Contents Part I Background Principles and Technical Development 1 Introduction and the Nature of Radiosurgery... 3 Definitions of Radiosurgery... 5 Consequences of Changing Definitions of Radiosurgery... 6 Non-neurosurgical Treatments and Fractionation... 6 Microsurgery. Gamma Knife Surgery and Their Relationship to Each Other... 7 Aims of This Book... 8 References... 8 2 Principles of Stereotaxy... 9 Introduction... 9 Principles... 10 The Leksell System... 11 Target Identification... 11 Newer Localization Methods... 13 Modem Indications for Stereotaxy... 15 Conclusion... 15 References... 16 3 Ionising Radiation and Its Effects on Living Tissue... 17 Introduction... 17 Radiophysics... 17 Basic Concepts... 17 Units... 19 Electromagnetic Radiation... 21 Particle Radiation... 22 The Effect of Electromagnetic Radiation on Matter at the Atomic Level... 23 The Effect of Charged Particles on Matter... 25
xiv Contents Consequences of Radiation Induced Damage on Biological Tissue... 28 Early Effects... 28 Radiation Injuries to Nucleic Acid Molecules... 29 Response to Radiation Damage of DNA Molecules... 29 References... 31 4 Biological Effects of Ionising Radiation... 33 Introduction... 33 Cell Survival Studies... 33 The Linear Quadratic Equation... ---... 34 Mechanisms of Cellular Repair... 35 Different Factors Affecting the Effects of Radiation... 38 Biological Factors... 38 Radiation Factors... 40 Clinical Radiobiological Correlates... 43 The Fate of the Normal Tissue... 43 The Fate of Irradiated Tumour Cells... 44... References 46 5 Ionising Radiation and Clinical Practice... 47 Introduction... 47 General Clinicoffathological hnciples... 47 The Therapeutic Index... 47 Time Dose Relationships... 48 Early and Late Reactions... 49 Adverse Radiation Effects in the Brain... 50 Severe Somatic Adverse Radiation Effects in the Brain... 50 Less Severe Somatic Adverse Radiation Effects in the Brain After Gamma Knife Treatment... 51 Genetic Adverse Effects Following Brain Irradiation... 51 References... 52 6 Gamma Knife Development from 1967 to 2010... General Information... Introduction... Preparatory Basic Research... The First Patients... The First Gamma Unit... Early Experience... The Second Gamma Unit... The Third Gamma Unit (Gamma Knives U and B)... Fixation of the Patient to the Gamma Knife... Automatic Positioning...
Contents Gamma Knife Perfexion... 63 Introduction... 63 Design Differences... 64 7 Radiophysics. Radiobiology and the Gamma Knife... 67 Introduction... 67 Radiophysics and the Gamma Knife... 67 Energy... 67 Radiobiology and the Gamma Knife... 68 Factors Affecting Cell Survival... 68 Delayed Radiation Damage of Nervous Tissue and the Gamma Knife... 70 Radiation Tolerance of the CNS... 70 Dose Latency Relationships... 71 Tumour Tissue and the Gamma Knife... 73 Radiobiological Correlates with Single Session Radiosurgery... 74 Relevance of the Linear Quadratic Equation... 74 Relevance of Fractionation... 75 Conclusion... 76 References... 76 8 Preparation for Treatment Planning... 79 Introduction... 79 Frame Application: General Method for Gamma Knife C Models... 79 Frame Placement in the Gamma Knife Helmet for Single Targets... 80 Intracranial Extracerebral Solitary Targets: Frame Displacement... 82 Intracranial Extracerebral Solitary Targets: Frame Rotation... 84 Intracranial Intracerebral Multiple Targets... 86 Intracranial Intracerebral Multiple Targets: Frame Displacement and Rotation... 88 Frame Application: General Method for Gamma Knife Perfexion... 89 Frame Application... 89 The Frame Cap... 89 Imaging: MRI... 90 Sources of Distortion on MR Images... 90 Imaging: Angiogram... 92 DSA Images... 92 References... 94 9 Dose Plan Indices... 99 Dose-Plan Finalisation... 99 Conformity Index: RTOG PITV Index... 99
xvi Contents Target Volume Ratio (TVR)... 99 Paddick Conformity Index (PCI)... 100 Selectivity... 100 Gradient Index... 101 Comment on the Use of Indices... 101... References 102 Part I1 The Patient's Experience... Introduction... 105 The Effect of Computer Networks on the Physician... 105 The Effect of the Computer Networks on the Patient... 107 Computer Networks and Medical Ethics... 107 Conclusion... 108 References... 109 10 Gamma Knife Surgery and Computer Networks 105.................. 11 Aims of Gamma Knife Surgery 111 Introduction 111 What We Want to Do and What We Can Do 111 What Is in the Patient's Best Interest? 112 Conclusion 113 References 113 12 Principles of Information and Follow Up... Introduction: The Processes of Referral... Information After Acceptance... The Nature of the Technique... The Safety of the Technique... The Degree of Disruption to the Patient's Life... The Waiting... Information on Admission to Hospital... The Brochure... The Day Before... The Day of Treatment... Follow -Up... Benign Tumours... Malignant Gliomas... Metastases... AVMs... Other Follow Up Measurements... Conclusion...
