|TITLE||Medical Physics and Radiation Protection in Radiation Oncology (Minor)|
|LEVEL||03 - Years 2, 3, 4 in Modular Undergraduate Course|
|DESCRIPTION||This study-unit applies what was learned in the previous core units to the specialty of Radiation Oncology at a MINOR level. It will lay the groundwork for students to be able to specialise in this specialty at Masters level. The unit includes both external beam photon/electron therapies and brachytherapy. Owing to the increasing importance of proton therapy an introduction to this latest therapeutic modality is also included. The unit follows the recommendations regarding core and specialist Radiation Oncology expertise to be found in the EC documents 'European Guidelines on the Medical Physics Expert' and 'Requirements and methodology for recognition of Radiation Protection Experts'.
The aims of this study-unit are:
- Survey common Radiation Oncology devices and their variants and their use in medical Radiation Oncology procedures;
- Review the functioning, characteristics, strengths and limitations of the various types of available treatment devices;
- Discuss with students clinical treatment planning procedures and techniques in external photon/electron beam radiotherapy and brachytherapy;
- Explain the radiobiological rationale underpinning the various treatment strategies;
- Familiarise students with the terminology used in photon and electron dosimetry and ICRU terminology regarding target volumes, organ at risks and specification of dose and volumes;
- Review the advantages and disadvantages of different dose calculation algorithms used in Treatment Planning Systems;
- Illustrate the various approaches to in-vivo dosimetry and choice of appropriate sensors;
- Discuss the roles of MPE, RPE and RPO in radiation safety in Radiation Oncology;
- Introduce the fundamentals of proton therapy.
1. Knowledge & Understanding
By the end of the study-unit the student will be able to:
- Describe common RO devices and their variants and their use in medical RO procedures;
- Discuss the functioning, characteristics, strengths and limitations of the various types of available treatment devices; capabilities and limitations of the different external beam irradiation techniques; various types of in-room imaging devices; TPS for dose optimization; imaging devices and importance of geometrical accuracy of imaging devices for RO;
- Discuss quantitatively the radiation fields produced by external beam devices and their clinical specification and their characteristics in air and water/solid phantoms;
- Discuss the terminology used in photon and electron dosimetry (e.g., PDD, TMR, TPR, OAR);
- Discuss clinical treatment planning procedures and techniques in external photon and electron beam radiotherapy;
- Discuss and use ICRU terminology and recommendations regarding target volumes (e.g., GTV, CTV, PTV, PRV), organ at risks and specification of dose and volumes, margin decisions, including international recommendations (ICRU 50, 62, 83);
- Discuss the advantages and disadvantages of different dose calculation algorithms used in Treatment Planning systems;
- Random and systematic errors evaluation in radiation therapy;
- Discuss the concepts and methods of relative dosimetry: central axis dose distribution in water, output factors (effects of head scatter and phantom scatter, dependence on treatment parameters), 3D dose distribution, beam profiles (e.g., penumbra region, flatness, and symmetry), effects of beam modifiers such as hard and virtual wedges, compensators and bolus;
- Discuss recommended national and international (e.g., IAEA) absorbed dose measurement protocols based on absorbed dose in water/solid phantoms for photon and electron beams;
- Discuss the various approaches to in-vivo dosimetry for RO beams and discuss choice of appropriate sensors;
- Discuss the theoretical and practical aspects of reference dosimetry for high-energy photons and electrons;
- Discuss the functioning, characteristics, strengths and limitations of sensors used for RAK measurement;
- Define reference conditions for fixed-SSD and isocentric approaches;
- Discuss dose-effect relationships relevant to RO with respect to patient safety including discussion of the physical and biological background, response of tissues to radiation on molecular, cellular and macroscopic level, models (including limitations of existing models) of radiation induced cancer and hereditary risks and radiation effects on humans in general, children and the conceptus;
- Discuss the principles and structure of brachytherapy treatment planning systems, dose calculation algorithms (TG 43, model based algorithms) and optimization algorithms for HDR, LDR and PDR; discuss recommended methods for reference air kerma (RAK) determination for LDR/HDR/PDR brachytherapy sources;
- Discuss P+, utility function and other appropriate models used in optimization of treatment outcomes;
- Discuss the roles of designated RPE and RPO in radiation safety in RO, principles of risk management in the case of workers / public with respect to external beam therapy and brachytherapy;
- Discuss the principles of quality control of external beam, brachytherapy, TPS and associated imaging systems; and
- Discuss the radiobiological rationale underpinning the various treatment strategies (fractionation, dose rate, radiosensitization and reoxygenation) in radiation therapy; therapeutic ratio, tumour control probability, normal tissue complication probability, tolerance doses, dose-volume effects and gaps in treatment.
By the end of the study-unit the student will be able to:
- For each RO modality:
- Extract quantitative data from images required for RO purposes
- Select appropriate phantoms/test tools to QC devices used in RO
- Use a TPS for basic patient specific treatment plan generation and optimization
- Perform basic plan optimization and evaluation using uniformity criteria, constraints, DVHs and biological parameters (TCP, NTCP);
- Analyze dose specifications and volume definitions according to national and international protocols and recommendations (including ICRU 38 and 58, GEC ESTRO, ABS);
- Use conventional techniques for creating optimized patient specific dose distributions using beam combinations, beam shaping, weighting and normalization, wedges, bolus, compensators, MLCs, field matching;
- Archive, back-up and restore treatment plans;
- Participate in the verification of the different steps of treatment: patient positioning, target localisation, and dosimetric verification of the irradiation plan;
- Use the national recommended Code of Practice for the determination of absorbed dose to water from external radiotherapy photon beams;
- Perform constancy checks (e.g.,strontium-90 based) on ionization chambers and calibrate diode dosimeters;
- Perform fractionation calculations, response calculations (using NTCP/TCP models), effective dose calculations and volume effect corrections using established models; and
- Perform independent monitor unit calculation for dosimetric verification of treatment plans.
Main Text/s and any supplementary readings:
- IAEA. (2005). Radiation Oncology Physics - A Handbook for Teachers and Students.
- IAEA. (2009). Clinical Training of Medical Physicists Specializing in Radiation Oncology. Training Course Series 37.
- McDermott, P. & Orton, C. (2018). The Physics & Technology of Radiation Therapy. Medical Physics Publishing.
- Khan, F. M., Gibbons, J. P. & Sperduto, P. W. (2016). Treatment Planning in Radiation Oncology. Walters-Kluwer.
- Martin, C. J. & Sutton, DG. (2015). Practical Radiation Protection in Healthcare. OUP.
- Emerald-Emit project: http://emerald2.eu/cd/Emerald2/
- Webb, S. (1993). The physics of 3-dimensional radiation therapy. IoP.
- Baltas, D., Sakelliou, L. & Zamboglou, N. (2007). The Physics of Modern Brachytherapy for Oncology. CRC.
- Hoskin, P. (2012). Radiotherapy in Practice - External Beam Therapy. OUP.
- Hoskin, P. & Coyle, C. (2011). Radiotherapy in Practice - Brachytherapy. OUP.
- Hoskin, P. & Goh, V. (2010). Radiotherapy in Practice - Imaging. OUP.
|STUDY-UNIT TYPE||Lecture, Independent Study & Tutorial|
|METHOD OF ASSESSMENT||
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It should be noted that all the information in the study-unit description above applies to the academic year 2019/0, if study-unit is available during this academic year, and may be subject to change in subsequent years.