The role of protons in modern and biologically-guided radiotherapy

Figures & data

Figure 1. Treatment plans for a T2N2M0 anal cancer. The prescribed dose was 60 CGy to the primary tumour and an inguinal lymph node on the right side with verified involvement and 46 CGy to the rest of the elective volume. Figure 1a shows the dose distribution obtained with IMPT and Figure 1b the dose distribution with Tomotherapy Hi Art.

Figure 2. Dose Volume Histogram for the IMPT proton plan and the Tomotherapy plan for a) the union of the planning target volumes and b) for the total volume, including the PTVs.

Table I. Comparison between the doses (in Cobalt equivalent Gy) and integral doses (I.D. in Joule) for the pelvis patient. The integral dose to the non-involved tissues was reduced by 56% with the IMPT plan compared to the Tomotherapy plan.

	Dose (CGy)
	Min	Max	Mean	Median	Volume	I.D.(J)
Tomo
Target	39.44	63.45	50.93	48.02	1.81	92
External	0.61	63.45	23.95	21.82	16.87	404
Ext - Target			20.72		15.06	312
Protons
Target	42.05	62.77	49.74	46.47	1.81	90
External	0.00	63.56	13.53	2.76	16.87	228
Ext - Target			9.16		15.06	138

Figure 3. Treatment plans for a T1N2cM0 floor of mouth tumour. The primary PTV was prescribed to a dose of 68 CGy and the nodes to 54 CGy Figure 3a shows the dose distribution obtained with IMPT and Figure 3b the dose distribution with IMRT.

Table II. Comparison between the doses (in Cobalt equivalent Gy) and integral doses (I.D. in Joule) for the Head & Neck patient. The integral dose to the non-involved tissues was reduced by 65% with the IMPT plan compared to the Tomotherapy plan.

	Dose (CGy)
	Min	Max	Mean	Median	Volume	I.D.(J)
IMRT
Target	30.1	73.1	64.39	–	0.54	34.8
External	0.00	73.2	12.66	–	16.64	211
Ext - Target			10.92	–	16.10	176.2
Protons
Target	42.7	71.2	61.9	–	0.54	33.5
External	0.00	72.9	5.73	–	16.64	95.3
Ext – Target			3.84		16.10	61.8