A flexible 70 MHz phase-controlled double waveguide system for hyperthermia treatment of superficial tumours with deep infiltration

Stam, Gerard van; Kok, H. Petra; Hulshof, Maarten C.C.M.; Kolff, M.W.; Tienhoven, Geertjan van; Sijbrands, Jan; Bakker, A.; Vörding, Paul J. Zum Vörde Sive; Oldenborg, S.; Greef, Martijn de; Rasch, Coen R. N.; Crezee, J.

doi:10.1080/02656736.2017.1313460

Cited by 10 publications

(11 citation statements)

References 36 publications

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“…However, heating up to a slightly larger depth might be feasible since bending a CFMA increases the penetration depth [21,34]. Simulations might help to determine whether superficial hyperthermia is adequate or whether a system with a lower operating frequency, and thus a larger penetration depth, should be applied, e.g., a 70 MHz CFMA [35] or the 70 MHz AMC-2 system [36]. These systems have been developed for heating superficial tumors with deep infiltration.…”

Section: Discussionmentioning

confidence: 99%

Modelling Curved Contact Flexible Microstrip Applicators for Patient-Specific Superficial Hyperthermia Treatment Planning

Kok

Groen

Bakker

et al. 2020

Cancers

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This paper describes a method to reconstruct bendable superficial hyperthermia applicators for routine clinical patient-specific treatment planning. The reconstruction uses a CT scan with a flexible silicone dummy applicator positioned on the patient. The curvature was approximated by two second-degree polynomial functions. A realistic treatment series was mimicked using a standard Alderson radiation therapy phantom and a treatment planning model was reconstructed from a CT scan. The variation among treatment curvatures was compared to the modelled curvature. The mathematical approximation of the applicator curvature was validated for this phantom experiment, as well as for clinical treatments. The average maximum variation among the successive mimicked sessions was 3.67 ± 0.69 mm (range 2.98–4.60 mm). The maximum deviation between the treatment curvature and the modelled curvature was 4.35 mm. Comparing the treatment and approximated curvature yielded a maximum deviation between 2.98 mm and 4.12 mm. For clinical treatments the maximum deviation of the treatment and approximated curvature varied between 0.48 mm and 1.98 mm. These results allow adequate reconstruction of bendable hyperthermia applicators for treatment planning, which can further improve treatment quality, for example by optimizing the water bolus temperature for patient-specific tumor depths. Predictive parameters for hyperthermia treatment outcome can easily be evaluated and compared for various input parameters.

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Section: Discussionmentioning

confidence: 99%

Modelling Curved Contact Flexible Microstrip Applicators for Patient-Specific Superficial Hyperthermia Treatment Planning

Kok

Groen

Bakker

et al. 2020

Cancers

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“…The water-filled waveguides have a length of 12 cm (¼λ), apertures of 34 × 21 cm, 34 × 15 cm, or 34 × 8.5 cm, and effective penetration depths of 3.5, 3.1, and 2.7 cm, respectively ( Fig. 1(d)) [33]. The effective penetration depth is the depth at which specific absorption rate (SAR) is 50% of the value at 1 cm depth, as defined in the European Society of Hyperthermia (ESHO) Quality Assurance (QA) guidelines [10,34].…”

Section: Methodsmentioning

confidence: 99%

“…This temperature is selected based on the tumor location. More details can be found in [33]. Figure 5 shows patient set-up and temperature results for a patient with multiple large melanoma on his leg.…”

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confidence: 99%

Dedicated 70 MHz RF systems for hyperthermia of challenging tumor locations

Crezee¹,

Zweije

Sijbrands

et al. 2020

Int. J. Microw. Wireless Technol.

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Hyperthermia (i.e. heating of tumor tissue to 40–43°C) is used in clinical oncology to enhance the therapeutic effect of chemotherapy and radiotherapy. Many tumor sites are heated either by a single RF or MW antenna positioned on the tumor location, or by a phased array positioned around the patient. Superficial tumors are generally heated with MW antennas (434–2450 MHz) and deep-seated tumors with RF antennas (70–150 MHz). These devices cover the major, more common tumor sites, but more rare locations require more dedicated applicators. We discuss dedicated RF systems aiming for heating semi-deep-seated tumors in the leg, breast, and upper thorax. Clinical results show that adequate heating is possible with these systems, with achieved temperatures in the therapeutic range.

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“…Hyperthermia treatment of pelvic tumors was simulated for the 70 MHz AMC-4 system, which consists of a ring of four waveguides (fixed aperture size 20x34 cm 2 ) positioned around the patient (28). For the extremities, the 70 MHz AMC-2 system was simulated, consisting of two waveguides positioned at the top and bottom of the target (29). Waveguides with different aperture sizes may be selected for this system, and an aperture size of 20x34 cm 2 was selected.…”

Section: Treatment Simulationsmentioning

confidence: 99%

Re‑irradiation plus hyperthermia for recurrent pediatric sarcoma; a simulation study to investigate feasibility

et al. 2018

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Recurrent pediatric tumors pose a challenge since treatment options may be limited, particularly after previous irradiation. Positive results have been reported for chemotherapy and hyperthermia, but the combination of re-irradiation and hyperthermia has not been investigated thus far, although it is a proven treatment strategy in adults. The theoretical feasibility of re-irradiation plus hyperthermia was investigated for infield recurrent pediatric sarcoma in the pelvic region and the extremities. A total of 46 recurrent pediatric sarcoma cases diagnosed at the Academic Medical Center (Amsterdam, The Netherlands) between 2002 and 2017 were evaluated. Patients not previously irradiated, outfield recurrences and locations other than the pelvis and extremities were excluded, ultimately yielding four eligible patients: Two with sarcomas in the pelvis and two in an extremity. Re-irradiation and hyperthermia treatment plans were simulated for 23x2 Gy treatment schedules and weekly hyperthermia. The radiosensitizing effect of hyperthermia was quantified using biological modelling with a temperature-dependent change in the parameters of the linear-quadratic model. The possible effectiveness of re-irradiation plus hyperthermia was estimated by calculating the equivalent radiotherapy dose distribution. Treatment planning revealed that tumors located in the pelvis and the extremities can be effectively heated in children. Equivalent dose distributions indicated that hyperthermic radiosensitization can be quantified as a target-selective additional D95% of typically 10 Gy, thereby delivering a possibly curative dose of 54 Gy, without substantially increasing the equivalent dose to the organs at risk. Therefore, re-irradiation plus hyperthermia is a theoretically feasible and possibly effective treatment option for recurrent pediatric sarcoma in the pelvic region and the extremities, and its clinical feasibility is worthy of evaluation.

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A flexible 70 MHz phase-controlled double waveguide system for hyperthermia treatment of superficial tumours with deep infiltration

Abstract: This 70 MHz AMC-2 waveguide system is a useful addition to existing loco-regional hyperthermia equipment as it is capable of heating axillary tumours and other tumours deeper than 4 cm.

Cited by 10 publications

References 36 publications

Modelling Curved Contact Flexible Microstrip Applicators for Patient-Specific Superficial Hyperthermia Treatment Planning

Modelling Curved Contact Flexible Microstrip Applicators for Patient-Specific Superficial Hyperthermia Treatment Planning

Dedicated 70 MHz RF systems for hyperthermia of challenging tumor locations

Re‑irradiation plus hyperthermia for recurrent pediatric sarcoma; a simulation study to investigate feasibility

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