SU-E-J-143: Characteristics of Tumor-Motion Surrogate Signals Analyzed Using Empirical Mode Decomposition and Hilbert-Huang Transformation.

PURPOSE: We introduce a novel technique for analyzing tumor-motion surrogate signals using Empirical Mode Decomposition (EMD) and Hilbert-Huang Transformation (HHT). METHODS: The tumor-motion surrogate signals were acquired (with RPM/Varian), from 20 lung-cancer patients in free-breathing method and its data were decomposed into Intrinsic Mode Functions (IMFs) using EMD. HHT was then applied to each IMF to obtain instantaneous frequency as a function of time. The Result of the frequency information was compared to Fast Fourier Transformation (FFT) and manual calculation of frequency. Correlation of each IMF with the surrogate signal was used to determine the adequate IMF as a faithful tumor-motion surrogate. RESULTS: The surrogate RPM signals were decomposed to 10 ± 1 IMFs on average. The decomposed IMFs showed three categories of frequencies: (1) high frequencies (1 - 10 Hz) such as a noise-like signal, (2) medium frequencies (0.1 - 0.3 Hz), which is potentially a true breathing signal, and (3) low frequencies (0.003 - 0.09 Hz), which behave a baseline drift. The marginal frequency, which is a measure of total amplitude contribution from each frequency, showed an average difference of -0.03 ± 0.07 from the FFT and -0.02 ± 0.05 with the manual calculations. Each surrogate signal showed a high correlation with one IMF (0.747 on average) and, a low correlation with the rest of the IMFs (0.139 on average). The IMF with a high correlation alone represented the surrogate signal well in terms of breathing frequency and amplitude. CONCLUSIONS: The EMD and HHT were used to analyze the cyclic components of nonlinear and non-stationary surrogate signals in the time domain. Since the EMD decomposes the signal into physically-meaningful modes, it was possible to determine IMFs that represent the tumor motion faithfully after removing noise-like signals. Further investigation on physical meanings of the IMFs is the next step of the study.

The accuracy of dose-rate-regulated tracking: a parametric study.

Dose-rate-regulated tracking (DRRT) is a novel tumor-tracking technique based on a preprogrammed multileaf-collimator (MLC) sequence and dose-rate modulation. We have performed a parametric study on how limitations of the DRRT system and breathing irregularities affect the tracking error and the duty cycle of DRRT. The time delay and the allowed dose-rate increment (continuous-, discrete-increment or beam switching) were used as two parameters for the DRRT system limitation. The breathing irregularity was quantified in terms of three variables, namely, breathing period variation, variation of peak-to-peak amplitude and baseline drift. DRRT treatments were simulated using 2126 breathing cycles obtained from 24 lung-cancer patients. Tracking errors and duty cycles from all 24 patients were combined to evaluate their dependence on each parameter or variable. The tracking error and the duty cycle show a modest difference among the three dose-rate-increment cases. Time delay, breathing peak-to-peak variation and baseline drift are the main factors affecting tracking error. The duty cycle is affected mostly by the allowed dose-rate increment, peak-to-peak variation and baseline drift.

Korean translation and validation of the functional assessment of cancer therapy-breast (FACT-B) scale version 4.

We undertook to translate and cross-culturally adapt the Functional Assessment of Cancer Therapy-Breast (FACT-B) scale into Korean and to evaluate its reliability and validity. The translation procedure followed the standard Functional Assessment of Chronic Illness Therapy translation methodology. A total of 201 breast cancer patients (mean age, 43.87 years) were studied for psychometric properties of the FACT-B scale. A pre-test of 20 Korean breast cancer patients indicated that the Korean FACT-B scale provided good content coverage and overall comprehensibility. Our results indicated high internal consistency of the FACT-B scale, with Cronbach's alpha coefficients ranging from 0.79 to 0.90. The only exception was the Breast Cancer Scale (BCS), which had a Cronbach's alpha coefficient of 0.67. We can consider that most of the patients in this study had not resumed sexual activity after surgery and found it difficult to comment on this aspect. We also considered that contents of the BCS may have been somewhat heterogeneous. After performing a factor analysis of the BCS data from this study, we identified three factors, accounting 58.8%: psychological distress (5 items, with explained variances of 27.5%), feminine satisfaction (2 items, with explained variances of 17.1%), and physical complaints (2 items, with explained variances of 14.2%). The FACT-B scale also demonstrated good convergent and divergent validity when correlated with the shortened forms of the Profile of Mood States and the Functional Living Index-Cancer (FLIC). We can now evaluate the Quality of Life (QoL) of Korean breast cancer patients using this reliable and valid instrument. Nevertheless our study has the limitation that it did not evaluate the sensitivity to the changes of the patients' QoL in the long term follow-up, and we will supplement it in our further study.

Efficacy of progressive muscle relaxation training and guided imagery in reducing chemotherapy side effects in patients with breast cancer and in improving their quality of life.

GOALS: This study was designed to assess the effectiveness of progressive muscle relaxation training (PMRT) and guided imagery (GI) in reducing the anticipatory nausea and vomiting (ANV) and postchemotherapy nausea and vomiting (PNV) of patients with breast cancer and to measure their effects on the patients' quality of life (QoL). PATIENTS AND METHODS: Thirty chemotherapy-naive patients with breast cancer were randomized to the PMRT and GI group and 30 to the control group. Before each of six cycles of adjuvant chemotherapy, each patient was administered a self-report Multiple Affect Adjective Checklist (MAACL), and incidents of ANV and PNV for the first three postchemotherapy days were recorded. All patients were administered the Functional Assessment of Cancer Therapy-Breast (FACT-B) at baseline and after 3 and 6 months. RESULTS: We found that the PMRT and GI group was significantly less anxious, depressive, and hostile than the control group. We also found that the PMRT and GI group experienced significantly less ANV and PNV and that 6 months after CT, the QoL of the PMRT and GI group was higher than that of the control group. CONCLUSION: These results indicate that PMRT and GI were associated with both the improvements in ANV and PNV and in the QoL of patients with breast cancer.