Objective： The work is a comparative study between two modalities of radiation therapy, the aim of which is to compare 3D conformal radiation therapy （3D-CRT） and intensity modulated radiation therapy （IMRT） in t...Objective： The work is a comparative study between two modalities of radiation therapy, the aim of which is to compare 3D conformal radiation therapy （3D-CRT） and intensity modulated radiation therapy （IMRT） in treating posterior fossa boost in children with high risk medulloblastorna; dosimetrically evaluating and comparing both techniques as regard target coverage and doses to organs at risk （OAR）. Methods： Twenty patients with high risk medulloblastoma were treated by 3D-CRT technique. A dosimetric comparison was done by performing two plans for the posterior fossa boost, 3D-CRT and IMRT plans, for the same patient using Eclipse planning system （version 8.6）. Results： IMRT had a better conformity index compared to 3D-CRT plans （P value of 0.000）. As for the dose homogeneity it was also better in the IMRT plans, yet it hasn＇t reached the statistical significant value. Also, doses received by the cochleae, brainstem and spinal cord were significantly less in the IMRT plans than those of 3D-CRT （P value 〈 0.05）. Conclusion： IMRT technique was clearly able to improve conformity and homogeneity index, spare the cochleae, reduce dose to the brainstem and spinal cord in comparison to 3D- CRT technique.展开更多
Objective： To observe the effects of the new technique of flexible 3D-conformal radiotherapy with combination of photon and electron （3DCRT） in the treatment of the patients with diffuse malignant pleural mesotheli...Objective： To observe the effects of the new technique of flexible 3D-conformal radiotherapy with combination of photon and electron （3DCRT） in the treatment of the patients with diffuse malignant pleural mesothelioma （MPM）, and carry out the comparative study between flexible 3DCRT and hemithoracic conventional radiotherapy （CRT）. Methods： From January 2004 to October 2007, 8 patients with MPM were treated with flexible 3DCRT. 5 patients had received cycles of chemotherapy before radiation. New technique of flexible 3DCRT with combination of photon and electron was used in our study, and DT 32.2-64 Gy with conventional split were delivered. CRT technique was mimicked to compare with 3DCRT technique to predict the possibility of lung damage in two methods. Results： One patient reached CR and other 7 patients got PR after radiation. Two patients died during the follow-up. The median survival time （MST） was 15.4 months and it was 18.8 months for sequential chemotherapy and radiotherapy group and 9.7 months for radiotherapy alone group. The V20, V30, and ipsilateral and contralateral median lung dosage （MLD） were 20.5%, 15.6%, 18.8 Gy and 2.2 Gy respectively when the flexible 3DCRT technique was used, whereas they were 36.8%, 27.9%, 31.1 Gy and 1.2 Gy respectively when the CRT technique was used. They were statistically different for the lung V20, V30 and ipsilateral MLD between the two techniques （P 〈 0.01）, whereas there was no different for the contralateral MLD （P = 0.08）. All patients received radiation were found to have lung fibrosis and classified as grades 1-2 radiation pneumonitis. The quality of life was increased from score 2.83 to 3.76 and it was significantly different （P 〈 0.01）. Conclusion： MPM is moderately sensitive to radiation. The flexible 3DCRT technique is feasible in the treatment of MPM and lung damage is reduced apparently comparing with the CRT technique. The quality of life of patients with MPM is improved after irradiation.展开更多
Introduction: Radiation therapy after breast surgery is an integral part of the treatment of early breast cancer. The goal of radiation therapy is to achieve the best possible coverage of the planning target volume (P...Introduction: Radiation therapy after breast surgery is an integral part of the treatment of early breast cancer. The goal of radiation therapy is to achieve the best possible coverage of the planning target volume (PTV), while reducing the dose to organs at risk (OARs) which are normal tissues whose sensitivity to irradiation could cause damage that can lead to modification of the treatment plan. In the last decade, radiation