Murat KÖYLÜ, Deniz YALMAN, Yavuz ANACAK, İbrahim OLACAK, Serra KAMER, Onur ÜNLENEN, Nezahat OLACAK

Evaluation of Dose Distribution in Field Junction Area and Risk Organs for Supine and Prone Treatment Techniques in Craniospinal Irradiation

OBJECTIVE The aim of this study is to investigate dose distributions in junction regions and organs at risk in asymmetric collimation techniques and divergence matching techniques used in craniospinal treatments. METHODS In the anthropomorphic phantom, the junction area and organ at risk doses were determined for eight different craniospinal irradiation (CSI) techniques with the help of thermoluminescent dosimeter (TLD) and treatment planning system (TPS). These techniques differ in terms of the parameters of the table being angled/un-angled, using block/multi-leaf collimator, and being in supine/prone position. RESULTS There was no statistically significant difference between TPS and TLD doses of all techniques. The lowest doses of cribriform plate are 1.82 Gy in PM, and 1.84 Gy in PAM. The lowest dose in lenses is 0.19 Gy in PB. The lowest dose of thyroid is 1.27 Gy in PB and highest dose of PAM is 1.35 Gy. Average small intestine dose of 1.92 Gy in non-table angle decreases to 1.08 Gy with table angle. The highest kidney doses are 0.14 Gy in SM. Ovaries take an average dose of 0.09 Gy in non-table angled and average of 0.13 Gy in table-angled techniques. CONCLUSION It has been determined that CSI technique in supine without table angle and protected with special blocks, is superior to other techniques due to its better dose homogeneity in treatment volume, providing immobilization in daily use and ease of application.

PDF

___

1. Özkan A.K. Kranyospinal Işınlama Tekniklerinin Yüzüstü Ve Sırtüstü Pozisyonlarda Karşılaştırılması. Hacettepe Üniversitesi Sağlık Bilimleri Enstitüsü Radyoterapi Fiziği Programı Yüksek Lisans Tezi; 2005.
2. Stripay JL, Merchant TE, Roussel MF, Tinkle CL. Preclinical models of craniospinal ırradiation for medulloblastoma. Cancers 2020;12(1):133.
3. Seravalli E, Bosman M, Lassen-Ramshad Y, Vestergaard A, Oldenburger F, Visser J, et al. Dosimetric comparison of five different techniques for craniospinal irradiation across 15 European centers: analysis on behalf of the SIOPE-BTG (radiotherapy working group). Acta Oncol 2018;57(9):1240–9.
4. Chan AW, Tarbell NJ, Black PM, Louis DN, Frosch MP, Ancukiewicz M, et al. Adult medulloblastoma: Prognostic factors and patterns of relapse. Neurosurgery 2000;47(3):623–32.
5. Yap BK, Magee B, Vollans SE. Craniospinal radiotherapy for medulloblastoma in a man with severe kyphoscoliosis. Clin Oncol 2001;13(2):117–9.
6. Tatcher M, Glicksman AS. Field matching considerations ın craniospinal ırradiation. Int J Radiat Oncol Biol Phys 1989;17(4):865–9.
7. Bernier V. Technical aspectsin cerebrospinal ırradiation. Pediatr Blood Cancer 2004;42(5):447–51.
8. Tinkler SD, Lucraft HH. Are moving junctions ın craniospinal ırradiation for medulloblastoma really necessary? Br J Radiol 1995;68(811):736–9.
9. Parker WA, Freeman CR. A simple technique for craniospinal radiotherapy ın the supine position. Radiother Oncol 2006;78(2):217–22.
10. Narayana A, Jeswani S, Paulino AC. The cranial-spinal junction ın medulloblastoma: Does ıt matter? Int J Radiat Oncol Biol Phys 1999;44(1):81–4.
11. Fernanda LO. Dose evaluation in craniospinal radiotherapy for medullablastoma. Federal University of Pernambuco Center of Technology and Geosciences Department of Nuclear Energy. Brazil April Scientia Plena 2007;3(7):275–8.
12. Meltem A. Baş-Boyun Radyoterapisinde Lineer Hızlandırıcıda Asimetrik Kolimasyonlu Tek İzomerkezli Tedavi Tekniği İle Kobalt-60 Ve Lineer Hızlandırıcıda Normal Kolimasyonlu İki İzomerkezli Tedavi Tekniklerinin Karşılaştırılması. Ankara: Hacettepe Üniversitesi Sağlık Bilimleri Enstitüsü; 2006.
13. Adir L. Spinal radiotherapy for the pediatric patient. Indications, special technical considerations, and longterm consequences. In: McLain RF, Lewandrowski KU, Markman M, Bukowski RM, Macklis R, Benzel EC, editors. Cancer in the Spine. Current Clinical Oncology. New York: Humana Press-Springer; 2006. p. 197–204.
14. Hood C, Kron T, Hamilton C, Callan S, Howlett S, Alvaro F, et al. Correlation of 3D-planned and measured dosimetry of photon and electron craniospinal radiation ın a pediatric anthropomorphic phantom. Radiother Oncol 2005;77(1):111–6.
15. Lee CT, Bilton SD, Famiglietti RM, Riley BA, Mahajan A, Chang EL, et al. Treatment planning with protons for pediatric retinoblastoma, medulloblastoma, and pelvic sarcoma: How do protons compare with other conformal techniques? Int J Radiat Oncol Biol Phys 2005;63(2):362–72.