Purpose: To investigate if intensity modulated radiation therapy (IMRT) offers a better planning target volume (PTV) coverage and/or lower dose to normal thoracic structures in comparison to three dimensional conforma...Purpose: To investigate if intensity modulated radiation therapy (IMRT) offers a better planning target volume (PTV) coverage and/or lower dose to normal thoracic structures in comparison to three dimensional conformal radiation therapy (3DCRT) in the treatment of mid and lower oesophageal carcinoma patients. Materials and Methods: A prospective study in the period from 2014 till 2015 was held in the radiation therapy department of the National Cancer Institute, Cairo University, in which 20 locally advanced or inoperable mid and lower oesophageal cancer patients were treated by chemo-radiation using 3DCRT technique. IMRT plans were generated for those 20 patients. The 3DCRT and IMRT plans were compared as regards PTV coverage and doses to critical organs at risk. Results: All plans had produced satisfactory PTV coverage with no significant differences noted. The lung V20 for both lungs in 3DCRT was 16.94% ± 4.2% which was increased to 21.42% ± 3.6% in IMRT (p = 0.017). The mean dose to the heart and V30 were higher in IMRT plans while the mean dose to the spinal cord was higher with 3DCRT plans, yet that didn’t reach a statistically significant level (p = 0.156). The dose delivered to the liver didn’t pose any difference between both techniques. Conclusion: 3DCRT remains to be a feasible cost effective treatment delivery option for mid and lower oesophageal cancer cases with a lower optimization and delivery time than that for IMRT. Moreover, that calls for further dosimetric studies and clinical trials to assess IMRT technique. In our study, IMRT using nine fields didn’t prove to be superior to 3DCRT.展开更多
Background: Conventional tomotherapy platforms only allow for the delivery of helical IMRT. However the use of IMRT and helical delivery in breast cancer treatment is non-standard. Newer tomotherapy units are equipped...Background: Conventional tomotherapy platforms only allow for the delivery of helical IMRT. However the use of IMRT and helical delivery in breast cancer treatment is non-standard. Newer tomotherapy units are equipped with a static-beam mode with 3DCRT capabilities. During the clinical use, we frequently observe hot-spots in the plan that renders the plan clinically unacceptable. The purpose of this study is to investigate the underlying cause of the hot-spots in tomotherapy static-beam breast treatment and possible solutions. Materials/Methods: Theories about the formation of the hot-spot were developed. Eight lumpectomy patients contoured according to RTOG-1005 specifications were also used to illustrate the magnitude of hot-spots under various planning strategies. Two tangential beams were used for the whole breast irradiation plan with prescription dose of 40 Gy in 15 fractions. Results: The hot-spot was identified as the behavior of the optimization engine when part of the target region was blocked. With the current design of tomotherapy’s 3DCRT planning where user adjustment was greatly limited, none of the planning strategies were able to reduce the hot-spots to acceptable levels in the eight patients studied. The best strategy still produced an average of 48.5 Gy (121% of prescription dose) hot-spot dose and 30.4 cc hot-spot volume (volume receiving > 110% prescription dose). It is also shown that the hot-spot was not a result of energy or other physical limitation of the radiation device. By manually adjusting the plan sinogram, the maximum hot-spot dose drops from 121% to 111% and the hot-spot volume drops from 30 cc to 6 cc on average. Conclusions: While TomoDirect 3DCRT showed great promise in breast treatment, treatment planning software improvements may be needed in order to improve the clinical acceptability by reducing hot-spots in normal tissue.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 distribution in 1) different breast volume categories, 2) nodal irradiation versus breast only, and 3) boost versus no boost. Results</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;">The</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> routinely reported dose </span><span style="font-family:Verdana;">constrains</span><span style="font-family:Verdana;"> for the ipsilateral lung and </span><span style="font-family:Verdana;">for</span><span style="font-family:Verdana;"> the heart were not significantly different on comparing the three techniques. While for the contralateral lung, the difference in mean dose was in favor of 3DCRT.