Introduction: The aim of the study was to evaluate organ-at-risk dose sparing in treatment plans for patients with left-sided breast cancer irradiated with Deep Inspiration Breath Hold (DIBH) and Free Breathing (FB) techniques. Material and methods: Twenty patients with left-sided breast cancer were analyzed and divided into two groups. Group A included 10 patients with non-metastatic breast cancer, while group B involved 10 patients with metastatic breast cancer spreading to regional lymph nodes. All patients went through the DIBH coaching. For planning purposes, CT scans were obtained in both DIBH and FB. Mean heart dose (Dmean,heart), mean heart volume receiving 50% of the prescribed dose (V50), V20 (V20L.lung), V10 (V10L.lung) and V5 for left lung (V5L.lung), the volume of the PTV receiving a dose greater than or equal to 95% of the prescribed dose (V95 [%]), the maximum point dose (Dmax), and the volume of PTV receiving 107% of the prescribed dose were reported. Results: In all 20 analyzed pairs of plans, a reduction by more than half in the mean heart dose in DIBH technique plans was achieved, as well as a significant reduction was found in DIBH plans for the heart V50. In 19 patients, the use of the DIBH technique also reduced the volume of the left lung receiving doses of 20 Gy, 10 Gy, and 5 Gy compared to the FB technique. Conclusions: Dosimetric analysis showed that the free breathing plans don’t fulfill the criteria for a mean heart dose (group B) and the left lung receiving a 20 Gy dose (group A) compared to the DIBH plans. Radiation therapy of left breast cancer with the use of the DIBH technique results in a significant dose reduction in the heart and also reduces the dose in the left lung in the majority of patients, compared to the FB procedure.
Celem pracy jest dokonanie analizy porównawczej parametrów rozkładu dawki na swobodnym oddechu (ang. Free breathing, FB) i wstrzymanym głębokim wdechu (ang. Deep inspiration breath-hold, DIBH) dla pacjentek z lewostronnym nowotworem piersi napromienianych techniką VMAT. Praca została wykonana w Narodowym Instytucie Onkologii im. Marii Skłodowskiej-Curie – Państwowym Instytucie Badawczym przy ul. Wawelskiej 15 w Warszawie. Analizę parametrów rozkładu dawki przeprowadzono na grupie 30 pacjentek napromienianych na obszar blizny po mastektomii oraz na obszar loży pooperacyjnej. Plany napromieniania wykonane zostały w systemie planowania leczenia Monaco firmy ELEKTA. Porównanie planów leczenia na swobodnym oddechu i wstrzymanym głębokim wdechu wykazało, że pod względem objęcia targetu żadna z technik nie jest wiodąca. Technika DIBH pozwoliła na zmniejszenie dawki w narządach krytycznych, przede wszystkim w sercu, płucu po stronie napromienianej i lewej tętnicy wieńcowej. Uzyskane redukcje średniej dawki średniej wynosiły: 40,5%, 11,2%, 56,6%, odpowiednio dla serca, płuca lewego i lewej tętnicy wieńcowej. Redukcja V20Gy i V5Gy dla serca wyniosła 91,4 i 56,6%. Dla płuca lewego V20Gy i V10Gy zredukowano o 12,9 i 8,1%, a dawkę maksymalną dla lewej tętnicy wieńcowej o 44,3%.
EN
The aim of the study is to perform a comparative analysis of the dose distribution parameters for free breathing (FB) and deep inspiration breath-hold (DIBH) for patients with left- -sided breast cancer irradiated with the VMAT technique. The work was carried out at the Maria Skłodowska-Curie – National Research Institute at Wawelska 15 Street in Warsaw. The analysis of the dose distribution parameters was carried out on a group of 30 patients irradiated on the scar after mastectomy and on the area after breast-conserving surgery. The irradiation plans were made in the Monaco treatment planning system by ELEKTA. A comparison of treatment plans with free breath and deep breath hold showed that none of the techniques was leading in terms of target acquisition. The DIBH technique allowed for dose reduction in organs at risk, mainly in the heart, lung on the irradiated side and left anterior descending. The obtained mean mean dose reductions were: 40,5%, 11,2%, 56,6% for the heart, left lung and left anterior descending, respectively. The reduction of V20Gy and V5Gy for the heart was 91,4 and 56,6%. For the left lung, V20Gy and V10Gy were reduced by 12,9 and 8,1%, and the maximum dose for the left coronary artery by 44,3%.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.