- Email: [email protected]
Dosimetric Evaluation in Heterogeneous Tissue of Anterior Electron Beam Irradiation for Treatment of Retinoblastoma
Literature Reviews This article describes the results of the clinical use of the SISGARD computer system at the Antine-Lacassagne Cancer for a four year period. SISGARD consists of a series of microcomputers connected to a common mass memory; each microcomputer is used as an intelligent console, SISGARD is in charge of surveillance of the radio therapy treatments given by the Center’s three radio therapy units. It is also used for administrative purposes in the Department and physically connects all of the Departments’ operating stations. SISGARD was developed to guarantee that the treatments comply with prescriptions, to supply dosimetric data, to improve administrative work and to supply banks with data for statistical analysis and research.
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shown that to use MRI data for treatment planning one must; (a) use careful patient positioning and marking, (b) transfer information from CT to MRI and vice versa, (c) determine the geometrical consistency between the CT and MRI data sets, (d) investigate the unwarping of distorted MR images, and (e) have the ability to use non-axial images for determination of beam treatment technique, dose calculations, and plan evaluation.
AN ENDOCAVITYRECTAL IRRADIATIONTECHNIQUE Ervin B. Podgorsak, Ph.D., FCCPM, and Michael D.C. Evans, M.Sc., MCCPM Department of Radiation Oncology, Sir Mortimer B. Davis Jewish General Hosp. and McGill University, 3755 Chemin de la Cote Ste Catherine, Montreal, Quebec, H3TIE2 Canada
A COMPUTER-AIDEDTREATMENT PLANNING TECHNIQUE FOR UNIVERSALWEDGES C.W. Cheng, Ph.D., and L.M. Chin, D.Sc. Joint Center for Radiation Therapy and Department Radiation Therapy, Harvard Medical School, 44 Binney St., Boston, MA 02 115
of
International Journal of Radiation Oncology, Biology, Physics Dec. 1987, Vol. 13, pp. 1927-1935 Some modern accelerators have a wedge built into the head of the treatment machine. It is designed to provide a large dose gradient across the treatment field. The wedge angle is usually about 60” at a depth of 10 cm for a 10 X 10 cm2 field. Smaller wedge angles can be obtained by combining wedged and unwedged beams in various proportions. This technique is often referred to as the “universal wedge.” There are several methods to calculate the contributions of wedged and open fields for a given wedge angle in a water phantom. However, it is often difficult to determine what effective wedge angles should be used in a multiple static field treatment for an irregular contour. A computer algorithm has been developed to aid the treatment planner with this problem so the “universal wedge” principle can be efficiently applied.
International Journal of Radiation Oncology, Biology, Physics Dec. 1987, Vol. 13, pp. 1937-1941 The standard technique for rectal irradiation consists of a short target skin distance, with the insertion of the x-ray tube into the proctoscopic cone and using a hand held cone and tube operation. This technique presents several disadvantages; (1) the possibility of motion during treatment which can cause a geographic miss of tumor and (2) the relatively high occupational dose to the staff members performing the hand held operation. However. the technique developed at McGill makes use of a relatively long targetskin distance and a proctoscopic cone which is linked to the superficial x-ray tube with an electomagnetic lock. The proctoscopic cone is immobilized by a hydraulic clamp which reduces the possibility of a geographic miss. This technique should be considered as an alternative in departments in which the superficial x-ray unit is not designed for the insertion of proctoscopic cones.
MICHAEL
DWORZANIN
INTEGRATIONOF MAGNETIC RESONANCEIMAGING INTO RADIATION THERAPY TREATMENT PLANNING. I. TECHNICALCONSIDERATIONS
DOSIMETRICEVALUATIONIN HETEROGENEOUSTISSUE OF ANTERIOR ELECTRONBEAM IRRADIATIONFOR TREATMENTOF RETINOBLASTOMA
B.A. Fraass, Ph.D., D.L. McShan,Ph.D., R.F. Diaz, M.D.. R.K. Ten Haken, Ph.D., A. Aisen, M.D., S. Gebarski, M.D., G. Glazier, M.D. and A.S. Lichter, M.D.
