Thermal dose determination in cancer therapy

Sapareto, Stephen A.; Dewey, William C.

doi:10.1016/0360-3016(84)90379-1

Cited by 2,185 publications

(1,463 citation statements)

References 17 publications

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“…According to findings from conventional hyperthermia, the onset of tissue damage occurs at approximately 43°C (19). The TD, which has been related to the equivalent heating time around 43°C, has thus been defined to estimate the effect of heating (18,19,32):…”

Section: Td Calculationmentioning

confidence: 99%

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Simultaneous temperature and magnetization transfer (MT) monitoring during high‐intensity focused ultrasound (HIFU) treatment: Preliminary investigation on ex vivo porcine muscle

Peng

Huang

Tseng

et al. 2009

Magnetic Resonance Imaging

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Purpose:To measure temperature change and magnetization transfer ratio (MTR) simultaneously during high-intensity focused ultrasound (HIFU) treatment. Materials and Methods:This study proposed an interleaved dual gradient-echo technique to monitor the heat and tissue damage brought to the heated tissue. The technique was applied to tissue samples to test its efficacy. Results:Ex vivo experiments on the porcine muscle demonstrated that both temperature changes and MTR exhibited high consistency in localizing the heated regions. As the heat dissipated after the treatment, the temperature of the heated regions decreased rapidly but MTR continued to be elevated. Moreover, thermal dose (TD) maps derived from the temperature curves demonstrated a sharp margin in the heated regions, but MTR maps may show a spatial gradient of tissue damage, suggesting complimentary information provided by these two measures.Conclusion:In a protocol of spot-by-spot heating over a large volume of tissue, MTR provides additional values to mark the locations of previously heated regions. By continuously recording the locations of heated spots, MTR maps could help plan the next target spots appropriately, potentially improving the efficiency of HIFU treatment and reducing undesirable damage to the normal tissue. RECENT DEVELOPMENT OF HIGH-INTENSITY FO-CUSED ULTRASOUND (HIFU) technology has offered a potentially new approach to the local ablation of malignant or benign tumors (1,2). By focusing an ultrasound beam at the target tissue, HIFU maximizes the heating damage to the targeted tissue while preserving the surrounding normal tissue. To improve treatment efficiency and ensure patient safety, it is crucial to perform continuous and real-time monitoring of local heat deposition during HIFU treatment. Owing to satisfactory spatial and temporal resolution, high tissue contrast, and no ionizing radiation, MRI is advantageous over other imaging modalities in guiding, monitoring, and controlling the HIFU treatment, and has therefore been used for preheating localization of the targets or postheating evaluation of the treatment effect (3). Several MR parameters, such as the equilibrium magnetization (M 0 ), T1, T2, and the diffusion coefficient of water molecules, are known to exhibit temperature dependence (4 -10). The temperature sensitivity of these parameters, however, is tissue-dependent, nonlinear, or varies with tissue conditions such as thermal coagulation or denaturation (5,11,12). Currently, the MR parameter that is sensitive to temperature and stable under various tissue conditions is the water proton resonant frequency (PRF) shift (5). The method of PRF shift deter-

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Section: Td Calculationmentioning

confidence: 99%

“…The TD, which has been related to the equivalent heating time around 43°C, has thus been defined to estimate the effect of heating (18,19,32):…”

Section: Td Calculationmentioning

confidence: 99%

Simultaneous temperature and magnetization transfer (MT) monitoring during high‐intensity focused ultrasound (HIFU) treatment: Preliminary investigation on ex vivo porcine muscle

Peng

Huang

Tseng

et al. 2009

Magnetic Resonance Imaging

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“…In 1984, Sapareto and Dewey (8) proposed the thermal dose concept, suggesting important relationship between cell death, temperature rise, and exposition time. Direct monitoring of temperature throughout the targeted zone should improve the effectiveness of ablation.…”

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confidence: 99%

“…Direct monitoring of temperature throughout the targeted zone should improve the effectiveness of ablation. MR thermometry, which provides near-real-time temperature maps (9)(10)(11) and enables thermal dose calculation (8) in a noninvasive manner, is considered a very promising tool for this purpose. Despite the difficulties of temperature mapping in the liver, mostly due to low T 2 * values and motion-related artifacts, PRFS-based fast temperature mapping has been shown feasible and stable in vivo, in a range of 1.6-3 C temperature uncertainty, with a temporal resolution of a few seconds and a spatial resolution of 2-3 mm (12)(13)(14).…”

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confidence: 99%

Automatic temperature control for MR-guided interstitial ultrasound ablation in liver using a percutaneous applicator: Ex vivo and in vivo initial studies

Delabrousse¹,

Salomir²,

Birer³

et al. 2010

Magn. Reson. Med.

