Baş Boyun Kanserlerinde Adaptif Radyoterapinin Doz Hacim Histogramı ve Termolüminesans Dozimetreler ile Değerlendirilmesi
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Dosyalar
Tarih
2022
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Selçuk Üniversitesi Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Baş boyun kanserli hastalar radyoterapi sırasında tümör ve kritik organ hacimlerinde anatomik değişikliklere uğramaktadır. Bu durum, hedef hacmin yetersiz doz almasına veya normal dokuların aşırı radyasyona maruz kalmasına neden olmaktadır. Baş boyun kanserlerinin radyoterapisi sırasında hastada bölgesel kontrolü artırmak ve komplikasyonları azaltmak için belirlenen dozun doğru uygulanması büyük önem taşımaktadır. Baş boyun bölgesinde yüzeysel doz ölçümü almanın bazı zorlukları vardır fakat boyun bölgesindeki cilt dozunun doğru bilinmesi klinik kararlara yardımcı olmaktadır. Akut cilt reaksiyonlarını ve toksisiteleri en aza indirmek için boyun bölgesinde cilt dozunun doğru tahmini önemlidir. Bu çalışmanın amacı, baş boyun kanserleri için 3 fazlı adaptif radyoterapi (ART) tekniğinin dozimetrik faydalarını değerlendirmektir. Ayrıca termolüminesan dozimetreler (TLD) ile radyasyon tedavisi sırasında hastalarda meydana gelen anatomik değişikliklere bağlı olarak cilt dozundaki değişikliklerin incelenmesi ve tedavi planlama sisteminin (TPS) cilt dozundaki doz hesaplama doğruluğunun değerlendirilmesi amaçlanmıştır. Bu çalışmaya baş boyun kanserli 15 hasta dahil edilmiştir. Hastanın boynuna artefakt yapmayan doku eşdeğeri materyaller, bilgisayarlı tomografi (BT) sırasında belirlenen 5 farklı noktaya yerleştirilmiştir. Radyoterapi planları, tüm hastalara 33 fraksiyonda günlük doz 2.12 Gy olacak şekilde toplamda 69.96 Gy simultaneous-integrated boost (SIB) tekniği ile yapılmıştır. İn vivo doz ölçümleri için 3.2 × 3.2 × 0.89 mm TLD-100 (LiF: Mg, Ti) çipleri kullanıldı. Tedavi sırasında cilt doz artışı %10'dan fazla ve kilo kaybı %5'ten fazla olan hastalara kontrol BT'si önerilmiştir. Hastada kilo kaybı ve cilt dozu artışı nedeniyle kontrol BT'leri BT14 ve BT24 elde edilmiştir. Offline ART planları 14 ve 24. fraksiyondan sonra oluşturuldu ve daha sonraki işlemler için kullanıldı (sırasıyla APlan1 ve APlan2). Çalışmaya dahil edilen tüm hastalara 3 aşamalı ART uygulanmıştır. Buna göre sırasıyla 0-14, 15-24 ve 25-33 fraksiyonları arasında Plan0 Aplan1 ve Aplan2 uygulanmıştır. Adaptif (ART: Plan0+Aplan1+Aplan2) ve adaptif olmayan (Non-ART) planlar için doz-hacim histogramları (DVH'ler) karşılaştırıldı. Lateral boyun çapı (LBÇ) değişimi BT14 ve BT24 için sırasıyla %7,35 (p<0,001) ve %5,44 (p<0,001) azalma ile istatistiksel olarak anlamlı bulunmuştur. BT0'a kıyasla BT14 için ortalama kilo kaybı %7,80 ve BT14'e kıyasla BT24'deki kilo kaybı %5,65 olarak bulunmuştur. Cilt dozu artışı Plan0, Aplan1 ve Aplan2 için sırasıyla %15.25, %10.56 ve %2.83 olarak ölçülmüştür. ART için ipsilateral parotis ve kontralateral parotis Dmean dozlarının sırasıyla 1,62 Gy (p<0,001) ve 2,25 Gy (p<0,001) azaltıldığı görülmüştür. Tedavi sırasında cilt dozundaki %10'dan fazla artış ve %5'ten fazla kilo kaybı ART'nin uygulanması için belirleyici bir nokta olarak düşünülmelidir. Baş boyun kanserli hastalarda yoğunluk ayarlı radyoterapi (YART) sırasında 15. ve 25. fraksiyonlardan sonra kontrol BT taramasının yapılması ve yeniden planlanma önerilmektedir. Sonuç olarak, 3 fazlı ART yaklaşımı, baş boyun kanserli hastalarda dozimetrik faydalar sağlamaktadır. Ayrıca planların in vivo ölçümlerle kontrollerinin sıklıkla yapılması radyasyon tedavisi kalitesini artıracaktır.
