Comparison between audio-only and audiovisual biofeedback for regulating patients' respiration during four-dimensional radiotherapy

PURPOSE: To compare audio-only biofeedback to conventional audiovisual biofeedback for regulating patients' respiration during four-dimensional radiotherapy, limiting damage to healthy surrounding tissues caused by organ movement. MATERIALS AND METHODS: Six healthy volunteers were assisted by audiovisual or audio-only biofeedback systems to regulate their respirations. Volunteers breathed through a mask developed for this study by following computer-generated guiding curves displayed on a screen, combined with instructional sounds. They then performed breathing following instructional sounds only. The guiding signals and the volunteers' respiratory signals were logged at 20 samples per second. RESULTS: The standard deviations between the guiding and respiratory curves for the audiovisual and audio-only biofeedback systems were 21.55% and 23.19%, respectively; the average correlation coefficients were 0.9778 and 0.9756, respectively. The regularities between audiovisual and audio-only biofeedback for six volunteers' respirations were same statistically from the paired t-test. CONCLUSION: The difference between the audiovisual and audio-only biofeedback methods was not significant. Audio-only biofeedback has many advantages, as patients do not require a mask and can quickly adapt to this method in the clinic.

Comparison study on 4D-CT and ABC techniques in respiratory management during lung radiotherapy / 重庆医学

Objective To evaluate the similarities and differences between four-dimensional radiotherapy (4D-CT ) and active breathing control techniques(ABC) in respiratory management in lung radiotherapy ,and investigate the indications and feasibility of different breathing control techniques for different patients .Methods Twenty-one patients treated with lung radiotherapy received respiratory management .4D-CT technology was used in 11 patients ,while ABC technology was adopted in the rest 10 .The ratios of planning target volume(PGTV) to gross tumor volume(GTV)[(PGTV/GTV)] were calculated .The differences between these two respiratory management technologies were compared in terms of the PGTV ,positioning time ,planning time and treatment time to investigate the indications .Results 4D-CT technology had higher PGTV/GTV ratio ,and shorter positioning time and irradiation time than ABC technology(P0 .05) .In patients with ABC and 4D-CT technology ,objective response rates were 50 .0% ,45 .5% ,respectively ,and the radiation pneumonitis rates were 30 .0% ,27 .3% ,respectively .There was no significant difference in both groups (P>0 .05) .Conclusion In lung tumor radiothera-py ,ABC can reduce irradiation volume ,suitable for patients with good performance status .4D-CT is time-saving and well tolerated , suitable for patients with smaller tumors .