On-line set-up corrections during radiotherapy of patients with gynaecologic tumors
| Autor: | Merik Seven, Joep Stroom, Sandra Quint, Marjan de Hoog, Manouk J.J. Olofsen-van Acht, Hans C.J. de Boer, Carien L. Creutzberg, Andries G. Visser |
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| Přispěvatelé: | Radiotherapy, Pediatrics |
| Rok vydání: | 2000 |
| Předmět: |
Cancer Research
Time Factors Genital Neoplasms Female medicine.medical_treatment Planning target volume Standard deviation Set (abstract data type) Physical Phenomena medicine Humans Radiology Nuclear Medicine and imaging Female genitals Radiation treatment planning Experimental radiotherapy and neuro-oncology Radiation business.industry Physics Radiotherapy Planning Computer-Assisted Experimentele radiotherapie en neuro-oncologie Radiation therapy Oncology Line (geometry) Female Treatment time Radiotherapy Conformal Nuclear medicine business |
| Zdroj: | International Journal of Radiation Oncology, Biology, Physics, 46, 2, pp. 499-506 International Journal of Radiation Oncology, Biology, Physics, 46, 499-506 International Journal of Radiation Oncology Biology Physics, 46(2), 499-506. Elsevier Inc. |
| ISSN: | 0360-3016 |
| Popis: | Positioning of patients with gynecologic tumors for radiotherapy has proven to be relatively inaccurate. To improve the accuracy and reduce the margins from clinical target volume (CTV) to planning target volume (PTV), on-line set-up corrections were investigated.Anterior-posterior portal images of 14 patients were acquired using the first six monitor units (MU) of each irradiation fraction. The set-up deviation was established by matching three user-defined landmarks in portal and simulator image. If the two-dimensional deviation exceeded 4 mm, the table position was corrected. A second portal image was acquired using 30 MU of the remaining dose. This image was analyzed off-line using a semiautomatic contour match to obtain the final set-up accuracy. To verify the landmark match accuracy, the contour match was retrospectively performed on the six MU images as well.The standard deviation (SD) of the distribution of systematic set-up deviations after correction was1 mm in left-right and cranio-caudal directions. The average random deviation was2 mm in these directions (1 SD). Before correction, all standard deviations were 2 to 3 mm. The landmark match procedure was sufficiently accurate and added on average 3 min to the treatment time. The application of on-line corrections justifies a CTV-to-PTV margin reduction to about 5 mm.On-line set-up corrections significantly improve the positioning accuracy. The procedure increases treatment time but might be used effectively in combination with off-line corrections. |
| Databáze: | OpenAIRE |
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