TY - JOUR
T1 - Optimal normal tissue sparing in craniospinal axis irradiation using IMRT with daily intrafractionally modulated junction(s)
AU - Kusters, Johannes M.A.M.
AU - Louwe, Rob J.W.
AU - Van Kollenburg, Peter G.M.
AU - Kunze-Busch, Martina C.
AU - Gidding, Corrie E.M.
AU - Van Lindert, Erik J.
AU - Kaanders, Johannes H.A.M.
AU - Janssens, Geert O.R.J.
PY - 2011/12/1
Y1 - 2011/12/1
N2 - Purpose: To develop a treatment technique for craniospinal irradiation using intensity-modulated radiotherapy (IMRT) with improved dose homogeneity at the field junction(s), increased target volume conformity, and minimized dose to the organs at risk (OARs). Methods and Materials: Five patients with high-risk medulloblastoma underwent CT simulation in supine position. For each patient, an IMRT plan with daily intrafractionally modulated junction(s) was generated, as well as a treatment plan based on conventional three-dimensional planning (3DCRT). A dose of 39.6 Gy in 22 daily fractions of 1.8 Gy was prescribed. Dose-volume parameters for target volumes and OARs were compared for the two techniques. Results: The maximum dose with IMRT was <107% in all patients. V <95 and V >107 were <1 cm 3 for IMRT compared with 3-9 cm 3 for the craniospinal and 26-43 cm 3 for the spinal-spinal junction with 3DCRT. These observations corresponded with a lower homogeneity index and a higher conformity index for the spinal planning target volume with IMRT. IMRT provided considerable sparing of acute and late reacting tissues. V 75 for the esophagus, gastroesophageal junction, and intestine was 81%, 81%, and 22% with 3DCRT versus 5%, 0%, and 1% with IMRT, respectively. V 75 for the heart and thyroid was 42% and 32% vs. 0% with IMRT. Conclusion: IMRT with daily intrafractionally modulated junction results in a superior target coverage and junction homogeneity compared with 3DCRT. A significant dose reduction can be obtained for acute as well as late-reacting tissues.
AB - Purpose: To develop a treatment technique for craniospinal irradiation using intensity-modulated radiotherapy (IMRT) with improved dose homogeneity at the field junction(s), increased target volume conformity, and minimized dose to the organs at risk (OARs). Methods and Materials: Five patients with high-risk medulloblastoma underwent CT simulation in supine position. For each patient, an IMRT plan with daily intrafractionally modulated junction(s) was generated, as well as a treatment plan based on conventional three-dimensional planning (3DCRT). A dose of 39.6 Gy in 22 daily fractions of 1.8 Gy was prescribed. Dose-volume parameters for target volumes and OARs were compared for the two techniques. Results: The maximum dose with IMRT was <107% in all patients. V <95 and V >107 were <1 cm 3 for IMRT compared with 3-9 cm 3 for the craniospinal and 26-43 cm 3 for the spinal-spinal junction with 3DCRT. These observations corresponded with a lower homogeneity index and a higher conformity index for the spinal planning target volume with IMRT. IMRT provided considerable sparing of acute and late reacting tissues. V 75 for the esophagus, gastroesophageal junction, and intestine was 81%, 81%, and 22% with 3DCRT versus 5%, 0%, and 1% with IMRT, respectively. V 75 for the heart and thyroid was 42% and 32% vs. 0% with IMRT. Conclusion: IMRT with daily intrafractionally modulated junction results in a superior target coverage and junction homogeneity compared with 3DCRT. A significant dose reduction can be obtained for acute as well as late-reacting tissues.
KW - Craniospinal irradiation
KW - IMRT
KW - Intrafractionally modulated junction
UR - http://www.scopus.com/inward/record.url?scp=81855180759&partnerID=8YFLogxK
U2 - 10.1016/j.ijrobp.2010.07.1987
DO - 10.1016/j.ijrobp.2010.07.1987
M3 - Article
C2 - 21300472
AN - SCOPUS:81855180759
SN - 0360-3016
VL - 81
SP - 1405
EP - 1414
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 5
ER -