Computerized tomographic simulation compared with clinical mark-up in palliative radiotherapy: a prospective study.
OBJECTIVE
To evaluate the impact of computed tomographic (CT) planning in comparison to clinical mark-up (CM) for palliative radiation of chest wall metastases.


METHODS
In patients treated with CM for chest wall bone metastases (without conventional simulation/fluoroscopy), two consecutive planning CT scans were acquired with and without an external marker to delineate the CM treatment field. The two sets of scans were fused for evaluation of clinical tumor volume (CTV) coverage by the CM technique. Under-coverage was defined as the proportion of CTV not covered by the CM 80% isodose.


RESULTS
Twenty-one treatments (ribs 17, sternum 2, and scapula 2) formed the basis of our study. Due to technical reasons, comparable data between CM and CT plans were available for 19 treatments only. CM resulted in a mean CTV under-coverage of 36%. Eleven sites (58%) had an under-coverage of >20%. Mean volume of normal tissues receiving >/=80% of the dose was 5.4% in CM and 9.3% in CT plans (p = 0.017). Based on dose-volume histogram comparisons, CT planning resulted in a change of treatment technique from direct apposition to a tangential pair in 7 of 19 cases.


CONCLUSIONS
CT planning demonstrated a 36% under-coverage of CTV with CM of ribs and chest wall metastases.
Haddad
Peiman
P
Palliative Radiation Oncology Program, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada.
Cheung
Fred
F
Pond
Gregory
G
Easton
Debbie
D
Cops
Frederick
F
Bezjak
Andrea
A
McLean
Michael
M
Levin
Wilfred
W
Billingsley
Susan
S
Williams
Diane
D
Wong
Rebecca
R