Head and neck cancer patients undergo anatomical changes in tumor and critical organ volumes during radiotherapy. This causes the target volume to receive an insufficient dose or to expose normal tissues to excessive radiation. Correct application of the determined dose is of great importance in order to increase regional control and reduce complications during radiotherapy of head and neck cancers. There are some difficulties in obtaining a surface dose measurement in the head and neck region, but knowing the correct skin dose in the neck region helps clinical decisions. Accurate estimation of skin dose in the neck area is important to minimize acute skin reactions and toxicities. The aim of this study is to evaluate the dosimetric benefits of the 3-phase adaptive radiotherapy (ART) technique for head and neck cancers. In addition, it is aimed to examine the changes in skin dose depending on the anatomical changes that occur in patients during radiation therapy with thermoluminescent dosimeters (TLD) and to evaluate the accuracy of dose calculation in the skin dose of the treatment planning system (TPS). Fifteen patients with head and neck cancer were included in this study. Tissue-equivalent materials that do not cause artifacts on the patient's neck were placed at 5 different points determined during computed tomography (CT). Radiotherapy plans were made for all patients with a total of 69.96 Gy simultaneous-integrated boost (SIB) technique, with a daily dose of 2.12 Gy in 33 fractions. 3.2 × 3.2 × 0.89 mm TLD-100 (LiF: Mg, Ti) chips were used for in vivo dose measurements. Control CT was recommended for patients with skin dose increase greater than 10% and weight loss greater than 5% during treatment. Control CTs CT14 and CT24 were obtained due to weight loss and increased skin dose in the patient. Offline ART plans were created after fractions 14 and 24 and used for further processing (APlan1 and APlan2, respectively). All patients included in the study received 3-stage ART. Accordingly, Plan0 Aplan1 and Aplan2 were applied between the 0-14, 15-24 and 25-33 fractions, respectively. Dose-volume histograms (DVHs) were compared for adaptive (ART: Plan0+Aplan1+Aplan2) and non-adaptive (Non-ART) plans. The change in lateral neck diameter (LND) was statistically significant with a decrease of 7.35% (p<0.001) and 5.44% (p<0.001) for CT14 and CT24, respectively. The mean weight loss for CT14 compared to CT0 was 7.80% and the weight loss for CT24 versus CT14 was 5.65%. Skin dose increase was measured as 15.25%, 10.56% and 2.83% for Plan0, Aplan1 and Aplan2, respectively. For ART, ipsilateral parotid and contralateral parotid Dmean doses were decreased by 1.62 Gy (p<0.001) and 2.25 Gy (p<0.001), respectively. An increase in skin dose of more than 10% and a weight loss of more than 5% during treatment should be considered a decisive point for the administration of ART. It is recommended to perform a control CT scan and reschedule after the 15th and 25th fractions during intensity modulated radiotherapy (IMRT) in patients with head and neck cancer. In conclusion, the 3-phase ART approach provides dosimetric benefits in patients with head and neck cancer. In addition, frequent controls of plans with in vivo measurements will increase the quality of radiation therapy.
Head and neck cancer patients undergo anatomical changes in tumor and critical organ volumes during radiotherapy. This causes the target volume to receive an insufficient dose or to expose normal tissues to excessive radiation. Correct application of the determined dose is of great importance in order to increase regional control and reduce complications during radiotherapy of head and neck cancers. There are some difficulties in obtaining a surface dose measurement in the head and neck region, but knowing the correct skin dose in the neck region helps clinical decisions. Accurate estimation of skin dose in the neck area is important to minimize acute skin reactions and toxicities. The aim of this study is to evaluate the dosimetric benefits of the 3-phase adaptive radiotherapy (ART) technique for head and neck cancers. In addition, it is aimed to examine the changes in skin dose depending on the anatomical changes that occur in patients during radiation therapy with thermoluminescent dosimeters (TLD) and to evaluate the accuracy of dose calculation in the skin dose of the treatment planning system (TPS). Fifteen patients with head and neck cancer were included in this study. Tissue-equivalent materials that do not cause artifacts on the patient's neck were placed at 5 different points determined during computed tomography (CT). Radiotherapy plans were made for all patients with a total of 69.96 Gy simultaneous-integrated boost (SIB) technique, with a daily dose of 2.12 Gy in 33 fractions. 3.2 × 3.2 × 0.89 mm TLD-100 (LiF: Mg, Ti) chips were used for in vivo dose measurements. Control CT was recommended for patients with skin dose increase greater than 10% and weight loss greater than 5% during treatment. Control CTs CT14 and CT24 were obtained due to weight loss and increased skin dose in the patient. Offline ART plans were created after fractions 14 and 24 and used for further processing (APlan1 and APlan2, respectively). All patients included in the study received 3-stage ART. Accordingly, Plan0 Aplan1 and Aplan2 were applied between the 0-14, 15-24 and 25-33 fractions, respectively. Dose-volume histograms (DVHs) were compared for adaptive (ART: Plan0+Aplan1+Aplan2) and non-adaptive (Non-ART) plans. The change in lateral neck diameter (LND) was statistically significant with a decrease of 7.35% (p<0.001) and 5.44% (p<0.001) for CT14 and CT24, respectively. The mean weight loss for CT14 compared to CT0 was 7.80% and the weight loss for CT24 versus CT14 was 5.65%. Skin dose increase was measured as 15.25%, 10.56% and 2.83% for Plan0, Aplan1 and Aplan2, respectively. For ART, ipsilateral parotid and contralateral parotid Dmean doses were decreased by 1.62 Gy (p<0.001) and 2.25 Gy (p<0.001), respectively. An increase in skin dose of more than 10% and a weight loss of more than 5% during treatment should be considered a decisive point for the administration of ART. It is recommended to perform a control CT scan and reschedule after the 15th and 25th fractions during intensity modulated radiotherapy (IMRT) in patients with head and neck cancer. In conclusion, the 3-phase ART approach provides dosimetric benefits in patients with head and neck cancer. In addition, frequent controls of plans with in vivo measurements will increase the quality of radiation therapy.
Açıklama
Anahtar Kelimeler
Adaptif Radyoterapi, Baş boyun kanseri, Cilt dozu, TLD, Adaptive Radiotherapy, Head and neck cancer, Skin dose
Kaynak
WoS Q Değeri
Scopus Q Değeri
Cilt
Sayı
Künye
Gül, O. V., (2022). Baş Boyun Kanserlerinde Adaptif Radyoterapinin Doz Hacim Histogramı ve Termolüminesans Dozimetreler ile Değerlendirilmesi. (Doktora Tezi). Selçuk Üniversitesi, Fen Bilimleri Enstitüsü, Konya.
