Extra-target doses in children receiving multileaf collimator (MLC) based intensity modulated radiation therapy (IMRT).
OBJECTIVE
To investigate the extra-target doses using intensity modulated radiation therapy (IMRT).


METHODS
Thirteen children underwent multileaf collimator (MLC)-based IMRT. Treatment site was head and neck or brain in eight (Group I), trunk in two (Group II), and abdomen/pelvis in three (Group III). Thermoluminescent dosimeters (TLD) were placed at the thyroid gland, breast, and testis. A control group of seven children received conventional RT and TLD measurements.


RESULTS
For the eight Group I children, the median dose equivalent measurements during the course of IMRT to the thyroid, breast, and testis were 348 mSv, 110 mSv, and 30 mSv, respectively. For the two Group II patients, the measurements to the thyroid ranged from 1,525 to 2,449 mSv while for the testis was 62 mSv. For the Group III patients, the median dose equivalent measurements to the thyroid, breast, and testis were 182 mSv, 406 mSv, and 159 mSv. The median dose equivalent measurements to the thyroid, breast, and testis for Group I children were 300 mSv, 120 mSv, and 75 mSv. The Group II conventional patient had a measurement of 180 mSv, 80 mSv, and 80 mSv to the thyroid, breast, and testis. For the Group III conventional cases, the median dose equivalent measurements were 192 mSv, 496 mSv, and 434 mSv.


CONCLUSIONS
No significant difference was seen in the thyroid and breast doses of children receiving MLC-based IMRT compared to conventional RT for the treatment of head and neck/brain and abdominal/pelvic tumors.
Koshy
Mary
M
Department of Radiation Oncology, Emory Clinic and Emory University, Atlanta, Georgia 30322, USA.
Paulino
Arnold C
AC
Marcus
Robert B
RB
Ting
Joseph Y
JY
Whitaker
Daisy
D
Davis
Lawrence W
LW
D000008:Abdominal Neoplasms / Q000532:radiotherapy; D000293:Adolescent; D001932:Brain Neoplasms / Q000532:radiotherapy; D001940:Breast / Q000528:radiation effects*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy; D006801:Humans; D008297:Male; D010386:Pelvic Neoplasms / Q000532:radiotherapy; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D013737:Testis / Q000528:radiation effects*; D013819:Thermoluminescent Dosimetry; D013961:Thyroid Gland / Q000528:radiation effects*