Microwave thermal ablation is under consideration as a minimally invasive modality to treat 10-20 mm benign adrenal adenomas, while preserving normally functioning adjacent adrenal tissue, and returning the gland to a normally functioning status that is under normal regulation. In contrast to applications for tumor ablation, where devices have been developed with the objective of maximizing the size of the ablation zone for treating large tumors, a challenge for adrenal ablation is to minimize thermal damage to non-targeted adrenal tissue and thereby preserve adrenal function. Here, we investigate methods for creating small spherical ablation zones of volumes in the range 0.5-4 cm 3 for the treatment of benign adrenal adenomas using water-loaded microwave monopole antennas operating at 2.45 GHz and 5.8 GHz. Coupled electromagnetic and bioheat transfer simulations and experiments in ex vivo tissue were employed to investigate the effect of frequency, applied power, ablation duration, and coolant temperature on the length and width of the ablation zone. Experimental results showed that small spherical ablation zones with diameters in the range of 7.4-17.6 mm can be obtained by adjusting the applied power and ablation duration. Multi-way ANOVA analysis of the experimentally-measured ablation zone dimensions demonstrated that frequency of operation and ablation duration are the primary parameters for controlling the ablation zone length and width, respectively. Additionally, it was demonstrated that the coolant temperature provides another effective parameter for controlling the ablation zone length without affecting the ablation zone width. Our study demonstrates the feasibility of creating small spherical microwave ablation zones suitable for targeting benign adrenal adenomas.
Microwave thermal ablation is under consideration for minimally invasive treatment of bilateral adrenal adenomas, symptomatic of Conn's syndrome. Currently available microwave technologies are ill-suited to precise ablation of small adrenal targets. We report on our preliminary computational and experimental efforts towards the design of microwave ablation systems for targeting adrenal masses. Broadband dielectric properties of ex vivo bovine adrenal glands were experimentally measured. Computer simulations demonstrated the feasibility of achieving precise ablation of adrenal lesions with 2.45 GHz systems. Experiments in ex vivo adrenal tissue using a water-cooled 2.45 GHz antenna illustrated the feasibility of heating 10-20 mm adrenal targets with 40 W power applied for 1 min. These preliminary results warrant further investigation and development of microwave technology for precise ablation of adrenal masses.
− Dielectric properties of biological tissue are important in safety assessment and evaluation of novel medical imaging and therapeutic devices. This paper reports frequency dependent dielectric properties of adrenal tissue, which is a potential target for microwave ablative therapy to treat benign and malignant adrenal tumors. Dielectric properties of bovine adrenal glands were measured using open-ended coaxial probe over 0.5 to 20 GHz, and a two pole Cole-Cole model was fitted to the measured data. The parameters of Cole-Cole model are presented in this paper.
12050 Background: Emotional support (ES) is the most frequently reported support need among older adults with cancer. Yet, the association of ES with cancer outcomes is largely unknown. This study examined the association of ES with health-related quality of life (HRQoL), mental health, and survival among older adults with GI malignancies. Methods: We included older adults (≥60y) newly diagnosed with GI cancer and undergoing a self-reported geriatric assessment (GA) at first clinic visit. Self-reported ES, measured by the Medical Outcomes Survey was the primary exposure. Outcomes included physical and mental HRQoL as measured by the Patient-Reported Outcomes Measurement Information System® (PROMIS) 10-item global assessment, anxiety and depression as measured by the PROMIS Anxiety and Depression Short Form 4a, respectively, and one-year, two-year, and overall survival. Linear regression evaluated the association between ES and t-scores of physical/mental HRQoL. Logistic regression evaluated the association of ES with anxiety and depression. Models were adjusted for age, race, sex, and cancer type/stage. Kaplan-Meier curves and log-rank tests evaluated the association between ES and survival outcomes. Results: Overall, 795 participants were included. The median age was 68 (IQR: 64-74) and patients were 58.0% male, and 74.6% White. The most common cancers included colorectal (37.9%) and pancreatic (30.8%), with mostly advanced staged disease (Stage III/IV: 72.1%). A majority (77.6%) had adequate ES. Patients with inadequate ES were more likely to be Black (31.5 vs. 20.8%, p=0.005), disabled (24.1 vs. 10.4%, p<0.001), and widowed/divorced (54.2 vs. 24.8%, p<0.001). After adjustment, patients with inadequate ES had lower physical and mental HRQoL t-scores (Physical β: -3.35, 95% CI: -5.25, -1.46; Mental β: -2.46, 95% CI: -4.11, -0.81) and higher odds of depression (aOR: 2.22, CI: 1.34-3.69). There was no statistically significant association with anxiety (aOR:1.15, CI: 0.73, 1.81). No differences were observed between patients with inadequate versus adequate ES in one-year, two-year, or overall survival (Log-Rank tests: one-year, p=0.952; two-year, p=0.606; overall, p=0.584). Conclusions: Older adults with inadequate ES have higher odds of poor physical and mental HRQoL and depression, but no difference in survival compared to those with adequate ES. Further work is necessary to determine if interventions to improve ES also improve HRQoL and depression.
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