scholarly journals Comparison of two planning techniques (FiF/IMRT) for postoperative radiation therapy of prostate cancer

2020 ◽  
Vol 48 (2-3) ◽  
pp. 47-53
Author(s):  
Nevena Obajdin ◽  
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Radiation Therapy ◽  
Organs At Risk ◽  
Planning Techniques ◽  
Dose Distributions ◽  
Dose Volume ◽  
Significant Difference ◽  
Target Volumes ◽  
Planning Technique

Introduction: Within the past two decades, we made significant progress in radiation therapy for prostate cancer. At UH Rijeka IMRT became the technique of choice for radiation therapy following radical prostatectomy since 2016. Previously, an advanced 3-DCRT technique using the field-in-field (FiF) method was used for dose distribution optimization around target volumes and organs-at-risk. This research has been performed to investigate the influence of planning technique choice (FiF or IMRT) on coverage of target volumes with prescribed dose and organs-at-risk sparing. Materials and methods: Comparison of dose distributions calculated using FiF and IMRT techniques was performed retrospectively for ten patients who underwent postoperative radiotherapy. The prescribed dose for all patients was delivered using IMRT, and for this research, we also calculated dose distributions using the FiF technique. For FiF and IMRT techniques, we used linear accelerator photon beams. To determine the influence of planning technique on dose distribution parameters related to target volumes (GTV, CTV, PTV1, PTV2) were analyzed. For organs-at-risk sparing evaluation (rectum, bladder, femoral heads), we used dose-volume constraints. Results and discussion: The analysis of parameters related to target volumes has shown that most of them had no statistically significant difference (V100%(GTV), V100%(CTV), V95%(PTV2), V95%(PTV1)). For both planning techniques, internationally set dose constraints were achieved. Statistically, we found a significant difference for V100%(PTV2), p=0,000534, and V100%(PTV1), p=0,042944 in favor of IMRT. A statistically significant difference (p=0,045966) was found for the volume of the rectum, which receives 40Gy, and for the volume of femoral heads, which receives 30Gy (p=0,000385), where the sparing is better for IMRT. For dose-volume constraints related to the bladder, no statistically significant differences were found. Conclusion: Results of this research show a statistically significant difference for V100% target volume coverage for PTV1 and PTV2, with better dose coverage accomplished by IMRT. Concerning organs-at-risk sparing, a statistically significant difference in favor of IMRT was found for rectum volume, which receives 40Gy. Expectedly, IMRT was superior to the FiF technique. However, differences between the two planning techniques were relatively small, which points to the fact that the FiF technique is viable as a technique of choice.

Reduction of Dose Delivered to Organs at Risk in Prostate Cancer Patients via Image-Guided Radiation Therapy

2010 ◽  
Vol 76 (3) ◽  
pp. 924-934 ◽  
Author(s):  
Jason M. Pawlowski ◽  
Eddy S. Yang ◽  
Arnold W. Malcolm ◽  
Charles W. Coffey ◽  
George X. Ding
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Radiation Therapy ◽  
Cancer Patients ◽  
Organs At Risk ◽  
Image Guided Radiation Therapy ◽  
Image Guided

Retrospective dosimetric evaluation of VMAT plans for prostate cancer treatment

2018 ◽  
Vol 18 (02) ◽  
pp. 155-164 ◽  
Author(s):  
Johnson Darko ◽  
Ernest Osei ◽  
Andre Fleck ◽  
Ramana Rachakonda
Keyword(s):  
Prostate Cancer ◽  
Radiation Therapy ◽  
Cancer Treatment ◽  
Planning Process ◽  
Organs At Risk ◽  
Locally Advanced ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Prostate Cancer Treatment ◽  
Target Volumes

AbstractBackgroundRadiation therapy (RT) remains a common and effective treatment modality for patients with locally advanced prostate cancer. Technological advancements over the past decade have resulted in the introduction of intensity-modulated radiation therapy (IMRT) planning and delivery techniques that maximise the dose of radiation delivered to the prostate while sparing organs at risk (OAR). A more recent and evolving IMRT technique, called volumetric-modulated arc therapy (VMAT), involves a continuous irradiation at a constant or variable dose rate when the gantry rotates around the prostate using one or more arcs.Materials and methodsThis paper reports on a dosimetric evaluation of our implementation of VMAT technique for prostate cancer treatment. A retrospective analysis of VMAT plans was performed for 300 prostate cancer patients treated during the period of January 2013 to December 2014. Two prescription cohorts of patients treated to a dose of 78 Gy in 39 fractions as the primary radiation therapy treatment (XRT) and 66 Gy in 33 fractions as a post-op or salvage XRT were considered.ResultsThe mean and maximal doses, dose inhomogeneities and conformity indexes for the planning target volumes were evaluated for each prescription cohort of patients. Similarly, the doses to OAR such as rectum, bladder and femoral heads were also assessed for various dose levels.ConclusionThis study shows that highly conformal radiation dose distribution for the treatment of prostate cancer is achievable with the VMAT technique. It provides evidence to support the adoption of such conformal technology in many disease sites such as the prostate. We believe that our experience reported here could help form the foundation for individual institutions to evaluate and develop the most suitable planning criteria tailored to their own needs and priority. This endeavour hopefully will provide further improvement in the planning process and, therefore, help achieve an effective and efficient delivery of radiotherapy for prostate cancer.

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