On-line cone beam CT image guidance for vocal cord tumor targeting

Background and purpose: We are developing a technique for highly focused vocal cord irradiation in early glottic carcinoma to optimally treat a target volume confined to a single cord. This technique, in contrast with the conventional methods, aims at sparing the healthy vocal cord. As such a technique requires sub-mm daily targeting accuracy to be effective, we investigate the accuracy achievable with on-line kV-cone beam CT (CBCT) corrections. Materials and methods: CBCT scans were obtained in 10 early glottic cancer patients in each treatment fraction. The grey value registration available in X-ray volume imaging (XVI) software (Elekta, Synergy) was applied to a volume of interest encompassing the thyroid cartilage. After application of the thus derived corrections, residue displacements with respect to the planning CT scan were measured at clearly identifiable relevant landmarks. The intra- and inter-observer variations were also measured. Results: While before correction the systematic displacements of the vocal cords were as large as 2.4 ± 3.3 mm (cranial-caudal population mean ± SD Σ), daily CBCT registration and correction reduced these values to less than 0.2 ± 0.5 mm in all directions. Random positioning errors (SD σ) were reduced to less than 1 mm. Correcting only for translations and not for rotations did not appreciably affect this accuracy. The residue random displacements partly stem from intra-observer variations (SD = 0.2-0.6 mm). Conclusion: The use of CBCT for daily image guidance in combination with standard mask fixation reduced systematic and random set-up errors of the vocal cords to <1 mm prior to the delivery of each fraction dose. Thus, this facilitates the high targeting precision required for a single vocal cord irradiation. © 2009 Elsevier Ireland Ltd. All rights reserved.

Four-dimensional CT analysis of vocal cords mobility for highly focused single vocal cord irradiation

Background and Purpose: To quantify respiratory motion of the vocal cords during normal respiration using 4D-CT. The final goal is to develop a technique for single vocal cord irradiation (SVCI) in early glottic carcinoma. Sparing the non-involved cord and surrounding structures has the potential to preserve voice quality and allow re-irradiation of recurrent and second primary tumors. Material and methods: Four-dimensional CTs of 1 mm slice thickness from 10 early glottic carcinoma patients were acquired. The lateral dimensions of the air gap separating the vocal cords were measured anteriorly, at mid-level and posteriorly at each phase of the 4D-CTs. The corresponding anterior-posterior gaps were similarly measured. Cranio-caudal vocal cords movements during breathing were derived from the shifts of the arythenoids. Results: The population-averaged mean gap size ± the corresponding standard deviation due to breathing (SD_B) for the lateral gaps was 5.8 ± 0.7 mm anteriorly, 8.7 ± 0.9 mm at mid-level, and 11.0 ± 1.3 mm posteriorly. Anterior-posterior gap values were 21.7 ± 0.7 mm, while cranio-caudal shift SD_B was 0.8 mm. Conclusion: Vocal cords breathing motions were found to be small relative to their separation. Hence, breathing motion does not seem to be a limiting factor for SVCI. © 2008 Elsevier Ireland Ltd. All rights reserved.

Belfast's Traditional Music Scene: A Narrative of Change and Development

Today Belfast is home to a vibrant traditional music scene. There have never been more sessions, concerts, classes or lectures devoted to traditional music in the north's biggest city. A complex system of promoters, performers and listeners has emerged in a city that is growing in confidence as it moves away from the dark days of the Troubles. But how does this system function? While Dowling (2014) has examined the development of traditional music-making in Belfast as it shifted from a pre-conflict to conflict ridden environment, little research has been carried out into the reasons behind the boom in traditional music-making in a post-conflict setting.

This paper examines the impact upon the traditional music scene of the first wave of students to arrive in Belfast after the signing of the Good Friday Agreement in 1998. These musicians, such as Donal O'Connor, Ruadhrai O'Kane and Aidan Walsh have had a lasting impact upon the lives of musicians native to Belfast, helping to bring traditional music to new venues and audiences.

The work of Belfast-based music schools with varying remits, such as Belfast Trad., and the Andersonstown School of Traditional and Contemporary Music, is also examined for the purpose of illustrating how both adults and young people are being educated about their musical heritage.

To be inside someone else's dream: On Music for Sleeping & Waking Minds

Music for Sleeping & Waking Minds (2011-2012) is a new,overnight work in which four performers fall asleep while wearing custom designed EEG sensors which monitor their brainwave activity. The data gathered from the EEG sensors is applied in real time to different audio and image signal processing functions, resulting in continuously evolving multichannel sound environment and visual projection. This material serves as an audiovisual description of the individual and collective neuro physiological state of the ensemble. Audiences are invited to experience the work in different states of attention: while alert and asleep, resting and awakening.

Compositional and Performance Mapping in Computer Chamber Music: A Case Study

The mapping problem is inherent to digital musical instruments (DMIs), which require, at the very least, an association between physical gestures and digital synthesis algorithms to transform human bodily performance into sound. This article considers the DMI mapping problem in the context of the creation and performance of a heterogeneous computer chamber music piece, a trio for violin, biosensors, and computer. Our discussion situates the DMI mapping problem within the broader set of interdependent musical interaction issues that surfaced during the composition and rehearsal of the trio. Through descriptions of the development of the piece, development of the hardware and software interfaces, lessons learned through rehearsal, and self-reporting by the participants, the rich musical possibilities and technical challenges of the integration of digital musical instruments into computer chamber music are demonstrated.