Steven M. Kirsner, Kenneth R. Hogstrom, Rajendra G. Kurup, and Michael F. Moyers Department of Radiation Physics, The University of Texas M.D. Anderson Hospital and Tumor Institute
University of Michigan Medical Center, Ann Arbor, MI 48 109
Medical Physics, Volume 14, No. 5, September/October 1987, 772-779
International Journal of Radiation Oncology, Biology, Physics Dec. 1987, Vol. 13, pp. 1897-1908
This paper presents an alternative technique from the lateral photon beam treatment of retinoblastoma. The study considers an anterior electron beam aimed directly at the eye with a small block shielding the lens. The work includes evaluating the influence of the eye’s irregular surface contour and adjacent bony anatomy. Computer generated dose
This article presents the results of a study in which the feasibility of using Magnetic Resonance Imaging in radiation therapy treatment planning is addressed. The study has
44
Medical Dosimetry
distributions of a pencil beam algorithm are compared to measured data. It was concluded that three-dimensional heterogeneity correction and an algorithm which accounts for bremsstrahlung production within the lens block are essential to improve accuracy of dose distributions. The study showed that the anterior portion of the retina was best treated with the anterior electron beam and the posterior portion of the retina was best treated with lateral photon beam.
EFFECTS OFFINITEANGULARSTEPSAND EXTENTOF PROFILE DATA ON THECALCULATION OF ROTATIONAL X-RAY DOSE DISTRIBUTIONS
Volume 13, Number 1, 1988
Department of Medical Physics, Memorial SloanKettering Cancer Center, New York, NY 1002 1 Medical Physics, Volume 14, No. 6, November/December 1987, 1048-1052 Dose volume histograms (DVHs) are a quick and easy way to evaluate three-dimensional dose distribution data. An algorithm has been developed to determine DVHs for single anatomic structures as well as for combinations of structures. The user chooses a hierarchy in order to distinguish each anatomic structure. This enables areas of overlapping structures to be separated and DVHs calculated for each individual structure. Then the algorithm can add or subtract the individual histograms. An example is presented to illustrate these operations.
R.G. Kurup, K.R. Hogstrom, and C.C. Hwang Department of Radiation Physics, University of Texas, M.D. Anderson Hospital and Tumor Institute, Houston, TX 77030 Medical Physics, Volume 14, No. 6, November/December 1987, 1053-1055 A comparison was performed evaluating the accuracy of the rotational beam algorithm using the Bentley beam model in the General Electric RT/Plan or Target treatment planning system. Dose calculations from the computer were compared with measured data for an 18-MV x-ray beam. The study showed that the Bentley beam model, which excludes the tails of the beam profile, with fixed beams calculated at 10’ intervals predicted dose in the treatment volume with an accuracy of 2%. Doses to tissues at shallow depths were shown to be underestimated up to 10% or more which corresponds to 2% to 3% of the dose at the isocenter. It was then demonstrated the inclusion of data from 3 to 4 centimeters more of the tail of the beam profile and using a maximum dose calculational step of 5” provided a method for predicting doses with less than 5% error at shallower depths. Near the isocenter all methods gave the same result.
A TECHNIQUE FORCOMPUTING DOSEVOLUME HISTOGRAMS FORSTRUCTURE COMBINATIONS Radhe Mohan, Linda J. Brewster,and Glenn D. Barest
INTRACAVITARY IRRADIATION OF ENDOMETRIAL CANCEROF LARGEUTERIUSINGA TWO-PHASE AFTERLOADING TECHNIQUE Antti Kauppila, M.D., Pirkko Sipila, M.D.
and Antero Koivula, Ph.D. Departments of Obstetrics and Gynecology, and Radiotherapy, University of Oulu, Finland The British Journal of Radiology, Volume 60, November 1987, 1093-1097 When treating endometrial cancer with an afterloading Cathetron, a single source tandem is unable to deliver a homogeneous dose to the walls of a uterus which is greater than 9 cm long. Employing a custom made insertion instrument for the precise placement of the in&a-uterine radioactive sources will resolve this problem. The special insertion catheter assumes a “V” shape appearance. Only one lateral half of the uterine body was treated during each part of the two-phase technique. The treatment utilizes two cobalt sources in the Cathetron remote afterloading unit. Early clinical results are discussed employing this technique in cases of uterine lengths varying from 10 cm to 16 cm in 34 patients. Preliminary findings indicate results comparable to the Heyman packing method without the radiation hazards when using this afterloading technique.
