. Certain demographic/anatomic parameters might be useful in screening patients for treatability.

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Hyperthermia Therapy Physics

Cited by 14 publications

References 174 publications

Antenna Arrangement in UWB Helmet Brain Applicators for Deep Microwave Hyperthermia

Antenna Arrangement in UWB Helmet Brain Applicators for Deep Microwave Hyperthermia

Thermal Therapy, Part IV: Electromagnetic and Thermal Dosimetry

Targetability of cervical cancer by magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU)-mediated hyperthermia (HT) for patients receiving radiation therapy

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