Implication of CT table sag on geometrical accuracy during virtual simulation
| Autor: | Karl Prado, Andrew G. Lee, Richard Wu, Rajat J. Kudchadker, John R. Zullo |
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| Rok vydání: | 2007 |
| Předmět: |
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Dose delivery Offset (computer science) Radiological and Ultrasound Technology medicine.diagnostic_test Computer science Posture Normal tissue Isocenter Computed tomography Radiotherapy Dosage Patient Simulation Oncology Neoplasms Radiation oncology medicine Humans Radiology Nuclear Medicine and imaging Vertical displacement Tomography X-Ray Computed Simulation |
| Zdroj: | Medical dosimetry : official journal of the American Association of Medical Dosimetrists. 32(4) |
| ISSN: | 0958-3947 |
| Popis: | Computed tomography (CT) scanners are used in hospitals worldwide for radiation oncology treatment simulation. It is critical that the process very accurately represents the patient positioning to be used during the administration of radiation therapy to minimize the dose delivery to normal tissue. Unfortunately, this is not always the case. One problem is that some degree of vertical displacement, or sag, occurs when the table is extended from its base when under a clinical weight load, a problem resulting from mechanical limitations of the CT table. In an effort to determine the extent of the problem, we measured and compared the degree of table sag for various CT scanner tables at our institution. A clinically representative weight load was placed on each table, and the amount of table sag was measured for varying degrees of table extension from its base. Results indicated that the amount of table sag varied from approximately 0.7 to 6.6 mm and that the amount of table sag varied not only between tables from different manufacturers but also between tables of the same model from the same manufacturer. Failure to recognize and prevent this problem could lead to incorrectly derived isocenter localization and subsequent patient positioning errors. Treatment site-specific and scanner-based laser offset correction should be implemented for each patient’s virtual simulation procedure. In addition, the amount of sag should be measured under a clinically representative weight load upon CT-simulator commissioning. |
| Databáze: | OpenAIRE |
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