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Image-guided thermal ablation offers minimally invasive options for treating hepatocellular carcinoma and colorectal metastases in liver. Here, the feasibility and the potential benefit of active temperature control for MR-guided percutaneous ultrasound ablation was investigated in pig liver. An MR-compatible interstitial ultrasound applicator (flat transducer), a positioning system with rotation-translation guiding frame, and an orbital ring holder were developed.Step-by-step rotated elementary lesions were produced, each being formed by directive heating of a flame-shaped volume of tissue. In vivo feasibility of automatic temperature control was investigated on two pigs. Proton Resonance Frequency Shift (PRFS)-based MR thermometry was performed on a 1.5-T clinical scanner, using SENSE acceleration and respiratory gating. MR follow-up of animals and macroscopic analysis were performed at 3 and, respectively, 4 days postprocedure. No sonication-related radiofrequency artifacts were detected on MR images. The temperature controller converged to the target elevation within 62°C unless the requested power level exceeded the authorized limit. Large variability of the controller's applied powers from one sonication to another was found both ex vivo and in vivo, indicating highly anisotropic acoustic coupling and/or tissue response to identical beam pattern along different radial directions. The automatic control of the temperature enabled reproducible shape of lesions (15 6 2 mm radial depth). Magn Reson Med 63:667-679, 2010.V C 2010 Wiley-Liss, Inc.

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“…With the highly focused transducers and short sonications typically used for FUS ablation the temperature rise is proportional to the acoustic power (ie, the effects of nonlinear ultrasound absorption is small (53)), so that controlling the procedure is relatively straightforward when the temperature distribution is monitored. The mechanism by which heat kills tissue is also well understood to allow for the use of an index by which one can control the procedure, such as the thermal dose (54).…”

Section: Cavitation-enhanced Sonicationmentioning

confidence: 99%

Current status and future potential of MRI‐guided focused ultrasound surgery

Jólesz

McDannold

2008

Magnetic Resonance Imaging

112

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The combination of the imaging abilities of magnetic resonance imaging (MRI) with the ability to delivery energy to targets deep in the body noninvasively with focused ultrasound presents a disruptive technology with the potential to significantly affect healthcare. MRI offers precise targeting, visualization, and quantification of temperature changes and the ability to immediately evaluate the treatment. By exploiting different mechanisms, focused ultrasound offers a range of therapies, ranging from thermal ablation to targeted drug delivery. This article reviews recent preclinical and tests clinical of this technology. WHILE ITS POTENTIAL has been recognized for decades (1-4), focused ultrasound (FUS) therapy has been in the incubation phase for a long time. Although it has been tested in numerous animal experiments, its widespread clinical realization has lagged, primarily due to the lack of intraprocedural accurate temperature monitoring. When the idea of MRI-guidance was introduced in connection with FUS and MRI thermometry during sonication was demonstrated (5,6), it was anticipated that MR-guided FUS surgery (MRgFUS) would be widely accepted clinically within a few years. Despite these early expectations, there has been relatively slow progress in the clinical implementation of MRgFUS.Early development concentrated primarily on breast tumors (benign fibroadenoma (7,8) and malignant breast cancer (9,10)). These early implementations of the MRgFUS technology motivated the improvement of transducer technology from single-element transducers to MRI-compatible multielement phase arrays (11). There was also significant progress in MRI thermometry and its use to monitor and control sonications. Importantly, too, methods were developed to robustly quantify temperature changes (12). At first, only 2D temperature maps were obtained by MRI to allow for accurate targeting of the beam (13). Later these thermal images were used to generate maps of the thermal dose (14) that could then be used to tailor the energy deposition using closed-loop feedback control (15). This preclinical work led to the development of the first commercial system by InSightec (Haifa, Israel), the Exablate 2000, the first implementation of a fully integrated MRgFUS system that combined a phased array transducer, a computer-controlled robotic positioner, and a workstation that integrated control based on MR thermometry.The early limited clinical trials of breast tumor treatment (8 -10,16,17) were followed by the first major clinical application: the noninvasive therapy of benign uterine fibroids (18,19). The successful Phase I trial was followed by a multicenter . These clinical trials led to the approval of this technology for the treatment of uterine fibroids in several countries, including the United States. Examples of MR thermometry and postablation imaging of a uterine fibroid ablation are shown in Figure 1.The success of uterine fibroid ablation has invigorated the entire field. Technology has rapidly improved and clinical applications ke...

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Thermal dose determination in cancer therapy

Cited by 2,185 publications

References 17 publications

Simultaneous temperature and magnetization transfer (MT) monitoring during high‐intensity focused ultrasound (HIFU) treatment: Preliminary investigation on ex vivo porcine muscle

Simultaneous temperature and magnetization transfer (MT) monitoring during high‐intensity focused ultrasound (HIFU) treatment: Preliminary investigation on ex vivo porcine muscle

Automatic temperature control for MR-guided interstitial ultrasound ablation in liver using a percutaneous applicator: Ex vivo and in vivo initial studies

Current status and future potential of MRI‐guided focused ultrasound surgery

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