Evaluation of spinal cord doses in patients with head and neck cancer receiving radiotherapy

Abstract

OBJECTIVES Spinal cord doses were analyzed for head and neck cancer patients receiving radiotherapy with three-field technique. METHODS Eighteen patients (12 males, 6 females) with head and neck carcinoma were evaluated. Spinal cord doses were evaluated for each treatment phase. Biologically effective doses (BED) were calculated for the maximum spinal doses in all patients and compared to the 92 Gy, which was the BED of the spinal cord tolerance dose of 46 Gy. RESULTS The maximum spinal cord dose ranged from 4399 to 4954 cGy. The median dose at the junction of the lateral and anterior fields was 4131 cGy. BED of the maximum spinal doses ranged between 75-98 Gy (median 91), and in seven patients it was over 92 Gy; total spinal dose was over 46 Gy in 13 patients. CONCLUSION Spinal cord doses in each phase should be calculated separately with BED values for assessment of the cumulative spinal cord doses.

Keywords

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Radyoterapi uygulanan baş-boyun kanserli hastalarda medulla spinalis dozlarının incelenmesi

Öz

AMAÇ Üç alan tekniği ile radyoterapi uygulanan baş-boyun kanserli hastalarda medulla spinalis dozları incelendi. GEREÇ VE YÖNTEM Baş-boyun karsinomlu 18 hasta (12 erkek, 6 kadın) retrospektif olarak değerlendirildi. Medulla spinalis dozları tedavinin her fazında ayrı ayrı değerlendirildi ve maksimum medulla spinalis dozu için biyolojik efektif dozlar (BED) hesaplandı. Medulla spinalis tolerans dozu olarak kabul edilen 46 Gy'in BED eşdeğeri olan 92 Gy ile karşılaştırıldı. BULGULAR Maksimum medulla spinalis dozları 4399-4954 cGy arasında değişmekteydi. Lateral ve ön alan birleşim bölgesindeki medyan doz 4131 cGy idi. Maksimum medulla spinalis dozları için BED değerleri 75-98 (medyan 91) cGy arasında değişmekteydi. Toplam medulla spinalis dozu 13 hastda 46 Gy'in üzerinde olmasına karşın, BED eşdeğerleri sadece yedi hastada 92 Gy'in üzerindeydi. SONUÇ Toplam medulla spinalis dozunun değerlendirilmesinde her fazdaki medulla spinalis dozları ayrı ayrı değerlendirilip BED eşdeğerleri de dikkate alınmalıdır.

Anahtar Kelimeler

• Bafl-boyun kanseri, medulla spinalis, radyoterapi, radyoterapi dozu

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