Work Domain Analysis for Designing a Radiotherapy System Control Interface

Abstract

Function Total energy delivered*. Energy delivered to cancerous tissue*. Energy delivered to healthy tissue*. Spatial overlap of radiation beams to tumor*. Spatial overlap of radiation beams to healthy tissue *. Real-time location of patient contour*. Direction of organ movement *. Amount of organ movement*. Clearance of patient from mechanical components of the system*. Patient speech. Patient expressions*. Patient movements*. Generalized Function Radiation beam modality. Radiation beam energy. Penetration depth and profile of radiation beam. Direction and rate of change. Shape of radiation beam. Direction and rate of shape change. Direction of radiation beam. Spatial deposit of radiation energy on tumor. MU per beam. Number of beams. Cumulative geometric and dose combination of beams. Rate of energy absorption in tumor tissue*. Spatial deposit of radiation energy on healthy tissue*. Rate of energy absorption in healthy tissue*. Time of breath hold. Breathing pattern. Breathing rate. Patient chest movement amount during breath-hold (indicative of breathing)*. Eyelid movements*. Positions and speeds* of each system component. Physical Function Beam on or off. Time since beam on. MLC shape. Wedge presence. Gantry rotation. Compensator presence*. Bolus presence*. Tumor at planned position or not*. Surrounding tissue at planned position or not*. Surrounding organs moving or stationary*. Patient moving or stationary. Patient speaking or silent. Signs of instability in patient. Position of patient contour*. Imaging source and panels locations. Couch location. Immobilization accessories presence* Physical Form Radiation beam: modality, energy level, number of fractions, MU per fraction, dose rate, shape, isodose curves. MLC: Shape/position, width, field size, velocity of movements, direction of movements, angle. Wedge: position, size, shape. Gantry: angle, rate of movement, direction of movement, position, distance away from patient. Compensator: position, size, shape. Bolus: position, size, shape, type. Tumor: size, shape, location, type of tissue, movement patterns. Tissue at risk: size, shape, location, type of tissue, movement patterns. Surrounding organs: size, shape, location, movement patterns. Patient movements: position, magnitude, velocity and acceleration of movement. Patient speech: contents of speech. Facial expression signals. Patient’s outer body contour: shape, distance to equipment. Imaging source and panels: position, angle, size, shape, direction of movement, rate of movement, distance from patient. Couch: position, size, shape, angle. Immobilization accessories: position, size, shape, type *Cannot be measured with current technology