Journal of Experimental & Clinical Cancer Research 2009, 28:2 http://www.jeccr.com/content/28/1/2 rFDiioogrsuefriedelids2tprilbanut(iCon)s in one case for ICRUrp single field plan (A), IBMCrp single field plan (B) and two opposed anterior-poste- Dose distributions in one case for ICRUrp single field plan (A), IBMCrp single field plan (B) and two opposed anterior-posterior field plan (C). ICRUrp, the International Commission on Radiation Units and Measurements reference point; IBMCrp, the International Bone Metastasis Consensus Working Party reference point. The isodose lines are shown as follows: 75% (blue), 80% (yellow), 90% (dark blue), 95% (red), 100 (pink), 110% (green), 115% (orange). cally significant. Values are expressed as mean (range) ± standard deviation (SD). Results Dose ranges of the PTVs for all plans are shown in Table 1. AP-PA field plans achieved the intended dose ranges and homogeneity for PTVs, unlike the single posterior field plans. Minimum doses of both single posterior field plans were significantly lower (p < 0.001) while maxi- mum doses were significantly higher (p < 0.001) than AP- PA field plans. Minimum, maximum and mean doses were higher in IBMCrp single field plans with an increased dose heterogeneity than in ICRUrp single field plans (p < 0.001). The mean depth of the PTV from skin surface in the cen- tral plane was 9.8 (7.4–13.5) ± 1.1 cm and the mean patient thickness was 22.1 (14.4–29.1) ± 3.7 cm. Only in two plans were the ICRUrps and IBMCrps located at the same sites, which were in the mid-vertebral body. Of 45 ICRUrps, 35 were located on the medulla spinalis behind the vertebral body and 8 were located in the posterior 1/3 of the vertebral body. None of the ICRUrps were located in the anterior half of the vertebral body or anterior to the vertebral body. The mean dose, expressed as percentages of the prescribed dose, to the portion of the esophagus in the thoracic radi- otherapy fields was 78.6% (70–85%) ± 4.1% in the ICRUrp single field plans, 84.6% (74–92%) ± 5.5% in the IBMCrp single field plans and 94.5% (87–99%) ± 3.1% in the AP-PA field plans. The mean dose to the intestines located in the lumbar radiotherapy fields was 66.2% (58– 78%) ± 5.1% in the ICRUrp single field plans, 73.1% (64– 88%) ± 6.2% in the IBMCrp single field plans and 90.8% (82–99%) ± 3.7% in the AP-PA fields plans. The mean doses to the esophagus and intestines were higher in the AP-PA field plans than in the single posterior field plans (p < 0.001). Dose ranges to the medulla spinalis for all plans are shown in Table 2. The mean doses to the medulla spinalis were lower in the AP-PA field plans than in the single pos- terior field plans (p < 0.001).In all IBMCrp single field Page 4 of 7 (page number not for citation purposes)