INTENSITY MODULATED RADIOTHERAPY & TOMOTHERAPY

''Comparing ''Step & Shoot'' Intensity Modulated Radiotherapy, with Tomotherapy, In Head And Neck Cancer

Acknowledgements

Writing this thesis has been very demanding, challenging and time-consuming, but also remarkable, informative and above all fun. Nevertheless, it feels great to have finally completed my bachelor's or master's thesis and I am now looking forward to a nice relaxing period for recovering. It has been both advantages and drawbacks with the limited amount of earlier research conducted within this area, even though I faced serious troubles but sometimes the advantages of this research luckily were in my favor and have made this research both challenging and interesting. I would like to thank my supervisor -------, professor at -------University, who has been great in guiding my through this thesis, helping me through the difficulties I faced during the entire process and motivated me to work hard. Furthermore, I would like to thank all my friends, for their contributions by sharing their perceptions and opinions with me. Above all I would like to thank my family and teachers that provided me with valuable and constructive criticism.

Abstract

The study assesses and quantifies the promise dosimetric profits of helical tomotherapy (HT) versus step-and-shoot intensity-modulated radiotherapy (SaS-IMRT) for nasopharyngeal carcinoma (NPC). Twenty successive NPC patients curatively treated by HT were examined. Each case was designed by HT and SaS-IMRT (ADAC Pinnacle3) designing scheme, respectively. Dose designs were in evaluation utilising dose capacity histograms (DVH), conformity catalogue (CI), homogeneity catalogue (HI), and negligible dose to 1 cc (Dmin_1cc) of the designed goal capacity (PTV) and a comprehensive value catalogue (CQI) of 10 body components at risk (OARs). The prescribed dose/fractionation was 72 Gy to the PTV, 64.8 Gy to the discretionary PTV, and 54 Gy to the clinically contradictory neck region. The design of 54 Gy to the PTV (PTV54) was utilised to assess the CI and HI in the target. The cumulative doses of the three PTV designs to the OARs were calculated. We discerned the HT designs considerably advanced the CI (improvement ratio: 11.9 ± 5.5%) and HI (improvement ratio: 8.8 ± 1.5%) of the PTV54 in evaluation with SaS-IMRT plans. In supplement, the mean/maximal dose of most of the OARs except chiasm was considerably decreased in HT designs, with the CQI of 0.92 ± 0.08. A contradictory outcome of HT in chiasm was discerned but only considerably disclosed in situations without skull groundwork infiltration. A dosimetric gain in CI and HI of PTV and freeing of OARs was considerably got in HT versus SaS-IMRT designs in NPC patients. Whether such dosimetric superiority in HT could move into clinical benefits desires farther investigation.

Table of Content

Acknowledgementsii

Abstractiii

CHAPTER 01: INTRODUCTION1

Problem Statement1

Rationale of the Research1

Research Question2

Objectives of the Research2

Search Criteria2

Limitations and Suggestion for Future Research2

Assumptions & Limitation3

Reliability4

Validity4

CHAPTER 02: CRITICAL DISCUSSION OF THE LITERATURE6

Intensity-Modulated Radiation Therapy6

CNS and Head and Neck Tumors10

TomoTherapy Hi ArtTM System13

Tomotherapy Planning15

Linac dIMRT planning16

Concurrent Chemotherapy Into Radiotherapy20

Helical tomotherapy22

Institutional Research Ethics Committee23

CHAPTER 03: METHODOLOGY33

Materials and methods33

Study population33

CHAPTER 04: DATA ANALYSIS36

Treatment plans in HT and SaS-IMRT36

Nomenclature of the dosimetric endpoints38

Statistical analysis39

Results40

Conformity of PTV5440

Homogeneity of PTV5443

Dmin_1cc of PTV5444

Dosimetry of OARs44

Dosimetry of OARs for ...