One of the recent advances in Radiation Oncology and Treatment Planning is Volumetric Modulated Arc Therapy (VMAT). The treatment planning and dosimetry is complex for VMAT. The distinctive feature of this book is in providing a concise discussion of different VMAT concepts in simple language without going into too much detail. Another important feature of this book is that it includes an original Research Paper that compares three different VMAT optimization Algorithms (SmartArc, Ergo++ and Autobeam) with one another and against current gold standard and describes the Dosimetry and Modelling. The first 4 chapters provide the knowledge base required to understand the basic VMAT concepts and the research study discussed in 5th Chapter. Furthermore this book explains the Control Point Modelling process so that readers can learn how to do it on their own. The book is written to appeal a wider population including radiographers, students, physicists, dosimetrists and oncologists. Plenty of references are provided for those who would like to do further research and have deeper understanding of the VMAT.

Abstract: To demonstrate the dosimetric potential of volumetric modulated arc therapy (VMAT) for the treatment of patients with medically inoperable stage I/II non-small cell lung cancer (NSCLC) with stereotactic body radiation therapy (SBRT). Fourteen patients treated with 3D-CRT with varying tumor locations, tumor sizes and dose fractionation schemes were chosen for study. The target prescription doses were 48 Gy in 4 fractions, 52. 5 Gy in 5 fractions, 57. 5 Gy in 5 fractions and 60 Gy in 3 fractions for 2, 5, 1 and 6 patients, respectively. VMAT treatment plans with a mix of 2-3 full and/or partial non-coplanar arcs with 5°-25° separations were retrospectively generated using Eclipse version 10. 0. The 3D-CRT and VMAT plans were then evaluated by comparing their target dose, critical structure dose, high dose spillage, and low dose spillage as defined according to RTOG 0813 and RTOG 0236 protocols. The VMAT treatment plans yielded an average 9. 6-33. 7% reduction in dose to critical structures and an average 12. 0-12. 5% increase in conformity compared with the treated 3D-CRT plans. The D2cm improved with VMAT in 11 of 14 cases. The 3 that worsened were still within the acceptance criteria. Of the 14 3D-CRT plans, 7 had a D2cm minor deviation, while only one of the 14 VMAT plans had a D2cm minor deviation. The R50% improved in 13 of the 14 VMAT cases. The 1 case that worsened was still within the acceptance criteria of the RTOG protocol. Of the 14 3D-CRT plans, 7 had an R50% deviation. Only 1 of the 14 VMAT plans had an R50% deviation, but it was still improved compared to the 3D-CRT plan. In this cohort of patients, no dosimetric compromises resulted from planning SBRT treatments with VMAT relative to the 3D-CRT treatment plans actually used in their treatment.

Intensity Modulated Radiation Therapy (IMRT) is a well-known type of external beam radiation therapy. The advancement in technology has had an inevitable influence in radiation oncology as well that has led to a newer and faster dose delivery technique called Volumetric Modulated Arc Therapy (VMAT). Since the presence of the VMAT modality in clinics in the late 2000, there have been many studies in order to compare the results of the VMAT modality with the current popular modality IMRT for various tumor sites in the body such as brain, prostate, head and neck, cervix and anal carcinoma. This is the first study to compare VMAT with IMRT for breast cancer. The results show that the RapidArc technique in Eclipse version 11 does not improve all aspects of the treatment plans for the breast cases automatically and easily, but it needs to be manipulated by extra techniques to create acceptable plans thus further research is needed.

This book, written by a team of international experts, concisely reviews the rationale and clinical application of image-guided total marrow irradiation, a rapidly emerging area in radiation oncology and hematopoietic cell transplantation. The aim is to provide the practicing radiation oncologist, hematologist, medical physicist, and bone marrow transplant researcher with a fundamental understanding of key aspects and an appreciation of the increasing significance of total marrow irradiation as conditioning for bone marrow transplantation. Detailed attention is paid to the impacts of recent advances in radiation therapy technology, functional PET and MRI, and understanding of the response of bone marrow to radiation. Full consideration is also given to the ways in which technological advances in image-guided radiation therapy have created new opportunities to treat bone marrow transplant patients with limited transplant options due to advanced disease, age, or co-morbidities. Further topics covered include the ways in which cancer stem cells and the marrow microenvironment influence response to radiation therapy and the implementation of new-generation predictive radiobiologic factors in the clinic.

With the advancement of technology there is an increasing ability for lesions to be treated with higher radiation doses each fraction. This also allows for low fractionated treatments. Because the patient is receiving a higher dose of radiation per fraction and because of the fast dose falloff in these targets there must be extreme accuracy in the delivery. The 6 DOF couch allows for extra rotational corrections and for a more accurate set-up. The movement of the couch needs to be verified to be accurate and because of this, end to end quality assurance tests for the couch have been made. After the set-up is known to be accurate then different treatment techniques can be studied. SBRT of the Spine has a very fast dose falloff near the spinal cord and was typically treated with IMRT. Treatment plans generated using this technique tend to have streaks of low dose radiation, so VMAT is being studied to determine if this treatment technique can reduce the low dose radiation volume as well as improve OAR sparing. For the 6 DOF couch QA, graph paper is placed on the anterior and right lateral sides of the VisionRT OSMS Cube Phantom. Each rotational shift is then applied individually, with a 3 degree shift in the positive and negative directions for pitch and roll. A mark is drawn on the paper to record each shift. A CBCT is then taken of the Cube and known shifts are applied and then an additional CBCT is taken to return the Cube to isocenter. The original IMRT plans for SBRT of the Spine are evaluated and then a plan is made utilizing VMAT. These plans are then compared for low dose radiation, OAR sparing, and conformity. If the original IMRT plan is determined to be an inferior treatment to what is acceptable, then this will be re-planned and compared to the VMAT plan. The VMAT plans had similar OAR sparing, target coverage, and conformity. In all cases the 50% isodose volume was lower for the VMAT plans. All of the tests for the 6 DOF couch are accurate and good to use in our monthly tests. VMAT has shown to be better than IMRT for Spine SBRT and should be used in all cases, when treating the Spine.

Non-coplanar VMAT has the potential to treat tumors that are located in close proximity of critical organs or that are partially surrounded by normal tissues. The use of dynamic couch-gantry trajectories offers an opportunity for more precise and accurate delivery of radiation during cancer treatments.Despite the improvements that have been seen in non-coplanar VMAT, challenges still persist.In this thesis, we present a methodology for the determination of collision free couch-gantry orientations. This methodology is proposed to avoid the possibility of a collision during the motion of the couch and gantry during treatment.We propose an algorithm based on simulated annealing for non-coplanar VMAT treatment planning. This algorithm is used to select the best possible beam orientations for the accurate delivery of the prescribed dose.We also propose a RRT inspired algorithm for generating the trajectory for the non-coplanarVMAT plan delivery. The algorithm is proposed to solve the problem of the addition of intermediate beam orientations observed in beam selection methods.From the results of studies on the proposed methods, improvements to collision detection, global optimization and trajectory generation for non-coplanar VMAT treatment planning were observed. These improvements include a better dosimetry with respect to reductions in mean dose to the organs-at-risk and a more efficient delivery trajectory.Our studies indicate that there exists a reasonable trade-off between treatment plan quality and plan deliverability if the dosimetry of the VMAT treatment plan is continuously monitored during trajectory generation.