Progress on thermobrachytherapy surface applicator for superficial tissue disease

Arunachalam, Kavitha; Craciunescu, Oana; Maccarini, Paolo F.; Schlorff, Jaime L.; Markowitz, Edward; Stauffer, Paul R.

doi:10.1117/12.809493

Cited by 4 publications

(5 citation statements)

References 29 publications

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“…Over the years, we improved the design of the TBSA to combine HDR brachytherapy and heat using 915 MHz conformal microwave array (CMA) applicators. The TBSA is designed for thermoradiotherapy of diffuse chest wall recurrence which typically extends from the skin to a depth of 10-15 mm (Arunachalam et al 2009a, Craciunescu et al 2009. The TBSA reported in this work employs a recently optimized water bolus design with dual-input and dual-output (DIDO) flow channels that produce a more uniform flow distribution across the large target surface (Arunachalam et al 2009b).…”

Section: Introductionmentioning

confidence: 99%

Thermal characteristics of thermobrachytherapy surface applicators for treating chest wall recurrence

et al. 2010

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Purpose To study temperature and thermal dose distributions of ThermoBrachytherapy Surface Applicators (TBSA) developed for concurrent or sequential high dose rate (HDR) brachytherapy and microwave hyperthermia treatment of chest wall recurrence and other superficial disease. Methods A steady state thermodynamics model coupled with the fluid dynamics of water bolus and electromagnetic radiation of hyperthermia applicator is used to characterize the temperature distributions achievable with TBSA applicators in an elliptical phantom model of the human torso. Power deposited by 915 MHz conformal microwave array (CMA) applicators is used to assess the specific absorption rate (SAR) distributions of rectangular (500 cm2) and L-shaped (875 cm2) TBSA. The SAR distribution in tissue and fluid flow distribution inside the Dual-Input Dual-Output (DIDO) water bolus are coupled to solve the steady state temperature and thermal dose distributions of rectangular TBSA (R-TBSA) for superficial tumor targets extending 10–15 mm beneath the skin surface. Thermal simulations are carried out for a range of bolus inlet temperature (Tb=38–43°C), water flow rate (Qb=2–4 L/min) and tumor blood perfusion (ωb=2–5 kg/m3/s) to characterize their influence on thermal dosimetry. Results Steady state SAR patterns of R- and L-TBSA demonstrate the ability to produce conformal and localized power deposition inside tumor target sparing surrounding normal tissues and nearby critical organs. Acceptably low variation in tissue surface cooling and surface temperature homogeneity was observed for the new DIDO bolus at 2 L/min water flow rate. Temperature depth profiles and thermal dose volume histograms indicate bolus inlet temperature (Tb) to be the most influential factor on thermal dosimetry. A 42 °C water bolus was observed to be the optimal choice for superficial tumors extending 10–15 mm from the surface even under significant blood perfusion. Lower bolus temperature may be chosen to reduce thermal enhancement ratio (TER) in the most sensitive skin where maximum radiation dose is delivered and to extend thermal enhancement of radiation dose deeper. Conclusion This computational study indicates that well-localized elevation of tumor target temperature to 40–44 °C can be accomplished by large surface-conforming TBSA applicators using appropriate selection of coupling bolus temperature.

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Section: Introductionmentioning

confidence: 99%

Thermal characteristics of thermobrachytherapy surface applicators for treating chest wall recurrence

et al. 2010

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“…Several multiple element array applicators have been reported in the literature, but have not been characterized for heating properties over contoured anatomy. For this effort, electromagnetic (EM) and thermal simulations were performed using commercial software and 3D simulation approaches that have been described previously for EM (63, 64, 66) and thermal (34, 35, 68, 73) modeling of planar applicators. EM simulations were performed with HFSS (Ansoft Corp, Pittsburg PA) for a 42×27cm L-shape CMA to assess the ability to deliver localized heating to diffuse chestwall disease that extends from the sternum over a mastectomy scar and around the side to the back.…”

Section: Resultsmentioning

confidence: 99%

“…a) Buried coplanar waveguide feedline design to excite a single PCB square slot aperture with matching stubs on the fixed-width coplanar slot feeding each excitation port; b) matched CPW feedline distribution network to 35 element L-shaped CMA array; and c) matching 5–10 mm thick waterbolus coupling layer with optimized circulation for homogeneous temperature across large surface and integral thermal mapping catheters(34, 35). …”

Section: Figures and Tablementioning

confidence: 99%

Conformal microwave array (CMA) applicators for hyperthermia of diffuse chest wall recurrence

