Gradual Recovery from Nonambulatory Quadriparesis Caused by Metastatic Epidural Cervical Cord Compression in an Octogenarian Gallbladder Carcinoma Patient Treated with Image-Guided Three-Dimensional Conformal Radiotherapy Alone Using a Field-in-Field Technique

Table 1

Beam arrangement (a) and dose-volume histogram data (b).

(a)

	Field (number)	Gantry rotation (°)	Collimator angle (°)	Weight	Illustrations
Initial plan	1	80	0	1.00	Figure 2(g)
	2	125	0	0.07	Figure 2(i)
	3	180	0	0.80
	4	235	0	0.07
	5	280	0	1.00
Boost plan	1	85	0	0.95
	2	85	0	0.07
	3	180	0	0.30	Figure 2(h)
	4	180	90	0.18	Figure 2(j)
	5	275	0	1.00
	6	275	0	0.05

(b)

Spinal cord dose^a
Initial plan (%)	101.6	101.0	100.4	100.0	98.0	77.5
Boost plan (%)	92.6	90.0	82.8	71.5	30.0	4.0
Cumulative BED2 (Gy)	121.6	119.2	114.5	108.3	90.3	57.4
Cumulative BED0.87 (Gy)	232.1	227.3	217.7	205.5	171.1	106.2
2 Gy dose equivalent () (Gy)	60.8	59.6	57.2	54.2	45.1	28.7
2 Gy dose equivalent () (Gy)	70.4	68.9	66.0	62.3	51.9	32.2
GTV dose
Initial plan (%)	98.2	98.8	102.0	102.0	102.3	106.0
Boost plan (%)	44.0	59.0	95.8	95.8	91.5	101.8
Cumulative BED10 (Gy)	42.8	45.7	54.4	54.4	53.7	57.7
2 Gy dose equivalent () (Gy)	35.7	38.0	40.8	45.3	44.7	48.1
PTV dose
Initial plan (%) PTV 168.9 cm^3	90.0	93.0	94.4	99.0	99.2	105.8
Boost plan (%) PTV 42.0 cm^3	86.0	89.7	91.8	97.5	96.8	102.0

: maximum dose, BED: biological effective dose, : mean dose, GTV: gross tumor volume, and PTV: planning target volume. (%) represents the dose (%), relative to the prescribed point (100%), receiving at least % of volume and (%) means the dose (%) receiving at least  cm³ of volume. BED is calculated according to the linear-quadratic formula: (Gy) = total dose × [1 + (dose per fraction)/, where represents the ratio ( for the antitumor effect; and 0.87 for spinal cord), and 2 Gy dose equivalent () is the 2 Gy per fraction equivalent total dose according to the value of . ^aThe spinal cord is expediently contoured as the dural theca.