Study type: Therapeutical study (experimental study)

A HF EM installation allowing simultaneous whole body and deep local EM hyperthermia tech./dosim.

By: Mazokhin VN, Kolmakov DN, Lucheyov NA, Gelvich EA, Troshin II
Published in: Int J Hyperthermia 1999; 15 (4): 309-329
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Aim of study (acc. to author)

To design and develop an installation which assures tolerant for the patient whole body hyperthermia procedures, being simple enough and convenient for the physician, and allowing additional local heating of the tumour simultaneously with whole body hyperthermia. The aim of the study is to describe and analyse the design, main features, and achieved parameters of the installation developed to achieve the above mentioned goals.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 13.56 MHz
  • power: 1.5 W (upto 10 W)
Exposure 2: 13.56 MHz
  • power: 1.5 W (upto 10 W)
Exposure 3: 40.68 MHz
  • power: 1.5 W (upto 10 W)
Exposure 4: 40.68 MHz
  • power: 1.5 W (upto 10 W)

General information

All the phantoms used in this study were filled with saline solutions of 7 and 5 g of sodium chloride per liter of deionized water and the walls of the phantom plastic tanks were 2.5 mm thick.

Exposure 1

Main characteristics
Frequency 13.56 MHz
Modulation
Modulation type unspecified
Exposure setup
Exposure source
  • whole body applicator
Chamber human body phantom, 25 cm deep, its torso part 80 cm long x 40 cm wide
Additional info Whole body applicator consisting a resonant circuit coupled via an inductance to 2 coplaner copper electrodes covered with 4 cm thick water bolus
Parameters
Measurand Value Type Method Mass Remarks
power 1.5 W - cf. remarks - upto 10 W
Additional parameter details

The relative SAR distributions at a depth of 10 mm were 0.2, 0.5 and 1 in the torso, 0.04 in the head, 0.16 in the leg and 0.14 in the arm, respectively.

Exposure 2

Main characteristics
Frequency 13.56 MHz
Modulation
Modulation type unspecified
Exposure setup
Exposure source
Chamber rectangular torso phantom/ 80 x 32 x 18 cm³
Parameters
Measurand Value Type Method Mass Remarks
power 1.5 W - cf. remarks - upto 10 W
Additional parameter details

Essential relative SAR (40 % of SAR maximum) was achieved at a depth of upto 20 cm. Relative SAR distributions on the depth in the xz (x upto 15 cm, z upto 15 cm) and yz (y upto 20 cm, z upto 15 cm) planes were 0.4 to 0.7 and 0.2 to 0.7, respectively.

Exposure 3

Main characteristics
Frequency 40.68 MHz
Modulation
Modulation type unspecified
Exposure setup
Exposure source
Chamber Oval muscle phantom/ 60 x 40 x 24 cm³
Additional info Relative SAR distridution measured at a depth of 1 cm by RIA-40 C in xz plane (x upto 15 cm, z upto 20 cm) and yz plane (z upto 20 cm, y upto 15 cm) was 0.09 to 0.5 and 0.05 to 0.5, respectively and in the case RIA-40 C was 0.1 to 0.5 in zy plane (z upto 1 cm and y upto 15 cm) and 0 to 0.5 in zx plane ( z upto 10 cm, x upto 20 cm).
Parameters
Measurand Value Type Method Mass Remarks
power 1.5 W - cf. remarks - upto 10 W

Exposure 4

Main characteristics
Frequency 40.68 MHz
Modulation
Modulation type unspecified
Exposure setup
Exposure source
  • contact flexible microstrip applicator CFMA-40 L or CFMA-40 S
Chamber Oval muscle phantom/ 60 x 35 x 22 cm³
Additional info Relative SAR distridution measured at a depth of 1 cm by CFMA-40 L in xz plane (x upto 10 cm, z upto 15 cm) was 0.1 to 1.0 and 0.1 to 1.0 for CFMA-40 S, respectively
Parameters
Measurand Value Type Method Mass Remarks
power 1.5 W - cf. remarks - upto 10 W

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

The high frequency electromagnetic field, at a frequency of 13.56 MHz, is created by a coplanar capacity type applicator positioned under a distilled water filled bolus that the patient is lying on. The electromagnetic energy being released directly in the deep tissues ensures effective whole body heating to required therapeutic temperatures of up to 43.5°C. Skin temperature can be maintained as low as 39-40.5°C. For deep local hyperthermia, the installation is equipped with additional applicators and a generator operating at a frequency of 40.68 MHz. Controllable power output in the range of 100-800 W at a frequency of 13.56 MHz and 50-350 W at a frequency of 40.68 MHz allows accurate temperature control during whole body hyperthermia, deep local hyperthermia and whole body hyperthermia/deep local hyperthermia procedures. The scattered electromagnetic field strength measured in the vicinity of the operating installation does not exceed security standards.

Study character:

Study funded by