Comparison of simulator-CT versus simulator fluoroscopy versus surface marking based radiation treatment planning: a prospective study by three-dimensional evaluation.
OBJECTIVE
Field placement for Radiation Treatment Planning can be done based on the surface markings or simulator fluoroscopy or simulator with CT facilities. A prospective study was carried out to compare these three techniques of radiation treatment planning to quantitatively find out the difference in normal tissue dosages and target volume coverage in the three groups after three-dimensional evaluation.


METHODS
The CT scans of 30 patients in the treatment position, taken on a Shimadzu SCT-3000 TF scanner at 1cm intervals, were transferred to Theraplan-500 three-dimensional radiation treatment planning computer. The normal tissues and target volumes (GTV and CTV) were outlined on all the CT slices as per (ICRU) Report no. 50. Three types of radiation treatment planning was done sequentially: Plan I-based on the surface markings alone, Plan II-based on simulator-fluoroscopy, and Plan III-based on Simulator-CT.


RESULTS
The mean dose to 95% of the clinical target volume (D95) was increased by 4.4 and 6.4% by Plans II and III as compared with Plan I. The mean dose to 3/3rd (D(3/3)) to all the critical organs was decreased by 6.6 and 8.4% by Plans II and III as compared to Plan I. The mean time, in simulator room, for field placement for Plans I-III was 6.2, 14.6 and 44 min, respectively.


CONCLUSIONS
Thus for adequate coverage of target volumes and sparing normal tissues, Simulator-CT based radiation treatment planning is the best method of radiation treatment planning though it is more time consuming.
Suhag
Virender
V
Department of Radiotherapy, Pt. B.D. Sharma Postgraduate Institute of Medical Sciences, Haryana, India. vkaushal2003@yahoo.com
Kaushal
Vivek
V
Yadav
Rohtash
R
Das
Bhagwat Parsad
BP
D000328:Adult; D000368:Aged; D003198:Computer Simulation; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000532:radiotherapy*; D011446:Prospective Studies; D011832:Radiation Injuries / Q000517:prevention & control*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed