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Background:Immobilisation for patients undergoing brain or head and neck radiotherapy is achieved using perspex or thermoplastic devices that require direct moulding to patient anatomy. The mould room visit can be distressing for patients and the shells do not always fit perfectly. In addition the mould room process can be time consuming. With recent developments in three-dimensional (3D) printing technologies comes the potential to generate a treatment shell directly from a computer model of a patient. Typically, a patient requiring radiotherapy treatment will have had a computed tomography (CT) scan and if a computer model of a shell could be obtained directly from the CT data it would reduce patient distress, reduce visits, obtain a close fitting shell and possibly enable the patient to start their radiotherapy treatment more quickly.Purpose:This paper focuses on the first stage of generating the front part of the shell and investigates the dosimetric properties of the materials to show the feasibility of 3D printer materials for the production of a radiotherapy treatment shell.Materials and methods:Computer algorithms are used to segment the surface of the patient’s head from CT and MRI datasets. After segmentation approaches are used to construct a 3D model suitable for printing on a 3D printer. To ensure that 3D printing is feasible the properties of a set of 3D printing materials are tested.Conclusions:The majority of the possible candidate 3D printing materials tested result in very similar attenuation of a therapeutic radiotherapy beam as the Orfit soft-drape masks currently in use in many UK radiotherapy centres. The costs involved in 3D printing are reducing and the applications to medicine are becoming more widely adopted. In this paper we show that 3D printing of bespoke radiotherapy masks is feasible and warrants further investigation. [ABSTRACT FROM AUTHOR]

Computer Graphics technologies have developed considerably over the past decades. Realistic virtual environments can be produced incorporating complex geometry for graphical objects and utilising hardware acceleration for per pixel effects. To enhance these environments, in terms of the immersive experience perceived by users, the human's sense of touch, or haptic system, can be exploited. To this end haptic feedback devices capable of exerting forces on the user are incorporated. The process of determining a reaction force for a given position of the haptic device is known as haptic rendering. For over a decade users have been able to interact with a virtual environment with a haptic device. This paper focuses on the haptic rendering algorithms which have been developed to compute forces as users manipulate the haptic device in the virtual environment. [ABSTRACT FROM AUTHOR]

Information on Siggraph's 33rd International Conference on Computer Graphics and Interactive Techniques held through 30th July to 3rd August, 2006 at Boston, Massachusetts is presented. The sessions at the conference highlighted information from tutorials on fluid simulation and computational photography to the latest research developments. Several events including installation competitions, graphic display and others marked the conference.

The article focuses on the 323nd International Conference on Computer Graphics and Interactive techniques from July 31 through August 4, 2005 in Los Angeles, California. The theme of the conference was patterned to the motion picture "Star Wars." The lecture of keynote speaker George Lucas dealt with insights on the digital film.

Reports on the Siggraph convention which was held at the Los Angeles Convention Center in California on August 8-12, 2004. Increase in the number of attendees in 2004 compared to the 2003 convention; Products introduced by chip manufacturers ATI, NVIDIA and 3Dlabs; Information on the 3ds max 7 software from Discreet; Highlights of the computer animation festival.

Haptic assistance is an emerging field of research that is designed to improve human-computer interaction (HCI) by reducing error rates and targeting times through the use of force feedback. Haptic feedback has previously been investigated to assist motion-impaired computer users, however, limitations such as target distracters have hampered its integration with graphical user interfaces (GUIs). In this paper two new haptic assistive techniques are presented that utilise the 3DOF capabilities of the Phantom Omni. These are referred to as deformable haptic cones and deformable virtual switches. The assistance is designed specifically to enable motion-impaired operators to use existing GUIs more effectively. Experiment 1 investigates the performance benefits of the new haptic techniques when used in conjunction with the densely populated Windows on-screen keyboard (OSK). Experiment 2 utilises the ISO 9241-9 point-and-click task to investigate the effects of target size and shape. The results of the study prove that the newly proposed techniques improve interaction rates and can be integrated with existing software without many of the drawbacks of traditional haptic assistance. Deformable haptic cones and deformable virtual switches were shown to reduce the mean number of missed-clicks by at least 75% and reduce targeting times by at least 25%. [ABSTRACT FROM AUTHOR]

Haptic assistance is the process of using force feedback to aid the operator in human-computer interaction (HCI). This may take the form of guiding the operator toward a target or assisting them in its selection. Haptic feedback has previously been investigated to assist motion-impaired computer users; however, limitations of previous 2 DOF haptic target acquisition techniques such as gravity wells and high-friction-targets have hampered progress. In this paper, two new haptic-assistive techniques are presented that utilize the 3 DOF capabilities of the Phantom Omni to produce assistance that is designed specifically for motion-impaired computer users. These include haptic cones and V-shaped funnels. To evaluate the effectiveness of the new haptic techniques, a series of point-and-click experiments were undertaken in parallel with cursor analysis to compare the levels of performance. The task required the operator to produce a predefined sentence on the Windows-On-Screen Keyboard. The results of the study prove that higher performance levels can be achieved using techniques that are less constricting than traditional assistance and without many of the drawbacks. Haptic cones produced the most significant results when compared to an unassisted interface with a mean improvement of 53 percent in the number of missed clicks and 145 percent improvement in throughput.