43
shown that to use MRI data for treatment planning one must; (a) use careful patient positioning and marking, (b) transfer information from CT to MRI and vice versa, (c) determine the geometrical consistency between the CT and MRI data sets, (d) investigate the unwarping of distorted MR images, and (e) have the ability to use non-axial images for determination of beam treatment technique, dose calculations, and plan evaluation.
AN ENDOCAVITYRECTAL IRRADIATIONTECHNIQUE Ervin B. Podgorsak, Ph.D., FCCPM, and Michael D.C. Evans, M.Sc., MCCPM Department of Radiation Oncology, Sir Mortimer B. Davis Jewish General Hosp. and McGill University, 3755 Chemin de la Cote Ste Catherine, Montreal, Quebec, H3TIE2 Canada
A COMPUTER-AIDEDTREATMENT PLANNING TECHNIQUE FOR UNIVERSALWEDGES C.W. Cheng, Ph.D., and L.M. Chin, D.Sc. Joint Center for Radiation Therapy and Department Radiation Therapy, Harvard Medical School, 44 Binney St., Boston, MA 02 115
of
International Journal of Radiation Oncology, Biology, Physics Dec. 1987, Vol. 13, pp. 1927-1935 Some modern accelerators have a wedge built into the head of the treatment machine. It is designed to provide a large dose gradient across the treatment field. The wedge angle is usually about 60” at a depth of 10 cm for a 10 X 10 cm2 field. Smaller wedge angles can be obtained by combining wedged and unwedged beams in various proportions. This technique is often referred to as the “universal wedge.” There are several methods to calculate the contributions of wedged and open fields for a given wedge angle in a water phantom. However, it is often difficult to determine what effective wedge angles should be used in a multiple static field treatment for an irregular contour. A computer algorithm has been developed to aid the treatment planner with this problem so the “universal wedge” principle can be efficiently applied.
International Journal of Radiation Oncology, Biology, Physics Dec. 1987, Vol. 13, pp. 1937-1941 The standard technique for rectal irradiation consists of a short target skin distance, with the insertion of the x-ray tube into the proctoscopic cone and using a hand held cone and tube operation. This technique presents several disadvantages; (1) the possibility of motion during treatment which can cause a geographic miss of tumor and (2) the relatively high occupational dose to the staff members performing the hand held operation. However. the technique developed at McGill makes use of a relatively long targetskin distance and a proctoscopic cone which is linked to the superficial x-ray tube with an electomagnetic lock. The proctoscopic cone is immobilized by a hydraulic clamp which reduces the possibility of a geographic miss. This technique should be considered as an alternative in departments in which the superficial x-ray unit is not designed for the insertion of proctoscopic cones.
MICHAEL
DWORZANIN
INTEGRATIONOF MAGNETIC RESONANCEIMAGING INTO RADIATION THERAPY TREATMENT PLANNING. I. TECHNICALCONSIDERATIONS
DOSIMETRICEVALUATIONIN HETEROGENEOUSTISSUE OF ANTERIOR ELECTRONBEAM IRRADIATIONFOR TREATMENTOF RETINOBLASTOMA
B.A. Fraass, Ph.D., D.L. McShan,Ph.D., R.F. Diaz, M.D.. R.K. Ten Haken, Ph.D., A. Aisen, M.D., S. Gebarski, M.D., G. Glazier, M.D. and A.S. Lichter, M.D.
