TY - JOUR
T1 - Evaluating mobility for radiotherapy planning of lung tumors
T2 - A comparison of virtual fluoroscopy and 4DCT
AU - van der Geld, Ylanga G.
AU - Senan, Suresh
AU - van Sörnsen de Koste, John R.
AU - van Tinteren, Harm
AU - Slotman, Ben J.
AU - Underberg, René W.M.
AU - Lagerwaard, Frank J.
PY - 2006/7
Y1 - 2006/7
N2 - Purpose: Fluoroscopy is widely used for evaluating tumor mobility in radiotherapy planning. Lung tumor mobility was scored using virtual fluoroscopy, and this was compared to mobility derived from contoured tumors in all phases of a respiration-correlated (or 4D) CT scan. Methods and materials: 4DCT datasets were reviewed and 29 patients were identified in whom tumors were visible on anterior-posterior fluoroscopy views. Mobility in all directions was estimated on fluoroscopy movie loops by four clinicians. These results were compared to mobility measured from contoured tumor volumes in all phases of the same 4DCT. Internal target volumes (ITV) were generated for both approaches. Results: In eight patients, fluoroscopy did not allow for tumor mobility to be assessed in at least one direction. No significant inter-clinician variation was observed with respect to fluoroscopic assessment of mobility. Clinicians systematically overestimated mobility in all three directions (p < 0.05). The mean ITVs derived using fluoroscopy were 52.2% larger than those derived using 4DCT contours, but the individual ITVs were smaller in three patients. Conclusion: Use of virtual fluoroscopy generally overestimates the mobility of visible lung tumors, and results in irradiation of unnecessarily large target volumes. In contrast, use of 4DCT minimizes the risk of normal tissue toxicity.
AB - Purpose: Fluoroscopy is widely used for evaluating tumor mobility in radiotherapy planning. Lung tumor mobility was scored using virtual fluoroscopy, and this was compared to mobility derived from contoured tumors in all phases of a respiration-correlated (or 4D) CT scan. Methods and materials: 4DCT datasets were reviewed and 29 patients were identified in whom tumors were visible on anterior-posterior fluoroscopy views. Mobility in all directions was estimated on fluoroscopy movie loops by four clinicians. These results were compared to mobility measured from contoured tumor volumes in all phases of the same 4DCT. Internal target volumes (ITV) were generated for both approaches. Results: In eight patients, fluoroscopy did not allow for tumor mobility to be assessed in at least one direction. No significant inter-clinician variation was observed with respect to fluoroscopic assessment of mobility. Clinicians systematically overestimated mobility in all three directions (p < 0.05). The mean ITVs derived using fluoroscopy were 52.2% larger than those derived using 4DCT contours, but the individual ITVs were smaller in three patients. Conclusion: Use of virtual fluoroscopy generally overestimates the mobility of visible lung tumors, and results in irradiation of unnecessarily large target volumes. In contrast, use of 4DCT minimizes the risk of normal tissue toxicity.
KW - 4DCT scan
KW - Fluoroscopy
KW - Radiotherapy planning
KW - Tumor mobility
UR - http://www.scopus.com/inward/record.url?scp=33744821891&partnerID=8YFLogxK
U2 - 10.1016/j.lungcan.2006.03.013
DO - 10.1016/j.lungcan.2006.03.013
M3 - Article
C2 - 16698115
AN - SCOPUS:33744821891
SN - 0169-5002
VL - 53
SP - 31
EP - 37
JO - Lung Cancer
JF - Lung Cancer
IS - 1
ER -