Abstract
In intensity modulated radiation therapy (IMRT) of cervical cancer, uterine motion can be larger than cervix motion, requiring a larger clinical target volume to planning target volume (CTV-to-PTV) margin around the uterine fundus. This work simulates different motion models and margins to estimate the dosimetric consequences. A virtual study used image sets from ten patients. Plans were created with uniform margins of 1 cm (PTVA) and 2.4 cm (PTVC), and a margin tapering from 2.4 cm at the fundus to 1 cm at the cervix (PTVB). Three inter-fraction motion models (MM) were simulated. In MM1, all structures moved with normally distributed rigid body translations. In MM2, CTV motion was progressively magnified as one moved superiorly from the cervix to the fundus. In MM3, both CTV and normal tissue motion were magnified as in MM2, modeling the scenario where normal tissues move into the void left by the mobile uterus. Plans were evaluated using static and percentile DVHs. For a conventional margin (PTVA), quasi-realistic uterine motion (MM3) reduces fundus dose by about 5 Gy and increases normal tissue volumes receiving 30-50 Gy by ∼5%. A tapered CTV-to-PTV margin can restore fundus and CTV doses, but will increase normal tissue volumes receiving 30-50 Gy by a further ∼5%.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2887-2901 |
| Number of pages | 15 |
| Journal | Physics in Medicine and Biology |
| Volume | 56 |
| Issue number | 10 |
| DOIs | |
| State | Published - May 21 2011 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology
Cite this
The effect of uterine motion and uterine margins on target and normal tissue doses in intensity modulated radiation therapy of cervical cancer. / Gordon, J. J.; Weiss, E.; Abayomi, O. K.; Siebers, J. V.; Dogan, Nesrin.
In: Physics in Medicine and Biology, Vol. 56, No. 10, 21.05.2011, p. 2887-2901.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The effect of uterine motion and uterine margins on target and normal tissue doses in intensity modulated radiation therapy of cervical cancer
AU - Gordon, J. J.
AU - Weiss, E.
AU - Abayomi, O. K.
AU - Siebers, J. V.
AU - Dogan, Nesrin
PY - 2011/5/21
Y1 - 2011/5/21
N2 - In intensity modulated radiation therapy (IMRT) of cervical cancer, uterine motion can be larger than cervix motion, requiring a larger clinical target volume to planning target volume (CTV-to-PTV) margin around the uterine fundus. This work simulates different motion models and margins to estimate the dosimetric consequences. A virtual study used image sets from ten patients. Plans were created with uniform margins of 1 cm (PTVA) and 2.4 cm (PTVC), and a margin tapering from 2.4 cm at the fundus to 1 cm at the cervix (PTVB). Three inter-fraction motion models (MM) were simulated. In MM1, all structures moved with normally distributed rigid body translations. In MM2, CTV motion was progressively magnified as one moved superiorly from the cervix to the fundus. In MM3, both CTV and normal tissue motion were magnified as in MM2, modeling the scenario where normal tissues move into the void left by the mobile uterus. Plans were evaluated using static and percentile DVHs. For a conventional margin (PTVA), quasi-realistic uterine motion (MM3) reduces fundus dose by about 5 Gy and increases normal tissue volumes receiving 30-50 Gy by ∼5%. A tapered CTV-to-PTV margin can restore fundus and CTV doses, but will increase normal tissue volumes receiving 30-50 Gy by a further ∼5%.
AB - In intensity modulated radiation therapy (IMRT) of cervical cancer, uterine motion can be larger than cervix motion, requiring a larger clinical target volume to planning target volume (CTV-to-PTV) margin around the uterine fundus. This work simulates different motion models and margins to estimate the dosimetric consequences. A virtual study used image sets from ten patients. Plans were created with uniform margins of 1 cm (PTVA) and 2.4 cm (PTVC), and a margin tapering from 2.4 cm at the fundus to 1 cm at the cervix (PTVB). Three inter-fraction motion models (MM) were simulated. In MM1, all structures moved with normally distributed rigid body translations. In MM2, CTV motion was progressively magnified as one moved superiorly from the cervix to the fundus. In MM3, both CTV and normal tissue motion were magnified as in MM2, modeling the scenario where normal tissues move into the void left by the mobile uterus. Plans were evaluated using static and percentile DVHs. For a conventional margin (PTVA), quasi-realistic uterine motion (MM3) reduces fundus dose by about 5 Gy and increases normal tissue volumes receiving 30-50 Gy by ∼5%. A tapered CTV-to-PTV margin can restore fundus and CTV doses, but will increase normal tissue volumes receiving 30-50 Gy by a further ∼5%.
UR - http://www.scopus.com/inward/record.url?scp=79955420593&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79955420593&partnerID=8YFLogxK
U2 - 10.1088/0031-9155/56/10/001
DO - 10.1088/0031-9155/56/10/001
M3 - Article
C2 - 21490387
AN - SCOPUS:79955420593
VL - 56
SP - 2887
EP - 2901
JO - Physics in Medicine and Biology
JF - Physics in Medicine and Biology
SN - 0031-9155
IS - 10
ER -