Change search
ReferencesLink to record
Permanent link

Direct link
Investigating the Clinical Aspects of Using CT vs. CT-MRI Images During Organ Delineation and Treatment Planning in Prostate Cancer Radiotherapy
Stockholm University, Faculty of Science, Department of Physics.
Show others and affiliations
2011 (English)In: Technology in Cancer Research & Treatment (Trykt), ISSN 1533-0346, Vol. 10, no 3, 231-242 p.Article in journal (Refereed) Published
Abstract [en]

In order to apply highly conformal dose distributions, which are characterized by steep dose fall-offs, it is necessary to know the exact target location and extension. This study aims at evaluating the impact of using combined CT-MRI images in organ delineation compared to using CT images alone, on the clinical results. For 10 prostate cancer patients, the respective CT and MRI images at treatment position were acquired. The CTV was delineated using the CT and MRI images, separately, whereas bladder and rectum were delineated using the CT images alone. Based on the CT and MRI images, two CTVs were produced for each patient. The mutual information algorithm was used in the fusion of the two image sets. In this way, the structures drawn on the MRI images were transferred to the CT images in order to produce the treatment plans. For each set of structures of each patient, IMRT and 3D-CRT treatment plans were produced. The individual treatment plans were compared using the biologically effective uniform dose (D) and the complication-free tumor control probability (R) concepts together with the DVHs of the targets and organs at risk and common dosimetric criteria. For the IMRT treatment, at the optimum dose level of the average CT and CT-MRI delineated CTV dose distributions, the P. values are 74.7% in both cases for a D(CTV) of 91.5 Gy and 92.1 Gy, respectively. The respective average total control probabilities, P(B) are 90.0% and 90.2%, whereas the corresponding average total complication probabilities, P, are 15.3% and 15.4%. Similarly, for the 3D-CRT treatment, the average P. values are 42.5% and 46.7%, respectively for a D(CTV) of 86.4 Gy and 86.7 Gy, respectively. The respective average PB values are 80.0% and 80.6%, whereas the corresponding average P values are 37.4% and 33.8%, respectively. For both radiation modalities, the improvement mainly stems from the better sparing of rectum. According to these results, the expected clinical effectiveness of IMRT can be increased by a maximum Delta P, of around 0.9%, whereas of 3D-CRT by about 4.2% when combined CT-MRI delineation is performed instead of using CT images alone. It is apparent that in both IMRT and 3D-CRT radiation modalities, the better knowledge of the CTV extension improved the produced dose distribution. It is shown that the CTV is irradiated more effectively, while the complication probabilities of bladder and rectum, which is the principal organs at risk, are lower in the CT-MRI based treatment plans.

Place, publisher, year, edition, pages
2011. Vol. 10, no 3, 231-242 p.
Keyword [en]
Prostate cancer radiotherapy, CT-MRI images, Radiobiological measures, Organ delineation
National Category
Physical Sciences
URN: urn:nbn:se:su:diva-68137ISI: 000290553700003OAI: diva2:472036
authorCount :10Available from: 2012-01-03 Created: 2012-01-03 Last updated: 2012-01-03Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Mavroidis, P.
By organisation
Department of Physics
In the same journal
Technology in Cancer Research & Treatment (Trykt)
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 14 hits
ReferencesLink to record
Permanent link

Direct link