oncologist started to use the Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) for irradiating the breast, in order to achieve better dose distribution and target dose to the PTV and OAR. The aim of this study is to compare 2 external radiotherapy techniques (VMAT vs 3D) for patients with node-positive left breast cancer. Patients and Methods: We randomly selected 10 cases of postoperative radiotherapy for breast cancer in our hospital. The patients are all female, the average age was 45.4 years old, and the primary lesions are left breast. The ANOVA test was used to compare the mean difference between subgroups, and the p value Results: Dose volume histogram (DVH) was used to analyze each evaluation dose of clinical target volume (CTV) and organs at risk (OARs). Compared to 3DCRT plans, VMAT provided more uniform coverage to the breast and regional lymph nodes. The max point dose for tVMAT was lower on average (106.4% for VMAT versus 109% for 3DCRT). OAR sparing was improved with tVMAT, with a lower average V17Gy for the left lung (27.91% for VMAT versus 30.04% for 3DCRT, p and lower for V28Gy (13.75% for VMAT versus 22.34% for 3DCRT, p = 0.01). We also found a lower V35Gy for the heart on VMAT plan (p = 0.02). On the contrary, dose of contralateral breast was lower in 3DCRT than VMAT (0.59 Gy vs 3.65 Gy, p = 0.00). Conclusion: The both types of plans can meet the clinical dosimetry demands of postoperative radiotherapy for left breast cancer. The VMAT plan has a better conformity, but 3CDRT can provide a lower dose to the contralateral organs (breast and lung) to avoid the risk of secondary cancers.展开更多
Radiotherapy techniques have substantially improved in the last two decades. After the introduction of 3-dimensional conformal radiotherapy, radiotherapy has been increasingly used for the treatment of hepatocellular ...Radiotherapy techniques have substantially improved in the last two decades. After the introduction of 3-dimensional conformal radiotherapy, radiotherapy has been increasingly used for the treatment of hepatocellular carcinoma(HCC). Currently, more advanced techniques, including intensity-modulated radiotherapy(IMRT), stereotactic ablative body radiotherapy(SABR), and charged particle therapy, are used for the treatment of HCC. IMRT can escalate the tumor dose while sparing the normal tissue even though the tumor is large or located near critical organs. SABR can deliver a very high radiation dose to small HCCs in a few fractions, leading to high local control rates of 84%-100%. Various advanced imaging modalities are used for radiotherapy planning and delivery to improve the precision of radiotherapy. These advanced techniques enable the delivery of high dose radiotherapy for early to advanced HCCs without increasing the radiation-induced toxicities. However, as there have been no effective tools for the prediction of the response to radiotherapy or recurrences within or outside the radiation field, future studies should focus on selecting the patients who will benefit from radiotherapy.展开更多
文摘Objective： The work is a comparative study between two modalities of radiation therapy, the aim of which is to compare 3D conformal radiation therapy （3D-CRT） and intensity modulated radiation therapy （IMRT） in treating posterior fossa boost in children with high risk medulloblastorna; dosimetrically evaluating and comparing both techniques as regard target coverage and doses to organs at risk （OAR）. Methods： Twenty patients with high risk medulloblastoma were treated by 3D-CRT technique. A dosimetric comparison was done by performing two plans for the posterior fossa boost, 3D-CRT and IMRT plans, for the same patient using Eclipse planning system （version 8.6）. Results： IMRT had a better conformity index compared to 3D-CRT plans （P value of 0.000）. As for the dose homogeneity it was also better in the IMRT plans, yet it hasn＇t reached the statistical significant value. Also, doses received by the cochleae, brainstem and spinal cord were significantly less in the IMRT plans than those of 3D-CRT （P value 〈 0.05）. Conclusion： IMRT technique was clearly able to improve conformity and homogeneity index, spare the cochleae, reduce dose to the brainstem and spinal cord in comparison to 3D- CRT technique.
