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.