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22 State of the art and breast cancer treatments in Tomotherapy
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Abstracts / Physica Medica 56 (2018) 40–58
volume (PTV). Concerning the organs at risk we compared the values of the usual dosimetric parameters used to validate a plan treatment. The volumes of the 5, 10 and 15 Gy isodose lines were compared to investigate the low doses delivered to the body by the two irradiation plans. Results. The Paddick conformity index for the PTV is 52% greater for VMAT (0.87) than the 3DCRT (0.57) (p < 0.001). The homogeneity of dose is better by 39% in VMAT than in 3DCRT, the homogeneity index being respectively 0.07 and 0.11 (p < 0.001). For the spinal cord PRV, the average maximum dose is 45.6 Gy in 3DCRT against 19.3 Gy in VMAT (p < 0.001). Heart volume receiving at least 35 Gy (V35) decreased from 15.6% in 3DCRT to 8.28% in VMAT (p < 0.001). Esophageal V50 is also higher in 3DCRT than in VMAT, increasing from 14.03 to 25.45% (p = 0.002). The mean lung dose is 17.9 Gy in 3DCRT versus 15.5 Gy in VMAT, a decrease of 13% (p = 0.041); the V30 value is 23.6% in 3DCRT and 18.8% in VMAT, an improvement of 20% (p = 0.001). Nevertheless, there is no significant decrease in the V20 value, from 29% in 3DCRT to 24.84% in VMAT (p = 0.105). With regard to the low doses, it is found that the volumes receiving 5, 10 and 15 Gy, are not significantly different between the two irradiation techniques when the VMAT dosimetry is performed with partial arcs (p> 0.09). On the other hand, the volume receiving 5 Gy is significantly higher by 50% (p = 0.024) in VMAT compared to the 3DCRT for full arcs set up. Conclusions. The conformity and homogeneity indices at the target volume are improved in VMAT compared to the 3DCRT. The doses received by the organs at risk are significantly reduced, in particular the maximum dose to the spinal cord PRV and the V35 value for the heart, excepting the V20 value in lung which is not significantly smaller although it is an essential parameter in a lung plan evaluation. All these benefits are possible without increasing low doses when using a two partial arcs planning strategy. https://doi.org/10.1016/j.ejmp.2018.09.103
22 State of the art and breast cancer treatments in Tomotherapy M. Nirrengarten, N. Nomikossof, E. Garnier, D. Cowen AP-HM/Marseille, France Introduction. The most common female cancer is breast cancer. Classically performed in 3D conformational technique (RC3D) on a linear accelerator, it can also be performed on other machines such as Tomotherapy, mainly in case of treatment of both breasts or funnel breast. To use this treatment method for more indications of breast cancer requires a comparative study of ballistics from a linear accelerator with those of Tomotherapy. Methods. The treatment delivery on Tomotherapy can be performed helically (”TomoHelical”) or using fixed beams (”TomoDirect 3DCRT” and ”TomoDirect IMRT”). A state of the art of the methods used supported by a comparative dosimetric study will enable us to associate a privileged treatment technique for each indication. Results. At the time of writing this summary, the first results follow the publications: for breasts with or without tumor bed, TDIMRT enable to cover the PTV with a better conformation and save better the organs at risk compared to the conventional technique. Nevertheless, it causes a higher inhomogeneity (hot spots) in the target volume. For complete breasts (with nodes and internal breast chain), double breasts and chest walls, the helical technique reduces the pulmonary and/ or cardiac dose. Conclusions. The ballistics performed in Tomotherapy have proven to be mostly equivalent or better than those made in 3D. TD-IMRT appears to be a great technique for the treatment of a breast cancer
with or without a tumor bed. The helical technique is adapted for the treatment of complete breasts and chest walls. https://doi.org/10.1016/j.ejmp.2018.09.104
23 Vulvar cancer: Comparative study of novel 3D radiation therapy technique ‘‘ Advanced conformal technique ” and AP-PA irradiation techniques A. Nourreddine a,b, E. Marnouche a, M. A Krabch b, R.C. El moursli b, N. Benjaafar a a
