Challenges in using 18 F-fluorodeoxyglucose-PET-CT to define a biological radiotherapy boost volume in locally advanced pancreatic cancer

Table 1 Pre- and Post-treatment SUV _max values and absolute volumes of the gross tumour volume (GTV) and volumes derived from segmentation of the pre- and post-treatment FDG-PET/CTs

Patient number	Pre-treatment SUV_max	Post-treatment SUV_max	Absolute volumes (cm³)
			GTV	Pre40%	Pre50%	Post90%	Post80%	Post70%	Post60%
1	7.6	4.2	57.6	28.9	19.8	0.2	1.6	6.9	14.7
2	8.4	7.2	80.2	31.6	18.7	0.1	0.3	1.7	16.7
3	6.4	mCR	14.5	7.4	3.8
4	10.6	5.7	41.9	15.6	9.0	0.1	0.6	2.3	4.9
5	15.6	6.2	44.9	15.7	10.5	0.1	0.1	0.9	2.6
6	13.2	±	55.2	8.1	3.4
7	6.2	3.6	38.0	22.4	12.1	0.1	0.3	1.6	4.4
8	11.9	7.5	27.2	13.4	5.4	0.1	0.6	1.4	2.6
9	4.0	7.9	28.6	§	§	§	§	§	§
10	9.1	mCR	49.9	34.2	9.2
11	10.0	mCR	19.3	4.8	2.5
12	9.4	mCR	14.0	6	3.2
13	¢	¢	10.6	¢	¢	¢	¢	¢	¢
14	4.1	2.5	22.3	11.0	5.9	0.1	0.3	2.2	4.0
15	¤	¤	40.8	¤	¤	¤	¤	¤	¤
16	9.3	5.1	32.9	21.8	15.7	0.2	1.3	4	7.6
17	6.5	3.2	26.6	19.0	11.8	0.2	1.6	5.5	11.4
Median	8.0***	3.6*** P < 0.001
Mean^			41.3	19.9	12.1	0.1	0.7	2.9	7.7

mCR metabolic complete response. ¢ Not FDG avid. § Diffuse FDG uptake making delineation of a ROI impossible. ¤ Elevated serum glucose, scans therefore could not be interpreted. ± Not done. *Difference in pre- and post-treatment SUV_max p = 0.0006. ^only values included in spatial correlation analysis included.

ISSN: 1748-717X