|Year : 2022 | Volume
| Issue : 3 | Page : 309-310
Review of the book: The intensity-modulated radiation therapy – A clinical overview
Lalit Mohan Aggarwal
Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
|Date of Web Publication||8-Nov-2022|
Lalit Mohan Aggarwal
Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi - 221 005, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Aggarwal LM. Review of the book: The intensity-modulated radiation therapy – A clinical overview. J Med Phys 2022;47:309-10
Authors: Indra J. Das, Nicholas J. Sanfilippo, Antonella Fogliata and Luca Cozzi
Publisher: Institute of Physics Publishing, Temple Circus
House, Temple Way, Bristol BS1 6HG, United
Kingdom (December 29, 2020)
Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) have revolutionized the management of cancer with radiotherapy. This book systematically compiles the knowledge of IMRT/VMAT from its beginning to the present time covering concepts used in IMRT and VMAT. The definitions, terminology, and equipment used for IMRT and VMAT are extensively compiled in a simplified way. It covers intensity modulation, plan optimization, and clinical applications for various anatomical disease sites. It extensively covers the contouring and imaging aspects required for successful IMRT.
This book was published in December 2020 by the Institute of Physics Publishing. It is written by leading experts who have extensive clinical experience in radiation oncology and medical physics. The authors are globally recognized and they have put their years of experience to simplify the concepts of IMRT/VMAT.
The book covers the advances made in the past 3 decades from compensator-based IMRT to VMAT. It is divided into 20 chapters which extensively cover physics, treatment planning aspects, contouring, optimization, dose calculation, quality assurance (QA), site-specific IMRT/VMAT, and advances in modulated beam technology. The first five chapters are related to the physics and technical details of IMRT. Chapters 6 to 12 deal with contouring, planning, optimization, dose calculation, and QA. Chapters 13 to 19 provide clinical applications of IMRT/VMAT in various major disease sites such as the central nervous system, head-and-neck, lung, breast, prostate, and cervical cancer.
Chapter 1 is an introduction and covers the evolution of traditional two-dimensional radiotherapy to more complex IMRT. It also talks about volume nomenclatures, digitally reconstructed radiographs, and a practical guide to computed tomography simulation.
Chapter 2 gives a glimpse of beam modulation by flattening filters and wedges. It gives a brief introduction to dose normalization, forward planning, and inverse planning. The use of simulated annealing algorithms for planning is introduced in a very simple way.
Chapter 3 deals with the definitions and terminologies used in the IMRT process. IMRT is a digital concept with many terminologies that need to be understood. Therefore, the basic building blocks of the digital world such as a pixel, voxel, bixel-beamlet, intensity, segment, and concept of dose painting are explained in this chapter.
Chapter 4 is devoted to the devices used to modify photon fluence and various treatment innovations in IMRT. The use of filters/compensators, dynamic jaws, and multileaf collimator (MLC) for beam modulation is nicely covered. The concept of fluence modulations through dynamic aperture optimization is explained. The use of binary MLC used for early IMRT implementations with Peacock MIMiC and tomotherapy is extensively covered.
Chapter 5 provides details of static (step and shoot) and dynamic delivery of IMRT. Beam's eye view of structures (planning target volume and organ at risk), segments of MLC for static IMRT, and sequences of sliding windows are explained with the help of figures. Details of intensity-modulated arc therapy and VMAT are provided with figures.
Chapter 6 dwells upon the process of imaging and treatment planning involved in IMRT. Treatment planning of IMRT requires proper defining of target volumes and normal structures. This chapter covers them as per ICRU (International Commission on Radiation Units and Measurements)-50 and 62. Dose Volume Histogram (DVH) constraints, inverse planning, MLC sequencing, and plan approvals are covered along with patient-specific QA and verification of treatment parameters.
Chapter 7 covers in detail the contouring and its requirement for inverse planning and execution of IMRT. This chapter also deals with the use of margins around various delineated volumes, motion management, and auto-segmentation. Contouring and margins are nicely explained with the help of colored pictures.
Chapter 8 is dedicated to treatment planning, although this topic was introduced in earlier chapters. Treatment planning starts with the proper choice of beam geometry, therefore, this topic is extensively covered. The role of collimator rotation, noncoplanarity, flattened/unflattened beams, modulation of degrees, and delivery accuracy in the planning process is well explained. The impact of organ motion, streak artifacts (due to metal in dental or hip prosthesis), and/or neutron contamination are also covered.
Chapter 9 deals with the optimization process involved in treatment planning to get the desired dose distribution. The concepts of inverse planning, cost function, optimization objectives, and various optimization algorithms are elaborated. Biological optimization is the need of the hour; therefore, this topic is also explained along with its benefits and deficiencies.
Chapter 10 is very interesting and explains all the dose calculation methods starting from empirical methods to electron transport explicit algorithms. This chapter gives an in-depth description of empirical models, correction, and kernel-based algorithms (pencil beam, Anisotropic Analytical Algorithm, and collapsed cone). The electron transport explicit algorithms (Monte Carlo, Linear Boltzmann Transport Equation) and types of algorithm classification are also explained. Dose-to-medium or dose-to-water and accuracy of the various TPS implementation are an important section of this chapter.
Chapter 11 is related to variability in the treatment plan which may be due to imaging modality, contouring, planning skills of the planner, algorithms used, etc., The knowledge and protocol-based planning are discussed in detail.
Chapter 12 talks about patient-specific intensity-modulated radiotherapy QA tests and the equipment used for it. Patient-specific QA is very important for the successful implementation of IMRT and delivery of the prescribed dose by checking the accuracy of dose calculation, plan transfer, and treatment delivery. The chapter describes the rationale and process of QA. Information about all the methods and instruments used for patient-specific IMRT QA are extensively covered.
Chapter 13 gives an overview of dose prescription and reporting in IMRT. Dose prescription at the reference point (isocenter) in IMRT is not meaningful as it is in Three Dimensional -Conformal Radiation Therapy (3D-CRT). Therefore, this chapter discusses ICRU 83 guidelines for volume-based dose prescription in IMRT and its evaluation by DVH analysis. It is an important chapter to understand the compliance of IMRT prescriptions with ICRU 83 recommendations.
Chapter 14-19 covers the clinical management of central nervous system tumors, head-and-neck cancer, lung cancer, breast cancer, prostate cancer, and cervical cancer with IMRT. Details of epidemiology, anatomy, indications, and treatment techniques are described with the help of required figures.
The last chapter (Chapter 20) is a summary of IMRT techniques and brief information about decision-making artificial intelligence-guided radiation therapy.
The concepts of IMRT/VMAT are explained with the help of figures, pictures, tables, and practical clinical cases. Every chapter has a list of updated references for further reading. The techniques to achieve a dose-based IMRT plan and biological aspects of treatment planning for IMRT are also covered. The book also deals with advanced imaging aspects of treatment planning and delivery. The contributions of PET, MR, and molecular imaging for planning, image guidance, and adaptive radiotherapy are also discussed.
Final comments: This is a well-organized book that provides up-to-date information on IMRT. The authors of the book have poured their years of experience into this book. The book would be quite useful for the teachers and students of radiation oncology, medical physics, and radiation therapy technology. The students preparing to take the American Board of Radiology or College of Medical Physics of India examinations can refer this book. It will help them in understanding the IMRT physics, planning, optimization, technology, and a wide range of clinical applications of IMRT/VMAT in the management of cancer. I am sure, in the next edition, minor typographical errors (if any) will be edited, the index and readers' feedback will be incorporated.