Department of radiotherapy, National Institute of Oncology, Rabat, Morocco b Department of Physics, Faculty of Science, Mohammed V University, Rabat, Morocco Introduction. The commonly used technique of vulvar cancer radiation therapy consists of antero-posterior ‘‘AP” and postero-anterior ‘‘PA” fields. This is the first study that reports dosimetric comparison between the AP-PA techniques and the new 3D radiation therapy technique ‘‘advanced conformal technique ACT” based on the multiplicity of treatment fields in patients with squamous cell cancer of the vulva in post-operative setting. Methods. This is a comparative planning study of fifteen patients with vulvar carcinoma treated with adjuvant radiation therapy at the National Institute of Oncology in Rabat. Three treatment plans were performed, corresponding to three techniques; photons with source skin distance inguinal supplement, modified segmental boost technique, advanced conformal technique. For each plan, the dosevolume histogram was used to generate target volumes (total and inguinal PTV) and organs at risk OAR (bladder, rectum, bowel and femoral heads) parameters. Results. The isodose 95% volume was significantly reduced with the advanced conformal technique (p<0.0001) without compromising the total PTV coverage (p: 0.94). This technique resulted in the best conformity and homogeneity index. The ACT decreased significantly the PTVs Dmax and Dmean (p<0.0001), and offered better homogeneity for inguinal PTV 1.070.01 respectively (p<0.0001). The ACT decreased the rectum absorbed dose; V40, V45 and Dmax with 50.2127.21 22.8110.22 and 46.561.11 respectively. Concerning femoral heads, the ACT decreased the Dmax and V45 in comparison to the both other techniques. Conclusions. The ACT seems to be an alternative to the AP-PA irradiation techniques in post-operative setting when IMRT is not available. https://doi.org/10.1016/j.ejmp.2018.09.105
24 State of the art for breast cancer treatment in radiotherapy. Comparison of mono/multi isocentric conformational and helical techniques A. Leroux, I. Gabelle-Flandin, R. Sihanath, P. Chartier, F. Meneu, J.Y. Giraud CHU Grenoble Alpes, Grenoble, France Introduction. Breast cancers treatment are various in radiotherapy due to plenty combinations between tumor volumes to irradiate. This retrospective study aims to allow the best selection strategy according to tumor volumes location. A comparison between four dosimetric planification corresponding to helical [1] and direct tomotherapy and mono [2] and multi isocentric is realized on two treatment devices: Tomotherapy and conventional.
Abstracts / Physica Medica 56 (2018) 40–58
volume (PTV). Concerning the organs at risk we compared the values of the usual dosimetric parameters used to validate a plan treatment. The volumes of the 5, 10 and 15 Gy isodose lines were compared to investigate the low doses delivered to the body by the two irradiation plans. Results. The Paddick conformity index for the PTV is 52% greater for VMAT (0.87) than the 3DCRT (0.57) (p < 0.001). The homogeneity of dose is better by 39% in VMAT than in 3DCRT, the homogeneity index being respectively 0.07 and 0.11 (p < 0.001). For the spinal cord PRV, the average maximum dose is 45.6 Gy in 3DCRT against 19.3 Gy in VMAT (p < 0.001). Heart volume receiving at least 35 Gy (V35) decreased from 15.6% in 3DCRT to 8.28% in VMAT (p < 0.001). Esophageal V50 is also higher in 3DCRT than in VMAT, increasing from 14.03 to 25.45% (p = 0.002). The mean lung dose is 17.9 Gy in 3DCRT versus 15.5 Gy in VMAT, a decrease of 13% (p = 0.041); the V30 value is 23.6% in 3DCRT and 18.8% in VMAT, an improvement of 20% (p = 0.001). Nevertheless, there is no significant decrease in the V20 value, from 29% in 3DCRT to 24.84% in VMAT (p = 0.105). With regard to the low doses, it is found that the volumes receiving 5, 10 and 15 Gy, are not significantly different between the two irradiation techniques when the VMAT dosimetry is performed with partial arcs (p> 0.09). On the other hand, the volume receiving 5 Gy is significantly higher by 50% (p = 0.024) in VMAT compared to the 3DCRT for full arcs set up. Conclusions. The conformity and homogeneity indices at the target volume are improved in VMAT compared to the 3DCRT. The doses received by the organs at risk are significantly reduced, in particular the maximum dose to the spinal cord PRV and the V35 value for the heart, excepting the V20 value in lung which is not significantly smaller although it is an essential parameter in a lung plan evaluation. All these benefits are possible without increasing low doses when using a two partial arcs planning strategy. https://doi.org/10.1016/j.ejmp.2018.09.103
