Introduction: Field-in-Field (FIF) and Intensity Modulated Radiation Therapy (IMRT) are two advanced radiation therapy planning techniques. Both of them are being used to achieve the same two related aims which are, t...Introduction: Field-in-Field (FIF) and Intensity Modulated Radiation Therapy (IMRT) are two advanced radiation therapy planning techniques. Both of them are being used to achieve the same two related aims which are, to expose the targeted tumor to the full radiation dose and to spare the nearby normal tissues (or organs) from being exposed to high amounts of radiation more than its tolerance dose limits. FIF is a forward planning while IMRT is an inverse planning and FIF is a forward IMRT. Aim: The purpose of this study was to compare between Field-in-Field and IMRT techniques in prostate cancer radiotherapy. Method: A treatment planning system supporting both inverse and forward planning facilities is used. Ten prostate cancer patients were planned with both FIF and IMRT planning techniques. Doses received by the Planning Target Volume (PTV) and Organs at Risk (OARs) were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that the IMRT planning technique achieved better dose coverage to the PTV than the FIF planning technique but, except RT and LT Femoral Heads, FIF achieved a better protection to the Rectum and the Bladder (OARs) than IMRT. Conclusions: The results showed that the inverse planning based IMRT technique is better and recommended in the prostate cancer radiotherapy than the FIF technique.展开更多
Introduction: Intensity Modulated Radiation Therapy (IMRT) planning dose calculation process depends on IMRT dose constraints. So, if there was any structure along the treatment beam path not delineated, it would not ...Introduction: Intensity Modulated Radiation Therapy (IMRT) planning dose calculation process depends on IMRT dose constraints. So, if there was any structure along the treatment beam path not delineated, it would not be taken into account during that calculation process. During IMRT routine practical work, it is noticed that there are some non-delineated normal tissue volumes that received un-aimed dose. Aim: The purpose of this study was to study the effect of unusually delineated normal volumes in IMRT treatment for left sided breast cancer. Method: Ten left sided breast cancer patients were planned with IMRT inverse planning system. The unusually delineated normal volumes were delineated and taken into account in IMRT dose constraints as an Organ at Risk. Doses received by that volume were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that doses received by the unusually delineated volume when they were delineated and taken into account in IMRT dose constraints were significantly higher than when they were not. Conclusions: The results showed that for IMRT planning technique used for treating left-sided breast cancer, all of the normal tissues/structures that are closed to the treatment targets must be delineated and taken into account in the IMRT planning dose constraints.展开更多
文摘Introduction: Field-in-Field (FIF) and Intensity Modulated Radiation Therapy (IMRT) are two advanced radiation therapy planning techniques. Both of them are being used to achieve the same two related aims which are, to expose the targeted tumor to the full radiation dose and to spare the nearby normal tissues (or organs) from being exposed to high amounts of radiation more than its tolerance dose limits. FIF is a forward planning while IMRT is an inverse planning and FIF is a forward IMRT. Aim: The purpose of this study was to compare between Field-in-Field and IMRT techniques in prostate cancer radiotherapy. Method: A treatment planning system supporting both inverse and forward planning facilities is used. Ten prostate cancer patients were planned with both FIF and IMRT planning techniques. Doses received by the Planning Target Volume (PTV) and Organs at Risk (OARs) were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that the IMRT planning technique achieved better dose coverage to the PTV than the FIF planning technique but, except RT and LT Femoral Heads, FIF achieved a better protection to the Rectum and the Bladder (OARs) than IMRT. Conclusions: The results showed that the inverse planning based IMRT technique is better and recommended in the prostate cancer radiotherapy than the FIF technique.
文摘Introduction: Intensity Modulated Radiation Therapy (IMRT) planning dose calculation process depends on IMRT dose constraints. So, if there was any structure along the treatment beam path not delineated, it would not be taken into account during that calculation process. During IMRT routine practical work, it is noticed that there are some non-delineated normal tissue volumes that received un-aimed dose. Aim: The purpose of this study was to study the effect of unusually delineated normal volumes in IMRT treatment for left sided breast cancer. Method: Ten left sided breast cancer patients were planned with IMRT inverse planning system. The unusually delineated normal volumes were delineated and taken into account in IMRT dose constraints as an Organ at Risk. Doses received by that volume were compared in the two methods quantitatively from Dose Volume Histograms (DVHs) and qualitatively from (axial cuts). Results: The results showed that doses received by the unusually delineated volume when they were delineated and taken into account in IMRT dose constraints were significantly higher than when they were not. Conclusions: The results showed that for IMRT planning technique used for treating left-sided breast cancer, all of the normal tissues/structures that are closed to the treatment targets must be delineated and taken into account in the IMRT planning dose constraints.
