TECHNICAL REPORTS SERIES No. 57 Computer Calculation of Dose Distributions in Radiotherapy INTERNATIONAL ATOMIC ENERGY AGENCY,VIENNA, 1966 COMPUTER CALCULATION OF DOSE DISTRIBUTIONS IN RADIOTHERAPY The following States ate Members of the International Atomic Energy Agency: AFGHANISTAN GABON NICARAGUA ALBANIA GERMANY, FEDERAL NIGERIA ALGERIA REPUBLIC OF NORWAY ARGENTINA GHANA PAKISTAN AUSTRALIA GREECE PANAMA AUSTRIA GUATEMALA PARAGUAY BELGIUM HAITI PERU BOLIVIA HOLY SEE PHILIPPINES BRAZIL HONDURAS POLAND' BULGARIA HUNGARY PORTUGAL BURMA ICELAND ROMANIA BYELORUSSIAN SOVIET INDIA SAUDI ARABIA SOCIALIST REPUBLIC INDONESIA SENEGAL CAMBODIA IRAN SOUTH AFRICA CAMEROON IRAQ SPAIN CANADA ISRAEL SUDAN CEYLON ITALY SWEDEN CHILE IVORY COAST SWITZERLAND CHINA JAMAICA SYRIAN ARAB REPUBLIC COLOMBIA JAPAN THAILAND CONGO, DEMOCRATIC JORDAN TUNISIA REPUBLIC OF KENYA TURKEY COSTA RICA KOREA, REPUBLIC OF UKRAINIAN SOVIET SOCIALIST CUBA KUWAIT REPUBLIC CYPRUS LEBANON UNION OF SOVIET SOCIALIST CZECHOSLOVAK SOCIALIST LIBERIA REPUBLICS REPUBLIC LIBYA UNITED ARAB REPUBLIC DENMARK LUXEMBOURG UNITED KINGDOM OF GREAT DOMINICAN REPUBLIC MADAGASCAR BRITAIN AND NORTHERN ECUADOR MALI IRELAND EL SALVADOR MEXICO UNITED STATES OF AMERICA ETHIOPIA MONACO URUGUAY FINLAND MOROCCO VENEZUELA FRANCE . NETHERLANDS VIET-NAM NEW ZEALAND YUGOSLAVIA The Agency's Statute was approved on 23 October 1956 by the Conference on the Statute of the IAEA held at United Nations Headquarters, New York; it entered into force on 29 July 1957. The Headquarters of the Agency are situated in Vienna. Its principal objective is "to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world". © IAEA, 1966 Permission to reproduce or translate the information contained in this publication may be obtained by writing to the International Atomic Energy Agency, KSrntner Ring 11, Vienna I, Austria. 1 Printed by the IAEA in Austria June 1966 TECHNICAL REPORTS SERIES No. 57 COMPUTER CALCULATION OF DOSE DISTRIBUTIONS IN RADIOTHERAPY REPORT OF A PANEL HELD IN VIENNA 18-22 OCTOBER 1965 INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 1966 International Atomic Energy Agency. Computer calculation of dose distributions in radiotherapy. Report of a Panel held in Vienna, 18 - 22 October 1965. Vienna, the Agency, 1966. 215 p. (IAEA, Technical reports series no. 57) 615.849 681.3 ' COMPUTER CALCULATION OF DOSE DISTRIBUTIONS IN RADIOTHERAPY, IAEA, VIENNA, 1966 STI/DOC/lO/57 FOREWORD As in most areas of scientific endeavour, the advent of electronic com- puters has made a significant impact on the investigation of the physical aspects of radiotherapy. Since the first paper on the subject was published in 1955 the literature has rapidly expanded to include the application of com- puter techniques to problems of external beam, and intracavitary and inter- stitial dosimetry. By removing the tedium of lengthy repetitive calculations, the availability of automatic computers has encouraged physicists and radio- therapists to take a fresh look at many fundamental physical problems of radiotherapy. The most important result of the automation of dosage calcu- lations is not simply an increase in the quantity of data but an improvement in the quality of data available as a treatment guide for the therapist. In October 1965 the International Atomic Energy Agency convened a panel in Vienna on the "Use of Computers for Calculation of Dose Distribu- tions in Radiotherapy" to assess the current status of work, provide guide- lines for future research, explore the possibility of international co- operation and make recommendations to the Agency. The panel meeting was attended by 15 participants from seven countries, one observer, and two representatives of the World Health Organization. Participants contributed 20 working papers which served as the bases of discussion. By the nature of the work, computer techniques have been developed by a few advanced centres with access to large computer installations. How- ever, several computer methods are now becoming "routine" and can be used by institutions without facilities for research. It is hoped that the report of the Panel will provide a comprehensive view of the automatic com- putation of radiotherapeutic dose distributions and serve as a means of com- munication between present and potential users of computers. CONTENTS INTRODUCTION AND REPORT INTRODUCTION 3 REPORT ON PROCEEDINGS OF THE PANEL 9 1. Production of isodose charts for single, multiple and moving beams 9 2. Provision of corrections for body shape and tissue inhomogeneity 11 3. Sealed source calculations 12 4. Presentation and evaluation of results '.. 