文摘Objective： To observe the effects of the new technique of flexible 3D-conformal radiotherapy with combination of photon and electron （3DCRT） in the treatment of the patients with diffuse malignant pleural mesothelioma （MPM）, and carry out the comparative study between flexible 3DCRT and hemithoracic conventional radiotherapy （CRT）. Methods： From January 2004 to October 2007, 8 patients with MPM were treated with flexible 3DCRT. 5 patients had received cycles of chemotherapy before radiation. New technique of flexible 3DCRT with combination of photon and electron was used in our study, and DT 32.2-64 Gy with conventional split were delivered. CRT technique was mimicked to compare with 3DCRT technique to predict the possibility of lung damage in two methods. Results： One patient reached CR and other 7 patients got PR after radiation. Two patients died during the follow-up. The median survival time （MST） was 15.4 months and it was 18.8 months for sequential chemotherapy and radiotherapy group and 9.7 months for radiotherapy alone group. The V20, V30, and ipsilateral and contralateral median lung dosage （MLD） were 20.5%, 15.6%, 18.8 Gy and 2.2 Gy respectively when the flexible 3DCRT technique was used, whereas they were 36.8%, 27.9%, 31.1 Gy and 1.2 Gy respectively when the CRT technique was used. They were statistically different for the lung V20, V30 and ipsilateral MLD between the two techniques （P 〈 0.01）, whereas there was no different for the contralateral MLD （P = 0.08）. All patients received radiation were found to have lung fibrosis and classified as grades 1-2 radiation pneumonitis. The quality of life was increased from score 2.83 to 3.76 and it was significantly different （P 〈 0.01）. Conclusion： MPM is moderately sensitive to radiation. The flexible 3DCRT technique is feasible in the treatment of MPM and lung damage is reduced apparently comparing with the CRT technique. The quality of life of patients with MPM is improved after irradiation.
文摘Introduction: Radiation therapy after breast surgery is an integral part of the treatment of early breast cancer. The goal of radiation therapy is to achieve the best possible coverage of the planning target volume (PTV), while reducing the dose to organs at risk (OARs) which are normal tissues whose sensitivity to irradiation could cause damage that can lead to modification of the treatment plan. In the last decade, radiation oncologist started to use the Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) for irradiating the breast, in order to achieve better dose distribution and target dose to the PTV and OAR. The aim of this study is to compare 2 external radiotherapy techniques (VMAT vs 3D) for patients with node-positive left breast cancer. Patients and Methods: We randomly selected 10 cases of postoperative radiotherapy for breast cancer in our hospital. The patients are all female, the average age was 45.4 years old, and the primary lesions are left breast. The ANOVA test was used to compare the mean difference between subgroups, and the p value Results: Dose volume histogram (DVH) was used to analyze each evaluation dose of clinical target volume (CTV) and organs at risk (OARs). Compared to 3DCRT plans, VMAT provided more uniform coverage to the breast and regional lymph nodes. The max point dose for tVMAT was lower on average (106.4% for VMAT versus 109% for 3DCRT). OAR sparing was improved with tVMAT, with a lower average V17Gy for the left lung (27.91% for VMAT versus 30.04% for 3DCRT, p and lower for V28Gy (13.75% for VMAT versus 22.34% for 3DCRT, p = 0.01). We also found a lower V35Gy for the heart on VMAT plan (p = 0.02). On the contrary, dose of contralateral breast was lower in 3DCRT than VMAT (0.59 Gy vs 3.65 Gy, p = 0.00). Conclusion: The both types of plans can meet the clinical dosimetry demands of postoperative radiotherapy for left breast cancer. The VMAT plan has a better conformity, but 3CDRT can provide a lower dose to the contralateral organs (breast and lung) to avoid the risk of secondary cancers.
文摘Radiotherapy techniques have substantially improved in the last two decades. After the introduction of 3-dimensional conformal radiotherapy, radiotherapy has been increasingly used for the treatment of hepatocellular carcinoma(HCC). Currently, more advanced techniques, including intensity-modulated radiotherapy(IMRT), stereotactic ablative body radiotherapy(SABR), and charged particle therapy, are used for the treatment of HCC. IMRT can escalate the tumor dose while sparing the normal tissue even though the tumor is large or located near critical organs. SABR can deliver a very high radiation dose to small HCCs in a few fractions, leading to high local control rates of 84%-100%. Various advanced imaging modalities are used for radiotherapy planning and delivery to improve the precision of radiotherapy. These advanced techniques enable the delivery of high dose radiotherapy for early to advanced HCCs without increasing the radiation-induced toxicities. However, as there have been no effective tools for the prediction of the response to radiotherapy or recurrences within or outside the radiation field, future studies should focus on selecting the patients who will benefit from radiotherapy.