Contents Part I11 The Gamma Knife and Specific Diseases: Tumours 13 Vestibular Schwannomas... 123 Unilateral Vestibular Schwannomas: History and Microsurgery... 123 Introduction... 123 Debates About Function After Treatment... 124 Unilateral Vestibular Schwannomas: Gamma Knife Neurosurgery... 126 Gamma Knife and Vestibular Schwannomas... 126 The Early Days... 127 Current Gamma Knife Treatment... 127 Tumour Control... 129 Possible Complications and Problems... 130 Quality of Life... 134 Gamma Knife or Microsurgery... 135 Intracanalicular Vestibular Schwannomas... 135 Large Vestibular Schwaonomas... 136 Patients with Bilateral Tumours... 137 Neurofibromatosis 2... 137 Addendum Related to Dosimetry... 138 References... 138 14 Meningiomas... 145 Introduction... 145 Natural History of Meningiomas... 146 Contribution of Computerised Imaging... 146 Factors Concerning Who When and How to Treat Intracranial Meningiomas... 147 Tumour Size... 147 Patient Age and General Health... 147 Decision Making in the Treatment of Meningiomas: To Treat or Not to Treat... 147 Radicality of Surgery... 148 Turnour Location and Its Effect on Choice of Treatment... 149 Changing Technology and the Effect on Surgical Mortality... 149 The Morbidity and Mortality of Microsurgery and GKNS... 150 Other Factors that Are Relevant to the Choice of Treatment... 150 Results of Microsurgery Compared with GKNS... 154 How to Improve the Results... 155
Optic Nerve Sheath Meningiomas... Malignant Change... Conclusion...... References 15 Gamma Knife for Cerebral Metastases... Preamble About Problems... Concepts Scales and Parameters for Evidence Based Treatment... Phases of Clinical Trials (Institute of Cancer Research)... Ranking of Evidence... Karnowsky Score... Parameters Concerned in the Management of BMs are Listed Below... Recursive Partition Analysis (RPA) of the RTOG... Score Index for Stereotactic Radiosurgery for Brain Metastases (SIR)... Basic Score for Brain Metastases (BS-BM)... Graded Prognostic Assessment (GPA)... Background... The Size of the Problem... The Evolution of Imaging Techniques... Development of Treatment Methods... The Introduction of Radiosurgery... End Point of Treatment... Treatment-Related Complications Principles... Treatment Strategies for BMs... Should Up Front WBRT Be Used in All Patients?... The Effect of Dose on Results and Complications... Practical Treatment... Referral... Acceptance... Admission... Day of Treatment... Follow up... Routines... Complications... Conclusions...... References... Introduction... Gliomas... Classification... Gamma Knife Treatment of Glioma... Gliomas Conclusions... 16 Intraparenchymal Intrinsic Brain Tumours
Other Tumours Arising from Cerebral Tissue... 207 Choroid Plexus Papillomas... 207 Ependy momas... 207 Medulloblastomas... 208 Pineal Region Tumours... 208 Neurocytoma... 212 Haemangioblastoma... 212 References... 213 17 Tumours of the Pituitary Region... Pituitary Adenomas... Introduction and a Little Surgical History... GKNS Reminiscences... Some General Principles... Cushing's Disease... Acromegaly... Prolactinomas... Macroadenomas... Nelson's Syndrome... Craniopharyngiomas... Introduction... Case Selection... Results of Treatment... Conclusion... References... 18 Less Common Skull Base Tumours... 239 Introduction... 239 Benign Skull Base Turnours... 239 Non-vestibular Schwannoms... 239 Glomus Jugulare Tumor... 242 Malignant Skull Base Tumours... 245 Adenoid Cystic Carcinoma... 245 Chondrosarcornas and Chordomas... 246 Neuroblastoma... 247 List of Diagnoses Limited to Case Reports... 248 References... 248 Part IV The Gamma Knife and Specific Diseases: Vascular Diseases 19 Gamma Knife for Cerebral Vascular Anomalies... 255 Introduction... 255 Preamble About Principles... 255 General Principles of Treatment... 256 Principles of Gamma Knife Treatment... 259
