Dosimetric comparison between three‑ and four‑dimensional computerised tomography radiotherapy for breast cancer

Abstract

At present, methods of radiotherapy simulation for breast cancer based on four-dimensional computerised tomography (4D-CT) or three-dimensional CT (3D-CT) simulation remain controversial. In the present study, 7 patients with residual breast tissue received whole breast radiotherapy based on 3D-CT and 4D-CT simulation. For the 4D-CT plan, four types of CT images were produced, including images of the end of inspiration and the end of expiration, and images acquired by the maximal intensity projection (MIP) and average intensity projection (AIP). In the 3D-CT plan, the clinical target volume (CTV) and plan target volume (PTV) were marginally higher compared with the 4D-CT plan. In addition, the minimum point dose of the target volume ( D min ), the maximum point dose of the target volume ( D max ) and the mean point dose of the target volume ( D mean ) of the CTV and PTV in the MIP and AIP plans were marginally higher compared with the 3D-CT plan. For the contralateral breast (C-B), volumes of the 4D-CT plan were markedly lower compared with the 3D-CT plan. Furthermore, D min , D max and D mean of the 3D-CT plan were higher compared with the AIP and MIP plans. For the ipsilateral lungs (I-L), volumes of the 3D-CT and AIP plans were higher compared with the MIP plan. Furthermore, when breast lesions were on the left side, for the heart, the volume receiving no less than 40% of the prescription dose ( V 40 ) and the volume receiving no less than 30% of the prescription dose ( V 30 ) of the MIP and AIP plans were slightly lower compared with those of the 3D plan. In conclusion, 4D-CT radiotherapy based on the MIP and AIP plans provides a slightly smaller radiation area and slightly higher radiotherapy dosage of the CTV and PTV compared with 3D-CT radiotherapy for breast radiotherapy. Therefore, the MIP and AIP plans prevent C-B radiation exposure and improve sparing of the heart and I-L.

A Comparison of 3D Conformal and Deep Inspiratory Breath Holding vs. 4D-CT Intensity-Modulated Radiation Therapy for Patients with Left Breast Cancer

“…As an alternative to FB-IMRT, 3D-DIBH offers patients with left-sided breast cancer a clinically equal course of treatment while protecting vulnerable organs and being more easily implemented. In our study, the dosimetry of some organs at risk in the 4D IMRT plans was significantly lower than the 3D conformal with DIBH plans, including the mean heart dose, which is in concordance with Yanli Yan's study [26]. Regarding 4D IMRT, our findings are contrast those found in Reardon and Hayden's study, in which the mean LAD dose showed no significant difference between both the 3D conformal with the DIBH plan and the 4D IMRT plan in relation to the DIBH arm in comparison with the FB arm, and the maximum LAD dose showed no significant difference between the 3D DIBH and 4D-CT IMRT plans [22,28].…”

“…Regarding 4D IMRT, our findings are contrast those found in Reardon and Hayden's study, in which the mean LAD dose showed no significant difference between both the 3D conformal with the DIBH plan and the 4D IMRT plan in relation to the DIBH arm in comparison with the FB arm, and the maximum LAD dose showed no significant difference between the 3D DIBH and 4D-CT IMRT plans [22,28]. With regard to V3 of the contralateral breast, it was significantly lower in the 3D conformal with the DIBH plan than in the 4D IMRT plan, which contrasts Yanli Yan et al's study [26] and supports the findings of Reardon and Hayden's study [28]. Moreover, the cervical esophagus was significantly higher in the 4D IMRT plan than in the 3D conformal plan, especially in patients with supraclavicular irradiation.…”

“…The 4D-CT method can produce more precise images of tumors and healthy organs than traditional scanning [19]. In Yanli Yan's study [26], seven patients with remaining breast tissue underwent whole breast radiation using 3D-CT and 4D-CT simulations. Four different types of CT pictures were created for the 4D-CT plan, including images taken using the maximal intensity projection (MIP), average intensity projection (AIP), and photos taken at the end of inspiration and expiration of the clinical target volume (CTV) and planning target volume (PTV).…”

Impact of different respiratory gating methods on target delineation and a radiotherapy plan for solitary pulmonary tumors

“…In comparison with the traditional non gating 3DCT simulation, the gating method could significantly reduce the irradiation dose to normal lung tissue. IGTV retro and PTV retro , based on retrospective respiratory gating technology, provided more tumor movement information than IGTV pro and PTV pro , whereas Plan retro did not increase the irradiation dose on normal lung tissue significantly 24 …”

Myocardial Ischemia Related to Common Cancer Therapy—Prevention Insights

“…Many improvements to RT protocols have been added, such as enhanced localization and gated techniques. Three- and four-dimensional planning models and those based on positron emission tomography/X-ray computed tomography are widely implemented in practice [ 135 , 138 ]. For patients with left-sided breast cancer, intensity-modulated RT and deep inspiration breath-hold (DIBH) technique are also used to reduce the harmful effect of radiation [ 139 , 140 , 141 , 142 ].…”