</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">In large breast </span><span style="font-family:Verdana;">volume,</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">3DCRT provided a lower Max dose to the contralateral </span><span style="font-family:Verdana;">lung</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;">and</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the</span></span></span><span><span><span style="font-family:""> <span style="font-family:Verdana;">lowest</span><span style="font-family:Verdana;"> mean dose to the contralateral breast when compared to IMRT p < 0. 046</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;">In</span></span></span><span><span><span style="font-family:""> <span style="font-family:Verdana;">case</span><span style="font-family:Verdana;"> of no nodal irradiation, the contralateral breast </span><span style="font-family:Verdana;">mean</span><span style="font-family:Verdana;"> dose was lower in 3DCRT in comparison to IMRT and VMAT p < 0.037. When boost dose was given, 3DCRT plans had produced a lower Max dose to the contralateral lung p < 0.017. Conclusion</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;">The</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> three techniques (3DCRT, IMRT, and VMAT) can meet the clinical dosimetry demands of radiotherapy for left breast cancer after conservative surgery, as long as the routinely OARs only (heart and ipsilateral lung) </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> reported. Our study showed that 3CDRT can provide a lower dose to the contralateral organs (breast and lung), </span><span style="font-family:Verdana;">specially</span><span style="font-family:Verdana;">, in case of large breast volumes, no nodal irradiation </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> when a boost </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">given</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.展开更多
目的探讨利用3D C R T技术治疗颅外肿瘤时大幅度提高分次量的可能性。方法回顾性分析总结300例颅外肿瘤的治疗计划。其中胸部肿瘤143例,腹部肿瘤157例。计划靶区体积7.0 ̄1478cm3,多数计划以90%的等剂量线包围PTV,少数以80%的等剂量线包...目的探讨利用3D C R T技术治疗颅外肿瘤时大幅度提高分次量的可能性。方法回顾性分析总结300例颅外肿瘤的治疗计划。其中胸部肿瘤143例,腹部肿瘤157例。计划靶区体积7.0 ̄1478cm3,多数计划以90%的等剂量线包围PTV,少数以80%的等剂量线包围PTV的95%。以参考点剂量的90%为处方剂量,分次剂量多为5 ̄10G y,众数剂量为6 ̄8G y,疗程一般为5 ̄15d,间隔0 ̄1d,总剂量视情况给到常规治疗的根治量或姑息量,生物效应则增加10% ̄40%。结果所有治疗计划均顺利完成,患者未出现影响生存质量的并发症。结论由于f因子的作用,3D C R T使得较大幅度增加分次量,缩短总疗程,提高放射的生物效应成为可能;对于体积较大的肿瘤在治疗开始时应积极考虑使用3D C R T技术;由于认知水平有限,使用3D C R T技术不宜过分追求精确计划、精确设计、精确治疗;使用3D C R T技术治疗颅外肿瘤时视治疗目的的不同,给予常规放疗2 ̄3倍的分次量是安全、可靠、有效的。展开更多
文摘Purpose: To investigate if intensity modulated radiation therapy (IMRT) offers a better planning target volume (PTV) coverage and/or lower dose to normal thoracic structures in comparison to three dimensional conformal radiation therapy (3DCRT) in the treatment of mid and lower oesophageal carcinoma patients. Materials and Methods: A prospective study in the period from 2014 till 2015 was held in the radiation therapy department of the National Cancer Institute, Cairo University, in which 20 locally advanced or inoperable mid and lower oesophageal cancer patients were treated by chemo-radiation using 3DCRT technique. IMRT plans were generated for those 20 patients. The 3DCRT and IMRT plans were compared as regards PTV coverage and doses to critical organs at risk. Results: All plans had produced satisfactory PTV coverage with no significant differences noted. The lung V20 for both lungs in 3DCRT was 16.94% ± 4.2% which was increased to 21.42% ± 3.6% in IMRT (p = 0.017). The mean dose to the heart and V30 were higher in IMRT plans while the mean dose to the spinal cord was higher with 3DCRT plans, yet that didn’t reach a statistically significant level (p = 0.156). The dose delivered to the liver didn’t pose any difference between both techniques. Conclusion: 3DCRT remains to be a feasible cost effective treatment delivery option for mid and lower oesophageal cancer cases with a lower optimization and delivery time than that for IMRT. Moreover, that calls for further dosimetric studies and clinical trials to assess IMRT technique. In our study, IMRT using nine fields didn’t prove to be superior to 3DCRT.