14 5. Economics 18 6. Organization and international co-operation 19 7. Philosophy and future 23 8. Recommendations 24 WORKING PAPERS 1. Single field distribution derived by theoretical methods as compared with empirical data 2 7 T. D. Sterling 2. Computation of dose distributions using wedge and compensating filters: correction for irregular body contours 36 J. van de Geijn 3. Computation of multiple and moving beam'distributions 53 J. R. Cunningham 4. Computer-assisted external-beam dosimetry with special reference to correction calculations and presentation of data . 63 J.S. Clifton 5. Correction of single-field distributions to allow for tissue inhomogeneity 74 Aê Dutreix 6. Effect of tissue inhomogeneities on external radiation therapy dose distributions 79 W. Siler and C. Dymytryshak 7. Computer calculations in interstitial seed therapy: I. Radiation treatment planning 83 II. Dose control after seed implantation 92 M. Busch 8. Automatic calculation of isodose curves from implants of radiation sources 100 С,. W. Batten and R.J. Shalek 9. Calculation of dose distributions for multi-field and moving beam irradiations and methods of presenting results 107 G. Schoknecht 10. The optimization of treatment plans 118 C.S. Hope, M.J.E. Laurie and J. S. Orr 11. Clinical evaluation of treatment plans: Criteria used to select optimum plan 129 H. Perry ; ; 12. Economics of computer dosimetry 146 I. Ragnhult 13. Systematic study of therapeutic radiation dose distributions ... 151 К. C. Tsien . ' ' 14. Evaluation of integral absorbed dose and other physical parameters characterizing the radiation field in external radiotherapy 157 I. Ragnhult 15. Organization of a computer facility in a hospital physics department 164 W. Siler 16. International co-operation in the use of computers 167 К. C. Tsien ' 17. Transmission of data: Digital processing of isodose patterns .. 168 К. C. Tsien 18. International co-operation in use of computers 171 T. D. Sterling 19. Clinical evaluation of treatment plans 177 E.W. Emery 20. Physicist or computer specialist? 182 BIBLIOGRAPHY 187 APPENDIX I: Glossary ...: 197 APPENDIX II: Questionnaire on use of computers for calculation of dose distributions in radiotherapy 201 APPENDIX III: Institutions using computers for dosimetric calculations in radiotherapy • • 211 LIST OF PARTICIPANTS 213 INTRODUCTION AND REPORT INTRODUCTION During the past few years there has been a rapid development in the use of automatic digital computers in radiotherapy. Several hospitals, par- ticularly in the United States of America, are using such computers for routine treatment planning both in teletherapy and in interstitial and intra- cavitary therapy. Many other hospitals are acquiring their own computers or are arranging for access to an outside computer. These facilities are not necessarily intended, or even suitable, for dosimetric purposes in radio- therapy since there are various other uses for a computer in a hospital, e.g. payroll, inventory, documentation. However, it is probable that many hospi- tals would be interested in the dosimetric applications if the advantages of computers in this field were more widely known. Furthermore, even where a hospital has no prospect of acquiring computing facilities in the near future - as in most developing countries - it should at least be aware of the wide range of useful radiotherapeutic data that could be made available by other institutes which are using computers in this field. A small panel of physicists, radiotherapists and computer specialists, drawn from 7 countries, was convened in Vienna from 18 to 22 October 1965. The purpose of the meeting was to review the present position with regard to the use of digital computers for calculating dose distributions in radio- therapy, to consider possible future developments, and to make recom- mendations both to those working in the field and to the International Atomic Energy Agency. (The Panel did not feel itself competent to discuss analogue computers in detail, although it was aware that such machines have a poten- tially useful role in radiotherapy. ) A number of working papers on different aspects of the subject were prepared by the participants and were distributed in advance of the meeting. These papers were not presented formally, but served as background ma- terial and as a basis for discussion. Edited versions of the working papers are appended to the present publication, except for those which have since been published in scientific journals. The discussions of the Panel, occupying five working days, were too lengthy to reproduce verbatim. The present volume therefore contains only a summary report of the discussions which nevertheless, we hope, includes all the highlights and will convey a little of the meat and flavour of the ex- changes as well as the bare bones. Since the conclusion of the meeting two additional