22 State of the art and breast cancer treatments in Tomotherapy M. Nirrengarten, N. Nomikossof, E. Garnier, D. Cowen AP-HM/Marseille, France Introduction. The most common female cancer is breast cancer. Classically performed in 3D conformational technique (RC3D) on a linear accelerator, it can also be performed on other machines such as Tomotherapy, mainly in case of treatment of both breasts or funnel breast. To use this treatment method for more indications of breast cancer requires a comparative study of ballistics from a linear accelerator with those of Tomotherapy. Methods. The treatment delivery on Tomotherapy can be performed helically (”TomoHelical”) or using fixed beams (”TomoDirect 3DCRT” and ”TomoDirect IMRT”). A state of the art of the methods used supported by a comparative dosimetric study will enable us to associate a privileged treatment technique for each indication. Results. At the time of writing this summary, the first results follow the publications: for breasts with or without tumor bed, TDIMRT enable to cover the PTV with a better conformation and save better the organs at risk compared to the conventional technique. Nevertheless, it causes a higher inhomogeneity (hot spots) in the target volume. For complete breasts (with nodes and internal breast chain), double breasts and chest walls, the helical technique reduces the pulmonary and/ or cardiac dose. Conclusions. The ballistics performed in Tomotherapy have proven to be mostly equivalent or better than those made in 3D. TD-IMRT appears to be a great technique for the treatment of a breast cancer
with or without a tumor bed. The helical technique is adapted for the treatment of complete breasts and chest walls. https://doi.org/10.1016/j.ejmp.2018.09.104
23 Vulvar cancer: Comparative study of novel 3D radiation therapy technique ‘‘ Advanced conformal technique ” and AP-PA irradiation techniques A. Nourreddine a,b, E. Marnouche a, M. A Krabch b, R.C. El moursli b, N. Benjaafar a a
Department of radiotherapy, National Institute of Oncology, Rabat, Morocco b Department of Physics, Faculty of Science, Mohammed V University, Rabat, Morocco Introduction. The commonly used technique of vulvar cancer radiation therapy consists of antero-posterior ‘‘AP” and postero-anterior ‘‘PA” fields. This is the first study that reports dosimetric comparison between the AP-PA techniques and the new 3D radiation therapy technique ‘‘advanced conformal technique ACT” based on the multiplicity of treatment fields in patients with squamous cell cancer of the vulva in post-operative setting. Methods. This is a comparative planning study of fifteen patients with vulvar carcinoma treated with adjuvant radiation therapy at the National Institute of Oncology in Rabat. Three treatment plans were performed, corresponding to three techniques; photons with source skin distance inguinal supplement, modified segmental boost technique, advanced conformal technique. For each plan, the dosevolume histogram was used to generate target volumes (total and inguinal PTV) and organs at risk OAR (bladder, rectum, bowel and femoral heads) parameters. Results. The isodose 95% volume was significantly reduced with the advanced conformal technique (p<0.0001) without compromising the total PTV coverage (p: 0.94). This technique resulted in the best conformity and homogeneity index. The ACT decreased significantly the PTVs Dmax and Dmean (p<0.0001), and offered better homogeneity for inguinal PTV 1.070.01 respectively (p<0.0001). The ACT decreased the rectum absorbed dose; V40, V45 and Dmax with 50.2127.21 22.8110.22 and 46.561.11 respectively. Concerning femoral heads, the ACT decreased the Dmax and V45 in comparison to the both other techniques. Conclusions. The ACT seems to be an alternative to the AP-PA irradiation techniques in post-operative setting when IMRT is not available. https://doi.org/10.1016/j.ejmp.2018.09.105
24 State of the art for breast cancer treatment in radiotherapy. Comparison of mono/multi isocentric conformational and helical techniques A. Leroux, I. Gabelle-Flandin, R. Sihanath, P. Chartier, F. Meneu, J.Y. Giraud CHU Grenoble Alpes, Grenoble, France Introduction. Breast cancers treatment are various in radiotherapy due to plenty combinations between tumor volumes to irradiate. This retrospective study aims to allow the best selection strategy according to tumor volumes location. A comparison between four dosimetric planification corresponding to helical [1] and direct tomotherapy and mono [2] and multi isocentric is realized on two treatment devices: Tomotherapy and conventional.