Errors in temperature measurement by thermocouple probes during ultrasound induced hyperthermia

Hynynen, Kullervo; Martin, C J; Watmough, D.J.; Mallard, J. R.

doi:10.1259/0007-1285-56-672-969

Cited by 79 publications

(34 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…43 The coupling of the RF excitation fields with the thermocouple wire was not observed. This is likely due to the low flip angle and RF power used by the temperature mapping sequence.…”

Section: Discussionmentioning

confidence: 99%

“…Mild hyperthermia is a therapeutic technique where a tissue is exposed to temperatures above normal body temperature (40)(41)(42)(43)(44)(45) • C) for an extended period of time (up to 1 h). 1 Elevated temperatures may induce several biological effects such as impairment of DNA repair mechanisms, 2,3 increased vascular permeability to nanoparticles, 4 and a change in tumor blood flow and oxygenation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High intensity focused ultrasound induced in vivo large volume hyperthermia under 3D MRI temperature control

et al. 2016

View full text Add to dashboard Cite

Purpose: Mild hyperthermia can be used as an adjuvant therapy to enhance radiation therapy or chemotherapy of cancer. However, administering mild hyperthermia is technically challenging due to the high accuracy required of the temperature control. MR guided high-intensity focused ultrasound (MR-HIFU) is a technology that can address this challenge. In this work, accurate and spatially uniform mild hyperthermia is demonstrated for deep-seated clinically relevant heating volumes using a HIFU system under MR guidance. Methods: Mild hyperthermia heating was evaluated for temperature accuracy and spatial uniformity in 11 in vivo porcine leg experiments. Hyperthermia was induced with a commercial Philips Sonalleve MR-HIFU system embedded in a 1.5T Ingenia MR scanner. The operating software was modified to allow extended duration mild hyperthermia. Heating time varied from 10 min up to 60 min and the assigned target temperature was 42.5• C. Electronic focal point steering, mechanical transducer movement, and dynamic transducer element switch-off were exploited to enlarge the heated volume and obtain uniform heating throughout the acoustic beam path. Multiple temperature mapping images were used to control and monitor the heating. The magnetic field drift and transducer susceptibility artifacts were compensated to enable accurate volumetric MR thermometry. Results: The obtained mean temperature for the target area (the cross sectional area of the heated volume at focal depth primarily used to control the heating) was on average 42.0 ± 0.6• C. Temperature uniformity in the target area was evaluated using T10 and T90, which were 43.1 ± 0.6 and 40.9 ± 0.6• C, respectively. For the near field, the corresponding temperatures were 39.3 ± 0.8• C (average), 40.6 ± 1.0• C (T10), and 38.0 ± 0.9• C (T90). The sonications resulted in a concise heating volume, typically in the shape of a truncated cone. The average depth reached from the skin was 86.9 mm. The results show that the heating algorithm was able to induce deep heating while keeping the near-field temperature uniform and at a safe level. Conclusions: The capability of MR-HIFU to induce accurate, spatially uniform, and robust mild hyperthermia in large deep-seated volumes was successfully demonstrated through a series of in vivo animal experiments. C

show abstract

“…43 The coupling of the RF excitation fields with the thermocouple wire was not observed. This is likely due to the low flip angle and RF power used by the temperature mapping sequence.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High intensity focused ultrasound induced in vivo large volume hyperthermia under 3D MRI temperature control

et al. 2016

View full text Add to dashboard Cite

show abstract

“…A heating tank with temperature control ranging from 20-80 C was used as the uniform heating source for the testing samples. The testing samples included pure degassing water, tissuemimicking graphite phantoms (Hynynen et al 1983), and ex vivo porcine muscles. Thermocouples were both inserted into the samples and placed in water to monitor the temperatures.…”

Section: Measurement Of the Speed Of Sound At Different Temperaturesmentioning

confidence: 99%

Instantaneous Frequency-Based Ultrasonic Temperature Estimation During Focused Ultrasound Thermal Therapy

Liu

Shih

et al. 2009

Ultrasound in Medicine & Biology

View full text Add to dashboard Cite

“…For inhomogeneous, and in particular strongly focused fields, the method is open to a number of complicating influences, including those of heat diffusion, thermal conductivity in the lead wires, and non-linear acoustic behaviour (Hynynen et al 1983;Dickinson 1985). It is worth noting, however that, in a form where the thermocouple or other detector is inserted directly into an 'unknown' medium, the method measures true absorption coefficient and thus provides information complementary to measured data on attenuation coefficient (see Chapter 4 and Drewniak et al 1990).…”

Section: Calorimetrymentioning

confidence: 99%

Detection and Measurement of Acoustic Fields

Hill

2004

Physical Principles of Medical Ultrasonics

View full text Add to dashboard Cite

Errors in temperature measurement by thermocouple probes during ultrasound induced hyperthermia

Cited by 79 publications

References 3 publications

High intensity focused ultrasound induced in vivo large volume hyperthermia under 3D MRI temperature control

High intensity focused ultrasound induced in vivo large volume hyperthermia under 3D MRI temperature control

Instantaneous Frequency-Based Ultrasonic Temperature Estimation During Focused Ultrasound Thermal Therapy

Detection and Measurement of Acoustic Fields

Contact Info

Product

Resources

About