文摘Background: Conventional tomotherapy platforms only allow for the delivery of helical IMRT. However the use of IMRT and helical delivery in breast cancer treatment is non-standard. Newer tomotherapy units are equipped with a static-beam mode with 3DCRT capabilities. During the clinical use, we frequently observe hot-spots in the plan that renders the plan clinically unacceptable. The purpose of this study is to investigate the underlying cause of the hot-spots in tomotherapy static-beam breast treatment and possible solutions. Materials/Methods: Theories about the formation of the hot-spot were developed. Eight lumpectomy patients contoured according to RTOG-1005 specifications were also used to illustrate the magnitude of hot-spots under various planning strategies. Two tangential beams were used for the whole breast irradiation plan with prescription dose of 40 Gy in 15 fractions. Results: The hot-spot was identified as the behavior of the optimization engine when part of the target region was blocked. With the current design of tomotherapy’s 3DCRT planning where user adjustment was greatly limited, none of the planning strategies were able to reduce the hot-spots to acceptable levels in the eight patients studied. The best strategy still produced an average of 48.5 Gy (121% of prescription dose) hot-spot dose and 30.4 cc hot-spot volume (volume receiving > 110% prescription dose). It is also shown that the hot-spot was not a result of energy or other physical limitation of the radiation device. By manually adjusting the plan sinogram, the maximum hot-spot dose drops from 121% to 111% and the hot-spot volume drops from 30 cc to 6 cc on average. Conclusions: While TomoDirect 3DCRT showed great promise in breast treatment, treatment planning software improvements may be needed in order to improve the clinical acceptability by reducing hot-spots in normal tissue.
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 distribution in 1) different breast volume categories, 2) nodal irradiation versus breast only, and 3) boost versus no boost. Results</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;">The</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> routinely reported dose </span><span style="font-family:Verdana;">constrains</span><span style="font-family:Verdana;"> for the ipsilateral lung and </span><span style="font-family:Verdana;">for</span><span style="font-family:Verdana;"> the heart were not significantly different on comparing the three techniques. While for the contralateral lung, the difference in mean dose was in favor of 3DCRT.</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">In large breast </span><span style="font-family:Verdana;">volume,</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">3DCRT provided a lower Max dose to the contralateral </span><span style="font-family:Verdana;">lung</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;">and</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the</span></span></span><span><span><span style="font-family:""> <span style="font-family:Verdana;">lowest</span><span style="font-family:Verdana;"> mean dose to the contralateral breast when compared to IMRT p < 0. 046</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;">In</span></span></span><span><span><span style="font-family:""> <span style="font-family:Verdana;">case</span><span style="font-family:Verdana;"> of no nodal irradiation, the contralateral breast </span><span style="font-family:Verdana;">mean</span><span style="font-family:Verdana;"> dose was lower in 3DCRT in comparison to IMRT and VMAT p < 0.037. When boost dose was given, 3DCRT plans had produced a lower Max dose to the contralateral lung p < 0.017. Conclusion</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;">The</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> three techniques (3DCRT, IMRT, and VMAT) can meet the clinical dosimetry demands of radiotherapy for left breast cancer after conservative surgery, as long as the routinely OARs only (heart and ipsilateral lung) </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> reported. Our study showed that 3CDRT can provide a lower dose to the contralateral organs (breast and lung), </span><span style="font-family:Verdana;">specially</span><span style="font-family:Verdana;">, in case of large breast volumes, no nodal irradiation </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> when a boost </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">given</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.
文摘目的探讨利用3D C R T技术治疗颅外肿瘤时大幅度提高分次量的可能性。方法回顾性分析总结300例颅外肿瘤的治疗计划。其中胸部肿瘤143例,腹部肿瘤157例。计划靶区体积7.0 ̄1478cm3,多数计划以90%的等剂量线包围PTV,少数以80%的等剂量线包围PTV的95%。以参考点剂量的90%为处方剂量,分次剂量多为5 ̄10G y,众数剂量为6 ̄8G y,疗程一般为5 ̄15d,间隔0 ̄1d,总剂量视情况给到常规治疗的根治量或姑息量,生物效应则增加10% ̄40%。结果所有治疗计划均顺利完成,患者未出现影响生存质量的并发症。结论由于f因子的作用,3D C R T使得较大幅度增加分次量,缩短总疗程,提高放射的生物效应成为可能;对于体积较大的肿瘤在治疗开始时应积极考虑使用3D C R T技术;由于认知水平有限,使用3D C R T技术不宜过分追求精确计划、精确设计、精确治疗;使用3D C R T技术治疗颅外肿瘤时视治疗目的的不同,给予常规放疗2 ̄3倍的分次量是安全、可靠、有效的。