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Am J Nucl Med Mol Imaging 2012;2(3):307-313
Original Article
The role of PET/CT in decreasing inter-observer variability in treatment planning
and evaluation of response for cervical cancer
Ajay Tejwani, Amir Lavaf, Kapila Parikh, Bahaa Mokhtar, Uma Swamy, Joana Emmolo, Adel Guirguis, Hani Ashamalla
Department of Radiation Oncology, New York Methodist Hospital, Brooklyn, New York; North Florida Cancer Institute, Gainesville,
Florida; Department of Radiation Oncology, Overlook Medical Center, Summit, New Jersey; Weill Cornell School of Medicine, New
York, New York
Received March 20, 2012; accepted April 23, 2012; Epub July 10, 2012; Published July 30, 2012
Abstract: We have previously introduced anatomic biologic contouring (ABC) with PET/CT, using a distinct “halo” to unify contouring
methods in treatment planning for lung and head and neck cancers. The objective of this study is to assess the utility of PET/CT in
planning and treatment response for cervical cancer. Forty-two patients with stages II-IIIB cervix cancer were planned for irradiation
using PET/CT. A CT-based Gross Tumor Volume (GTV-CT) was delineated by two independent observers while the PET remained
obscured. The Planning Target Volume (PTV) was obtained by adding a 1.5 cm margin around the GTV. The same volumes were
recontoured using PET/CT data and termed GTV-ABC and PTV-ABC, respectively. The values of GTV-CT and GTV-ABC and the
absolute differences between the two observers were analyzed. Additionally, 23 of these patients had PET/CT performed 3 months
after treatment. The anatomic biologic value (ABV) was calculated using the product of maximum diameter and mean SUV of the
cervical tumor. The pre- and post-treatment ABVs were compared. A “halo” was observed around areas of maximal SUV uptake. The
mean halo SUV was 1.91 ± 0.56 (SD). The mean halo thickness was 2.12 ± 0.5 (SD) mm. Inter-observer GTV variability decreased
from a mean volume difference of 55.36 cm3 in CT-based planning to 12.29 cm3 in PET/CT-based planning with a respective
decrease in standard deviation (SD) from 55.78 to 10.24 (p <0.001). Comparison of mean pre-treatment and post-treatment ABV’s
revealed a decrease of ABV from 48.2 to 7.8 (p<0.001). PET/CT is a valuable tool in radiation therapy planning and evaluation of
treatment response for cervical cancer. A clearly visualized “halo” was successfully implemented in GTV contouring in cervical
cancer, resulting in decreased inter-observer variability in planning. PET/CT has the ability to quantify treatment response using
anatomic biologic value. (ajnmmi1203003).
Keywords: Cervical cancer, positron emission tomography, PET/CT, treatment planning, inter-observer variability
Address all correspondence to:
Dr. Ajay Tejwani
New York Methodist Hospital
Department of Radiation Oncology
506 Sixth St, Miner Basement, Brooklyn, NY 11215, USA.
Tel: (718) 780-3677; Fax: (718) 780-3637
E-mail: ajaytejwani@gmail.com
Original Article
The role of PET/CT in decreasing inter-observer variability in treatment planning
and evaluation of response for cervical cancer
Ajay Tejwani, Amir Lavaf, Kapila Parikh, Bahaa Mokhtar, Uma Swamy, Joana Emmolo, Adel Guirguis, Hani Ashamalla
Department of Radiation Oncology, New York Methodist Hospital, Brooklyn, New York; North Florida Cancer Institute, Gainesville,
Florida; Department of Radiation Oncology, Overlook Medical Center, Summit, New Jersey; Weill Cornell School of Medicine, New
York, New York
Received March 20, 2012; accepted April 23, 2012; Epub July 10, 2012; Published July 30, 2012
Abstract: We have previously introduced anatomic biologic contouring (ABC) with PET/CT, using a distinct “halo” to unify contouring
methods in treatment planning for lung and head and neck cancers. The objective of this study is to assess the utility of PET/CT in
planning and treatment response for cervical cancer. Forty-two patients with stages II-IIIB cervix cancer were planned for irradiation
using PET/CT. A CT-based Gross Tumor Volume (GTV-CT) was delineated by two independent observers while the PET remained
obscured. The Planning Target Volume (PTV) was obtained by adding a 1.5 cm margin around the GTV. The same volumes were
recontoured using PET/CT data and termed GTV-ABC and PTV-ABC, respectively. The values of GTV-CT and GTV-ABC and the
absolute differences between the two observers were analyzed. Additionally, 23 of these patients had PET/CT performed 3 months
after treatment. The anatomic biologic value (ABV) was calculated using the product of maximum diameter and mean SUV of the
cervical tumor. The pre- and post-treatment ABVs were compared. A “halo” was observed around areas of maximal SUV uptake. The
mean halo SUV was 1.91 ± 0.56 (SD). The mean halo thickness was 2.12 ± 0.5 (SD) mm. Inter-observer GTV variability decreased
from a mean volume difference of 55.36 cm3 in CT-based planning to 12.29 cm3 in PET/CT-based planning with a respective
decrease in standard deviation (SD) from 55.78 to 10.24 (p <0.001). Comparison of mean pre-treatment and post-treatment ABV’s
revealed a decrease of ABV from 48.2 to 7.8 (p<0.001). PET/CT is a valuable tool in radiation therapy planning and evaluation of
treatment response for cervical cancer. A clearly visualized “halo” was successfully implemented in GTV contouring in cervical
cancer, resulting in decreased inter-observer variability in planning. PET/CT has the ability to quantify treatment response using
anatomic biologic value. (ajnmmi1203003).
Keywords: Cervical cancer, positron emission tomography, PET/CT, treatment planning, inter-observer variability
Address all correspondence to:
Dr. Ajay Tejwani
New York Methodist Hospital
Department of Radiation Oncology
506 Sixth St, Miner Basement, Brooklyn, NY 11215, USA.
Tel: (718) 780-3677; Fax: (718) 780-3637
E-mail: ajaytejwani@gmail.com
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