Optimisation in Radiotherapy

Details

Title

Optimisation in Radiotherapy

Type

Stage Two

Module code

HPE128

Requirement

Compulsory

Module objective

By the end of this module the Clinical Scientist in HSST will be able to analyse, synthesise, evaluate and apply knowledge with respect to optimising treatment plans for external beam radiotherapy and brachytherapy, in a manner consistent with the roles and responsibilities of a Medical Physics Expert, to ensure the safety and efficacy of medical radiation exposures for patients.

Knowledge and understanding

By the end of this module the Clinical Scientist in HSST, in their own area of Medical Physics practice, will be able to analyse, synthesise, critically evaluate and apply knowledge, and will:

• Compare and contrast the use of different imaging modalities in the radiotherapy pathway, including the:
  • use of the various imaging modalities (including positron emission tomography (PET)/CT, PET/MRI, and ultrasound) in the different stages of the radiation oncology process;
  • use of imaging in the simulation process, including conventional simulation, CT/cone beam CT simulators and virtual simulation;
  • functioning and characteristics of the various types of in-room imaging devices;
  • importance of geometrical accuracy (including its repeatability and stability) of imaging devices for radiation oncology;
  • way that acquisition data are processed to facilitate the extraction of information;
  • principles and methods of image post-processing, including knowledge-based image analysis, pattern theory, deterministic image processing and feature enhancement, image segmentation, image registration and co- registration/fusion.
• Describe and evaluate the issues of patient organ motion and methods of immobilisation and management, including the:
  • methods for management of patient organ motion in radiotherapy, including tracking and the use of fiducials;
  • assessment of geometric motion, including:
    • systematic, random, infraction, trends
    • margin calculation
    • quantification of setup errors.
  • Critically evaluate the radiotherapy treatment planning process, including:
    • the use of International Commission on Radiation Units (ICRU) terminology and recommendations regarding target volumes (e.g. Gross Tumour Volume (GTV), Clinical Target Volume (CTV), Planning Target Volume (PTV), Planning organ at Risk Volume (PRV)), organs at risk, and specification of dose and volumes, margin decisions, including international recommendations (including relevant ICRU guidelines and European Guidelines for Quality Assurance in Radiotherapy);
    • how to quantitatively describe the radiation fields produced by external beam devices and their clinical specification;
    • the behaviour of electron beams in non-uniform situations;
    • how to specify beam quality in terms of quality index for photons beams and range/energy parameters for electron beams;
    • the characteristics of clinical beams in air and water/solid phantoms;
    • how to compare national and international treatment protocols for different irradiation techniques with those used at own institution;
    • the effect of various beam arrangements, beam modification devices (hard and virtual wedges, compensators, blocks, Multileaf Collimators (MLCs), bolus) and beam weights on dose distribution
    • the various meanings of the term ‘normalisation’;
    • how intensity-modulated radiotherapy (IMRT) techniques are used for creating optimised dose distributions: fixed-gantry IMRT (static or dynamic MLC), rotating-gantry IMRT (serial and helical tomotherapy, intensity- modulated arc therapy), Cyberknife, stereotactic adaptive radiotherapy (SART);
    • the process of inverse optimisation and the formation of the cost function;
    • approaches to motion management in treatment planning;
    • how to compare different levels of treatment planning complexity in relation to clinical requirements and the uncertainties involved;
    • in mathematical terms, the use of dose calculation algorithms (correction- based, model-based and Monte Carlo) for photon and electron beams;
    • pre-planning models for intracavitary and interstitial brachytherapy (GEC ESTRO, Manchester, Paris, image-guided planning).
• Critically evaluate the risk to patients from ionising radiation, including those from research exposures, including:
  • the magnitude of patient whole body exposure arising from different radiotherapy treatment modalities and concomitant exposures;
  • the principles of patient risk management as applied to ionising radiations;
  • the process and practical implementation of patient risk assessments, using techniques for the qualitative and quantitative assessment of risk;
  • how research exposures are managed, including the processes of ethical review and the use of dose constraints where appropriate.

