Background: The treatment of brain metastases with radiotherapy has shifted to the use of Stereotactic Radio-surgery (SRS). The technical issue of expanding the treatment volume around the Gross Tumor Volume (GTV) is ...Background: The treatment of brain metastases with radiotherapy has shifted to the use of Stereotactic Radio-surgery (SRS). The technical issue of expanding the treatment volume around the Gross Tumor Volume (GTV) is a current debate. Radiotherapy centers use variable GTV-PTV margins, ranging from one to 2 mm. Material and Methods: We performed a dosimetric comparison in plans of twenty patients using three margins: PTV zero, PTV1, and PTV2. We also developed imaginary Peel volumes. These volumes are described as follows: Peel1 = PTV1 − GTV, Peel2 = PTV2 − GTV. Results: Our results showed that the mean PTV volume differed significantly across the different margins (p = 0.000). The V12 of the brain significantly varied as a function of PTV margin (p = 0.000). The target coverage and plan quality indices were not significantly different. The Peel volume dosimetric analysis showed that the mean dose was significantly higher in the nearby normal brain tissue: Peel1 (p = 0.022) and Peel 2 (p = 0.013). Conclusion: According to our dosimetric analysis, expanding the GTV into a PTV by 1 mm margin is more convenient than 2 mm.展开更多
<strong>Background:</strong><span style="font-family:""><span style="font-family:Verdana;"> Breast cancer is the most common cancer diagnosed worldwide, synchronous bil...<strong>Background:</strong><span style="font-family:""><span style="font-family:Verdana;"> Breast cancer is the most common cancer diagnosed worldwide, synchronous bilateral breast cancer accounts for </span><span style="font-family:Verdana;">unique</span><span style="font-family:Verdana;"> entity of the disease, particularly post-operative radiotherapy for Synchronous Bilateral Breast Cancer (SBBC) is challenging with </span><span style="font-family:Verdana;">lack</span><span style="font-family:Verdana;"> of evidence about the best irradiation technique. In this </span><span style="font-family:Verdana;">study</span></span><span style="font-family:Verdana;">,</span><span style="font-family:""><span style="font-family:Verdana;"> we tried to explore the optimum radiotherapy technique regarding the dosimetric parameters. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> We recruited 15 SBBC patients in whom </span><span style="font-family:Verdana;">post-operative</span><span style="font-family:Verdana;"> radiotherapy was indicated and we established three plans for each patient using 3DCRT, IMRT </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> VMAT, and then we compared the three plans as regard target volume coverage parameters and organs at risk (OAR) doses. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> We found that PTV coverage parameter was superior with IMRT compared with 3DCRT and VMAT in terms of Dmean (p = 0.001), D95% (p = 0.001), D</span><sub><span style="font-family:Verdana;">max</span></sub><span style="font-family:Verdana;"> (p = 0.0001), conformity index (p = 0.0001) and HI (p = 0.0001). Doses to OAR w</span></span><span style="font-family:Verdana;">ere</span><span style="font-family:""><span style="font-family:Verdana;"> not significantly different between the three techniques in </span><span style="font-family:Verdana;">cardiac</span><span style="font-family展开更多
Radiation therapy after conservative breast surgery is an integral part of the treatment of early breast cancer</span><span style="font-family:Verdana;">.</span></span></span>&l...Radiation therapy after conservative breast surgery is an integral part of the treatment of early breast cancer</span><span style="font-family:Verdana;">.</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">The aim of radiotherapy is</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> to achieve the best coverage of </span><span style="font-family:Verdana;">the</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">Planning</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> Target Volume (PTV</span><span style="font-family:Verdana;">),</span><span style="font-family:Verdana;"> while reducing the dose to the Organs at Risk (OAR). Such goals are not always achievable with the conformal three dimensions plans (3DCRT). Recently, </span><span style="font-family:Verdana;">radiation</span><span style="font-family:Verdana;"> oncologist uses Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT)</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">for irradiating the breast. In this study, we compared 3DCRT, IMRT </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> VMAT for left breast cancer patients in terms of PTV coverage, OAR</span><span style="font-family:Verdana;">.</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">We</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> also revised the different dose di展开更多
