جستجوی پزشکان

tomographic

tomographic
چهارشنبه ۲۷ آبان ۱۳۹۴

Computerized tomographic simulation compared with clinical mark-up in palliative radiotherapy: A prospective study

Presented in the Canadian Association of Radiation Oncology (CARO) 2004 Annual Scientific Meeting, Halifax, Nova Scotia, Canada.

Peiman Haddad, M.D., Fred Cheung, Ph.D. ,  Gregory Pond, M.Sc.,  Debbie Easton, M.R.T.T. ,  Frederick Cops, M.R.T.T. , Andrea Bezjak, M.D., M.Sc., F.R.C.P.C. , Michael McLean, M.D., F.R.C.P.C., Wilfred Levin, M.B.Ch.B., F.R.C.P.C. ,  Susan Billingsley, B.Sc., M.R.T.T. ,  Diane Williams, R.N., M.N. , Rebecca Wong, M.B.Ch.B., F.R.C.P.C.

Purpose To evaluate the impact of computed tomographic (CT) planning in comparison to clinical mark-up (CM) for palliative radiation of chest wall metastases.

Methods and Materials 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.

tomographic

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 ≥۸۰% of the dose was 5.4% in CM and 9.3% in CT plans (p = ۰٫۰۱۷). 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.

Keywords:

CT simulation, Clinical mark-up, Under-coverage, Palliative radiotherapy, Bone metastases

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