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Magnetic Resonance Imaging
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
Solenoid-type scanners present another practical problem – the discomfort experienced by many from the tunnel-like environment and noise. As mentioned earlier, MRI scanner manufacturers now market “open MRI” scanners designed with more sensitivity to the user's situation. Modern scanners incorporate a clearer field of view (which can be accomplished with a mirror positioned before the patient's face), relaxing music, and less confining geometries. The open MRI scanners present an alternative for imaging small children, the critically ill, or other persons who cannot tolerate confinement. They also permit interventional procedures to be performed simultaneously with the actual imaging.
Foundation of Electromagnetic Theory
Published in Bahman Zohuri, Patrick J. McDaniel, Electrical Brain Stimulation for the Treatment of Neurological Disorders, 2019
Bahman Zohuri, Patrick J. McDaniel
Another example that we can apply Eq. (1.191) is the Solenoid device. A solenoid may be described as N turns uniformly wound on a cylindrical form of radius a and length L. Such a configuration is shown in Figure 1.21.
Short-Lived Positron Emitting Radionuclides
Published in Frank Helus, Lelio G. Colombetti, Radionuclides Production, 2019
To obtain useful amounts of 13NH3 very often large amounts of radioactivity have to be handled. The only safe way requires remote control or automation. A sophisticated system is described by Ido135 who obtains the 13NH3 by only pushing buttons. All reagents and rinsing solutions are injected through solenoid valves by remotely controlled syringes.
The impact of data selection and fitting on SAR estimation for magnetic nanoparticle heating
Published in International Journal of Hyperthermia, 2020
Hattie L. Ring, Anirudh Sharma, Robert Ivkov, John C. Bischof
A comparison among the temperature-time datasets measured the peak-to-peak noise in Etheridge et al. (0.13 °C) was over twice the peak-to-peak noise in Bordelon et al. (0.06 °C). This comparison of noise is indirect, because Etheridge et al. measured heating during 30 s of negligible temperature change with the coil on in control samples, while Bordelon et al. was measured during 30 s prior to turning on power to the inductor in addition to measuring water blank control samples. However, the anticipated noise within the temperature measurement with the coil on is not anticipated to double the peak-to-peak noise. As an example of minor differences in experimental setup is the handling of inhomogeneous fields from the solenoid coil. Bordelon et al. used a well characterized four-turn coil with a measured homogeneous field region to determine sample placement [19,31]. Etheridge et al. simulated the inhomogeneity of their 2.75-turn coil and adjusted the reported magnetic field amplitude.
The effect of electromagnetic fields on survival and proliferation rate of dental pulp stem cells
Published in Acta Odontologica Scandinavica, 2020
Mohammad Samiei, Zahra Aghazadeh, Elaheh Dalir Abdolahinia, Amin Vahdati, Sabalan Daneshvar, Atefe Noghani
A continuous sinusoidal 50 Hz magnetic field was generated by solenoid coils. The solenoid was wound with 720 turns of 1 mm enamel copper wire on a cylindrical core of acrylic tube (inner diameter: 20 cm, height: 24 cm). The solenoid was serially connected to an autotransformer with a voltage percent scale. The autotransformer was connected to 220 V power. The sinusoidal shape of signals to the solenoid was evaluated by an oscilloscope connected to the solenoid. The favourite flux density of the magnetic field was obtained by setting the voltage percentage scale of the autotransformer. The current and voltage to the solenoid for each flux density were assessed by a digital multi-meter (digital HiTESTER.3256-50, Japan) connected to solenoid. Calibration of the system and uniformity was done by a tesla-meter (LEYBOLD DIDACTIC GMBH 51662, Germany) with a probe AXIALE B-SONDE (model: 516.61). The uniformity of the EMF, at the centre of the solenoid, was ±1% where the cultures were located [26].
Design and construction of a Maxwell-type induction coil for magnetic nanoparticle hyperthermia
Published in International Journal of Hyperthermia, 2020
Anilchandra Attaluri, John Jackowski, Anirudh Sharma, Sri Kamal Kandala, Valentin Nemkov, Chris Yakey, Theodore L. DeWeese, Ananda Kumar, Robert C. Goldstein, Robert Ivkov
Simple solenoids (sometimes called ‘air-core’ coils) have been a preferred choice for MFH because they are simple to produce, and they efficiently generate high peak-amplitude fields with limited stray fields extending outside the coil [12,13,18–20,25,33,34]. Simple solenoid coils, however produce a uniform magnetic field only in a limited volume within the coil, and non-uniform three-dimensional field gradients extending in both axial and transverse directions. Park et al. used a nine-turn solenoid to induce heating by eddy current losses in stainless-steel implants in rabbit livers [53]. Stauffer et al. [25,33] designed and tested solenoids, including a double-layer reverse-wound solenoid to overcome field inhomogeneities in solenoids. This design also aimed to reduce the magnitude of electric fields generated between close windings of the solenoid, which can contribute to superficial heating. This electric field effect is a potential issue only for solenoids, and is not necessarily relevant for other geometries such as single-turn coils or Helmholtz pairs. Surface coils, such as spiral pancake coils [12,19,34] deliver fields having amplitude that rapidly decays with distance normal to the coil plane. Such coils are able to provide sufficient field amplitude to generate effective heating for near-surface tumors (∼2 cm) [12,19,54].