文摘Background: The treatment of brain metastases with radiotherapy has shifted to the use of Stereotactic Radio-surgery (SRS). The technical issue of expanding the treatment volume around the Gross Tumor Volume (GTV) is a current debate. Radiotherapy centers use variable GTV-PTV margins, ranging from one to 2 mm. Material and Methods: We performed a dosimetric comparison in plans of twenty patients using three margins: PTV zero, PTV1, and PTV2. We also developed imaginary Peel volumes. These volumes are described as follows: Peel1 = PTV1 − GTV, Peel2 = PTV2 − GTV. Results: Our results showed that the mean PTV volume differed significantly across the different margins (p = 0.000). The V12 of the brain significantly varied as a function of PTV margin (p = 0.000). The target coverage and plan quality indices were not significantly different. The Peel volume dosimetric analysis showed that the mean dose was significantly higher in the nearby normal brain tissue: Peel1 (p = 0.022) and Peel 2 (p = 0.013). Conclusion: According to our dosimetric analysis, expanding the GTV into a PTV by 1 mm margin is more convenient than 2 mm.
文摘<strong>Background:</strong><span style="font-family:""><span style="font-family:Verdana;"> Breast cancer is the most common cancer diagnosed worldwide, synchronous bilateral breast cancer accounts for </span><span style="font-family:Verdana;">unique</span><span style="font-family:Verdana;"> entity of the disease, particularly post-operative radiotherapy for Synchronous Bilateral Breast Cancer (SBBC) is challenging with </span><span style="font-family:Verdana;">lack</span><span style="font-family:Verdana;"> of evidence about the best irradiation technique. In this </span><span style="font-family:Verdana;">study</span></span><span style="font-family:Verdana;">,</span><span style="font-family:""><span style="font-family:Verdana;"> we tried to explore the optimum radiotherapy technique regarding the dosimetric parameters. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> We recruited 15 SBBC patients in whom </span><span style="font-family:Verdana;">post-operative</span><span style="font-family:Verdana;"> radiotherapy was indicated and we established three plans for each patient using 3DCRT, IMRT </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> VMAT, and then we compared the three plans as regard target volume coverage parameters and organs at risk (OAR) doses. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> We found that PTV coverage parameter was superior with IMRT compared with 3DCRT and VMAT in terms of Dmean (p = 0.001), D95% (p = 0.001), D</span><sub><span style="font-family:Verdana;">max</span></sub><span style="font-family:Verdana;"> (p = 0.0001), conformity index (p = 0.0001) and HI (p = 0.0001). Doses to OAR w</span></span><span style="font-family:Verdana;">ere</span><span style="font-family:""><span style="font-family:Verdana;"> not significantly different between the three techniques in </span><span style="font-family:Verdana;">cardiac</span><span style="font-family
文摘Radiation therapy after conservative breast surgery is an integral part of the treatment of early breast cancer</span><span style="font-family:Verdana;">.</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">The aim of radiotherapy is</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> to achieve the best coverage of </span><span style="font-family:Verdana;">the</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">Planning</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> Target Volume (PTV</span><span style="font-family:Verdana;">),</span><span style="font-family:Verdana;"> while reducing the dose to the Organs at Risk (OAR). Such goals are not always achievable with the conformal three dimensions plans (3DCRT). Recently, </span><span style="font-family:Verdana;">radiation</span><span style="font-family:Verdana;"> oncologist uses Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT)</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">for irradiating the breast. In this study, we compared 3DCRT, IMRT </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> VMAT for left breast cancer patients in terms of PTV coverage, OAR</span><span style="font-family:Verdana;">.</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">We</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> also revised the different dose di