Attempts to Predict Obliteration Rates... Prescription Dose x Volume x 113... Attempts to Predict and Manage Complication Rates... Adverse Radiation Effects (ARES)... Part V Ways of Calculating the Risk of Complications: Post Treatment Assessments The Linear Form...... The Exponential Form... Ways of Calculating the Risk of Complications: Pre-treatment Assessments... How GKNS Works on AVMs: Changes in Arteries Following Radiation... Patient Assessment for Gamma Knife Surgery... Informing the Patient (Family) Day of Treatment... Follow Up... Treatment Failure... Repeated Treatment Large AVMs Combined Treatments... Endovascular Treatment............ Gamma Knife for Cerebral Cavernous Malformations... Natural History... Summary of Relevant Natural &story... Therapy of CMs... Conclusions About CMs... Gamma Knife for Dural Arteriovenous Fistulae... Cerebral Developmental Venous Anomalies... References... The Gamma Knife and Specific Diseases: Functional Indications Contents... Introduction... Classical Trigeminal Neuralgia... Symptomatic Trigerninal Neuralgia... Pathology and Pathophysiology... Treatment Principles... A Vital Principle... Aim of Treatment... Medical Treatment... The Development of Interventional Treatments... Classification... Failure of Medical Treatment... Effects of Open Surgery... 20 Trigeminal Neuralgia
Gamma Knife Treatment... Introduction... The Mechanism by Which GKNS Can Affect Trigeminal Neuralgia... Development of Radiosurgery for Use with Trigeminal Neuralgia... GKNS Technique in the Treatment of Trigeminal Neuralgia... Secondary Trigeminal Neuralgia and Atypical Facial Pain... Conclusions... The Nature of GKNS Treatment... MVC and MVD... Considerations About the Sequence of Lnterventional Treatments for Trigeminal Neuralgia... References... 21 Diverse Functional Indications... Introduction... Parkinson's Disease and Essential Tremor... Epilepsy... Epilepsy Associated with Treatment Aimed Primarily at a Visible Lesion... Epilepsy Where the Epilepsy is the Reason for Treatment... Pain... Intracranial Pain Syndromes... Extracranial Pain Syndromes... Psychosurgery... References... Part VI The Gamma Knife and Specific Diseases: Less Common Indications 22 Rare Tumours and Other Lesions... 349 Introduction... 349 Hemangiopericytoma... 349 Lymphoma... 350 Rare Conditions Where the Information Is Based on Case Reports... 351 References... 351 23 Orbital Indications... 353 Introduction... 353 Uveal Melanomas Background Information... 353
Treatment Technique... Case Selection... Results in Terms of Local Control... Complications... Conclusion... Choroidal Haemangioma... Glaucoma... Optic Nerve Gliomas and Optic Nerve Sheath Meningiomas... Rare Conditions Where the Information is Based on Case Reports... References... Contents Part VII Conclusions 24 Conclusion and Possible Future Trends... Introduction... The Responsible Physician... The Therapeutic Team... Team Members with Treatment Expertise Would Have to Include... Team Members Who Refer and Follow Up Might Include... Functions of the Team... Personal Radiosensitivity: A Concluding Remark... Appendix A: A Simple Unassisted Frame Application... Index...