| Autor: |
K Leysen, M. Boussaer, Dirk Verellen, M. De Ridder, Michael Duchateau, Thierry Gevaert, A. Gulyban, G.A. Storme, K Tournel, T. Depuydt, G. Soete, Kenneth Poels, T Reynders |
| Rok vydání: |
2011 |
| Předmět: |
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| Zdroj: |
Medical Physics. 38:3593-3593 |
| ISSN: |
0094-2405 |
| Popis: |
Purpose: Investigation of the technical feasibility and dosimetry of image‐ guided total marrow irradiation using helical TomoTherapy in the treatment of relapsed multiple myeloma patients. Irradiation is followed by a hematopietic stemcell transplantation. This study concentrates on planning and dosimetry Methods: Patients are simulated in supine position with H&N mask and pelvic cast. TomoTherapy plans for the upper body (head‐knees) were generated (pitch 0.45, modulation factor 2.0, field width 5cm). Dose prescription was 4x3Gy=12Gy. Dose verification is performed with the I'mRT MatriXX. Beam‐on‐time is +/−30min. TMI‐stability measurement was done with 2 ICs on different distances in 1.5m solid water equivalent blocks. Lower extremities were planned conventional and with TomoTherapy. Dose in the junction region between upper and lower body plans was verified with EDR2 film for both techniques. Results: It is possible to create clinically acceptable plans for the upper body with TomoTherapy. Verification shows acceptable results in the lung region (gamma 5%, 7mm). Measurement in pelvis region is less good as in lung region. TMI‐stability measurement shows differences in dose till 4% measured/calculated. During TMI a 2.5% dose drift was seen by the detectors. Plans for the extremities were more homogeneous in the junction region with TomoTherapy comparing with the conventional technique. Conclusions: TPS has difficulties to find a good ratio between couch and gantry speed. Differences seen at TMI‐stability measurements can be pointed to drift and stability of one rotation. Differences are depending on system stability (magnetron, target, …). Patient specific QA is necessary before treatment. Differences between the gamma index of the lungs and pelvis can be pointed to the fact that the planning is optimized very well for the lung region. Pitch and modulation factor are optimized for this region. For the junction region tomotherapy plans give a better homogeneity than 1 tomotherapy and 1 conventional plan. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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