Steven M. Kirsner, Kenneth R. Hogstrom, Rajendra G. Kurup, and Michael F. Moyers Department of Radiation Physics, The University of Texas M.D. Anderson Hospital and Tumor Institute
University of Michigan Medical Center, Ann Arbor, MI 48 109
Medical Physics, Volume 14, No. 5, September/October 1987, 772-779
International Journal of Radiation Oncology, Biology, Physics Dec. 1987, Vol. 13, pp. 1897-1908
This paper presents an alternative technique from the lateral photon beam treatment of retinoblastoma. The study considers an anterior electron beam aimed directly at the eye with a small block shielding the lens. The work includes evaluating the influence of the eye’s irregular surface contour and adjacent bony anatomy. Computer generated dose
This article presents the results of a study in which the feasibility of using Magnetic Resonance Imaging in radiation therapy treatment planning is addressed. The study has
44
Medical Dosimetry
distributions of a pencil beam algorithm are compared to measured data. It was concluded that three-dimensional heterogeneity correction and an algorithm which accounts for bremsstrahlung production within the lens block are essential to improve accuracy of dose distributions. The study showed that the anterior portion of the retina was best treated with the anterior electron beam and the posterior portion of the retina was best treated with lateral photon beam.
EFFECTS OFFINITEANGULARSTEPSAND EXTENTOF PROFILE DATA ON THECALCULATION OF ROTATIONAL X-RAY DOSE DISTRIBUTIONS
Volume 13, Number 1, 1988
Department of Medical Physics, Memorial SloanKettering Cancer Center, New York, NY 1002 1 Medical Physics, Volume 14, No. 6, November/December 1987, 1048-1052 Dose volume histograms (DVHs) are a quick and easy way to evaluate three-dimensional dose distribution data. An algorithm has been developed to determine DVHs for single anatomic structures as well as for combinations of structures. The user chooses a hierarchy in order to distinguish each anatomic structure. This enables areas of overlapping structures to be separated and DVHs calculated for each individual structure. Then the algorithm can add or subtract the individual histograms. An example is presented to illustrate these operations.
R.G. Kurup, K.R. Hogstrom, and C.C. Hwang Department of Radiation Physics, University of Texas, M.D. Anderson Hospital and Tumor Institute, Houston, TX 77030 Medical Physics, Volume 14, No. 6, November/December 1987, 1053-1055 A comparison was performed evaluating the accuracy of the rotational beam algorithm using the Bentley beam model in the General Electric RT/Plan or Target treatment planning system. Dose calculations from the computer were compared with measured data for an 18-MV x-ray beam. The study showed that the Bentley beam model, which excludes the tails of the beam profile, with fixed beams calculated at 10’ intervals predicted dose in the treatment volume with an accuracy of 2%. Doses to tissues at shallow depths were shown to be underestimated up to 10% or more which corresponds to 2% to 3% of the dose at the isocenter. It was then demonstrated the inclusion of data from 3 to 4 centimeters more of the tail of the beam profile and using a maximum dose calculational step of 5” provided a method for predicting doses with less than 5% error at shallower depths. Near the isocenter all methods gave the same result.
A TECHNIQUE FORCOMPUTING DOSEVOLUME HISTOGRAMS FORSTRUCTURE COMBINATIONS Radhe Mohan, Linda J. Brewster,and Glenn D. Barest
INTRACAVITARY IRRADIATION OF ENDOMETRIAL CANCEROF LARGEUTERIUSINGA TWO-PHASE AFTERLOADING TECHNIQUE Antti Kauppila, M.D., Pirkko Sipila, M.D.
and Antero Koivula, Ph.D. Departments of Obstetrics and Gynecology, and Radiotherapy, University of Oulu, Finland The British Journal of Radiology, Volume 60, November 1987, 1093-1097 When treating endometrial cancer with an afterloading Cathetron, a single source tandem is unable to deliver a homogeneous dose to the walls of a uterus which is greater than 9 cm long. Employing a custom made insertion instrument for the precise placement of the in&a-uterine radioactive sources will resolve this problem. The special insertion catheter assumes a “V” shape appearance. Only one lateral half of the uterine body was treated during each part of the two-phase technique. The treatment utilizes two cobalt sources in the Cathetron remote afterloading unit. Early clinical results are discussed employing this technique in cases of uterine lengths varying from 10 cm to 16 cm in 34 patients. Preliminary findings indicate results comparable to the Heyman packing method without the radiation hazards when using this afterloading technique.