Stauffer

Maccarini

Arunachalam

et al. 2010

International Journal of Hyperthermia

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Purpose This article summarizes the evolution of microwave array applicators for heating large area chestwall disease as an adjuvant to external beam radiation, systemic chemotherapy, and potentially simultaneous brachytherapy. Methods Current devices used for thermotherapy of chestwall recurrence are reviewed. The largest conformal array applicator to date is evaluated in four studies: i) ability to conform to the torso is demonstrated with a CT scan of a torso phantom and MR scan of the conformal waterbolus component on a mastectomy patient; ii) Specific Absorption Rate (SAR) and temperature distributions are calculated with electromagnetic and thermal simulation software for a mastectomy patient; iii). SAR patterns are measured with a scanning SAR probe in liquid muscle phantom for a buried coplanar waveguide CMA; and iv) heating patterns and patient tolerance of CMA applicators are characterized in a clinical pilot study with 13 patients. Results CT and MR scans demonstrate excellent conformity of CMA applicators to contoured anatomy. Simulations demonstrate effective control of heating over contoured anatomy. Measurements confirm effective coverage of large treatment areas with no gaps. In 42 hyperthermia treatments, CMA applicators provided well-tolerated effective heating of up to 500cm2 regions, achieving target temperatures of Tmin=41.4±0.7°C, T90=42.1±0.6°C, Tave=42.8±0.6°C, and Tmax=44.3±0.8°C as measured in an average of 90 points per treatment. Summary The CMA applicator is an effective thermal therapy device for heating large-area superficial disease such as diffuse chestwall recurrence. It is able to cover over three times the treatment area of conventional hyperthermia devices while conforming to typical body contours.

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“…But with careful planning and execution, safe administration may be possible. One possible solution is to use a thermobrachytherapy surface applicator to deliver a conformal radiation dose with restricted depth of penetration in combination with superficial heating and LTLD to localise treatment to the chest wall [ 31–34 ].…”

Section: Discussionmentioning

confidence: 99%

Two phase I dose-escalation/pharmacokinetics studies of low temperature liposomal doxorubicin (LTLD) and mild local hyperthermia in heavily pretreated patients with local regionally recurrent breast cancer

Zagar

Vujašković

Formenti

et al. 2014

International Journal of Hyperthermia

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PurposeUnresectable chest wall recurrences of breast cancer (CWR) in heavily pretreated patients are especially difficult to treat. We hypothesised that thermally enhanced drug delivery using low temperature liposomal doxorubicin (LTLD), given with mild local hyperthermia (MLHT), will be safe and effective in this population.Patients and methodsThis paper combines the results of two similarly designed phase I trials. Eligible CWR patients had progressed on the chest wall after prior hormone therapy, chemotherapy, and radiotherapy. Patients were to get six cycles of LTLD every 21–35 days, followed immediately by chest wall MLHT for 1 hour at 40–42 °C. In the first trial 18 subjects received LTLD at 20, 30, or 40 mg/m2; in the second trial, 11 subjects received LTLD at 40 or 50 mg/m2.ResultsThe median age of all 29 patients enrolled was 57 years. Thirteen patients (45%) had distant metastases on enrolment. Patients had received a median dose of 256 mg/m2 of prior anthracyclines and a median dose of 61 Gy of prior radiation. The median number of study treatments that subjects completed was four. The maximum tolerated dose was 50 mg/m2, with seven subjects (24%) developing reversible grade 3–4 neutropenia and four (14%) reversible grade 3–4 leucopenia. The rate of overall local response was 48% (14/29, 95% CI: 30–66%), with. five patients (17%) achieving complete local responses and nine patients (31%) having partial local responses.ConclusionLTLD at 50 mg/m2 and MLHT is safe. This combined therapy produces objective responses in heavily pretreated CWR patients. Future work should test thermally enhanced LTLD delivery in a less advanced patient population.

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Progress on thermobrachytherapy surface applicator for superficial tissue disease

Cited by 4 publications

References 29 publications

Thermal characteristics of thermobrachytherapy surface applicators for treating chest wall recurrence

Thermal characteristics of thermobrachytherapy surface applicators for treating chest wall recurrence

Conformal microwave array (CMA) applicators for hyperthermia of diffuse chest wall recurrence

Two phase I dose-escalation/pharmacokinetics studies of low temperature liposomal doxorubicin (LTLD) and mild local hyperthermia in heavily pretreated patients with local regionally recurrent breast cancer

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