| 1. |
- Bäck, S A, et al.
(författare)
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Verification of single beam treatment planning using a ferrous dosimeter gel and MRI (FeMRI)
- 1998
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Ingår i: Acta Oncologica. - 0284-186X. ; 37:6, s. 6-561
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Tidskriftsartikel (refereegranskat)abstract
- A method for analysing and comparing treatment planning system (TPS) data and ferrous dosimeter gel measurements evaluated with MRI (FeMRI) was developed, including image processing to final absorbed dose images. Measurements were analysed according to this method and FeMRI data were thereby compared with the TPS-calculated dose distribution. For photons, differences between FeMRI- and TPS dose data were mainly within +/- 2%. Minor shortcomings found in both the FeMRI system and the TPS are explained and discussed. For electron beams, there was an overall good agreement. It was found that the TPS underestimates the lateral scattering dose outside the primary beam, but the reported dose difference corresponds to a small spatial deviation (less than 2 mm). It is important to consider this single beam data comparison when the method is extended to more complicated situations, for example when using several beams.
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| 2. |
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| 3. |
- Johansson, S A, et al.
(författare)
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Dosimeter gel and MR imaging for verification of calculated dose distributions in clinical radiation therapy
- 1997
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Ingår i: Acta Oncologica. - 0284-186X. ; 36:3, s. 90-283
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Tidskriftsartikel (refereegranskat)abstract
- A dosimeter gel, based on an agarose gel infused with a ferrous sulphate solution and evaluated in a magnetic resonance scanner, was used for complete verification of calculated dose distributions. Two standard treatment procedures, treatment of cancer in the urinary bladder and treatment of breast cancer after modified radical mastectomy, were examined using pixel-by-pixel and dose volume histogram comparison. The dose distributions calculated with the dose planning system was in very good agreement with the measured ones. However, in the case of the more complicated breast cancer treatment, some discrepancies were found, mainly at the beam abutment region. This may be explained by field displacements errors and by a small limitation of the dose planning utilising small electron beams in this region. The dosimeter gel system have proven to be a useful tool for dosimetry in clinical radiation therapy applications.
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| 4. |
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| 5. |
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| 6. |
- Bäck, Sven, et al.
(författare)
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Improvements in absorbed dose measurements for external radiation therapy using ferrous dosimeter gel and MR imaging (FeMRI)
- 1998
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 43, s. 261-
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Tidskriftsartikel (refereegranskat)abstract
- A ferrous gel, based on ferrous (Fe) sulphate and agarose, was used with a clinical magnetic resonance imaging (MRI) scanner to obtain relative dose distribution data from therapeutic photon and electron beams. The FeMRI gel was scanned using a new MRI acquisition protocol optimized for T1 measurements. Thorough comparisons with silicon semiconductor detector and ionization chamber measurements, as well as with Monte Carlo calculations, were performed in order to quantify the improvements obtained using FeMRI for dose estimations. Most of the relative doses measured with FeMRI were within 2% of the doses measured with other methods. The larger discrepancies (2-4%) found at shallow depths are discussed. The uncertainty in relative dose measurements using FeMRI was significantly improved compared with previously reported results (5-10%, one standard deviation, 1 SD), and is today between 1.6% and 3.3% (depending on dose level, 2 SD). This corresponds to an improvement in the minimum detectable dose (3 SD above background) from approximately 2 Gy to better than 0.6 Gy. The results obtained in this study emphasize the importance of obtaining basic FeMRI dose data before the method is extended to complicated treatment regimes.
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| 7. |
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| 8. |
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| 9. |
- Jonsson, A-K, et al.
(författare)
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Ionic and Electronic Conductivity in ZrO2
- 1999
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Ingår i: Joint International Meeting of the Electrochem.Soc., Honolulu, Oct 17-22.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 10. |
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