Technical and clinical skills

By the end of this module the Clinical Scientist in HSST will be able to critically apply their knowledge and understanding to develop and evaluate investigative strategies/procedures/processes that take account of relevant clinical and scientific evidence and other sources of information, and would be expected to critically reflect on their performance and apply in practice a range of clinical skills and will be able to:

• Critically apply their understanding of the imaging and immobilisation in the pre- treatment phase by:
  • analysing acquisition protocols in CT, PET and MRI, and the effect of user set parameters on the appearance of the image and its clinical utility and dosimetric implications for radiotherapy;
  • importing multimodality imaging data and performing image fusion for target volume delineation and planning;
  • advising on the use of immobilisation (including stereotactic) devices.
• Critically apply their understanding of radiotherapy treatment planning by:
  • using images from different modalities in the treatment planning process;
  • creating optimised patient-specific dose distributions using beam combinations, beam shaping, weighting and normalisation, wedges, bolus, compensators, multi-leaf collimators, field matching;
  • analysing dose specifications and volume definitions according to national and international protocols and recommendations;
  • auditing and reviewing setup errors and recommend margins for different sites and techniques;
  • making recommendations regarding target volumes (e.g. GTV, CTV, PTV, PRV), organ at risks and specification of dose and volumes, margin decisions, including international recommendations;
  • providing clinical advice on appropriate treatment selection, including choice of modality, plan complexity and beam parameters;
  • developing optimised treatment plans for external beam radiotherapy treatments of a suitable set of the most representative tumour sites;
  • developing optimised treatment plans for brachytherapy;
  • creating optimised patient-specific dose distributions for IMRT using a range
  • of techniques (forward/inverse planning, fluence map optimisation): fixed- gantry IMRT (static/dynamic MLC), rotating-gantry IMRT (serial/helical tomotherapy, intensity-modulated arc therapy);
  • critically evaluating treatment plans produced by others, checking the plan is optimal, safe and accurate;
  • advising on the management of patients with implanted devices, including pacemakers, artificial hips and tissue expanders.

• Critically apply their knowledge of radiobiology and radiation risk to patient protection by:
  • critically reviewing a detailed dose-response analysis from clinical data and patient series;
  • using radiobiological dose-effect relationships relevant to estimate patient risk (including adverse incidents involving high exposures);
  • applying the concepts of justification, optimisation and reference levels to patient protection, including the radiation dose from concomitant exposures;
  • providing advice on the development of procedures relating to patient safety to demonstrate compliance with relevant ionising radiation legislation;
  • evaluating the use of radiotherapy within clinical trials and setting dose constraints for research exposures;
  • managing gaps in treatment and providing recommendations to clinicians.
• Critically apply their knowledge of adaptive processes in radiotherapy by:
  • advising on imaging protocols during treatment;
  • critically analysing treatment plans in response to changes in patient shape;
  • critically evaluating methods of deformable registration and automatic segmentation as part of adaptive workflow and providing recommendation to meet the individual clinical requirements.

Attitudes and behaviours

By the end of this module the Clinical Scientist in HSST would be expected to demonstrate the attitudes and behaviours necessary for the role of a Medical Physics Expert working within the limits of professional competence and will be able to:

• Apply evidence-based personal and team professional practice placing the patient at the centre of care and:
  • act in accordance with the principles and practice of patient-centred care, regularly reflecting on their practice and revising judgements and changing behaviour in light of new evidence and feedback;
  • critically assess and evaluate personal and team-related performance in the context of evidence-based patient care and the safety of workers and the public, identifying areas of good practice and make improvements where necessary.
• Display a professional commitment to ethical practice, consistently operating within national and local ethical, legal and governance requirements and:
  • accept professional ethical standards and encourage informed debate and critical reflection within healthcare teams;
  • seek advice of peers, legal bodies and regulators in the event of ethical dilemmas, which could include disclosure and confidentiality;
  • respect requests from patients, workers and the public that information should not be shared unless this puts the patient or others at risk of harm;
  • share and discuss information about patient care with the patient unless they have expressed a wish not to receive such information.
• Apply the principles of Good Scientific Practice and the professional standards performing to the highest standards of personal behaviour in all aspects of professional practice and:
  • lead by example, setting high standards of personal behaviour and acting with openness, fairness and integrity listening to the views of others;
  • work and act in accordance with the requirements for professional regulation;
  • promote professional attitudes, values and behaviours at all times;
  • be truthful and admit to and learn from errors;
  • inform the statutory regulator if they are cautioned, charged with a criminal offence, suspended or have restrictions placed on their own scientific, clinical, or professional practice.
• Consistently operate in accordance with relevant current national legislation, policy and practice and:
  • identify and assess the implications of national legislation, policy and advice for service organisation and delivery of high-quality services;
  • consult with peers and service users as part of obtaining agreement to align services with national legislation, policy and advice.