TABLE 1. Comparison Between Intra- and Inter-Fractional Variations.

Variation Type	Intra-fraction	Inter-fraction
Time of Occurrence	During a single fraction [17], [19]–[23]	Between different fractions [19], [20], [22], [23]
Time Scale	Seconds to minutes [18]	Hours or day-to-day level [17], [18], [21]
Motion Coverage	Internal organ motion, breathing, swallowing [21], [22]	Position changes of patients, patient weight gain/loss, internal organ motion, breathing, swallowing [21], [22]