1887
banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
Cumulative sum method in nonzero fixed action level setup correction strategy: An application of statistical process control for targeted prostate radiotherapy
Rent:
Rent this article for
USD
10.1118/1.4705349
/content/aapm/journal/medphys/39/5/10.1118/1.4705349
http://aip.metastore.ingenta.com/content/aapm/journal/medphys/39/5/10.1118/1.4705349

Figures

Image of FIG. 1.
FIG. 1.

An example of CUSUM status chart for μ1 = 5 mm and σ = 3 mm in the LR direction. A change in the systematic offset was detected on 18th day where C exceeds the decision interval H. The solid circles denote the offsets after being corrected with a shift magnitude of 3.6 mm calculated using Eq. (5). The corrected offsets were observed to be closer to the target value of zero than the original offsets.

Image of FIG. 2.
FIG. 2.

An example of false positive CUSUM status chart for μ1 = 5 mm and σ = 3 mm in the SI direction. A change in the systematic offset due to an unusual spike in the localization data on the sixth day where the CUSUM value exceeds the decision interval H. The chart self-corrects by indicating another systematic shift of equal magnitude on the seventh day.

Image of FIG. 3.
FIG. 3.

Percentage reduction in the frequency of localization offset exceeding action levels (Δ) range from 1 to 8 mm. For the optimal values of Δ = 5 mm and μ1 = 5 mm, the frequency of localization offsets exceeding Δ was reduced by approximately half with the incorporation of CUSUM method.

Image of FIG. 4.
FIG. 4.

Frequency of localization offsets exceeding 5 mm action level, with and without the incorporation of the CUSUM chart method, for the 18 cases with persistent shifts for μ1 = 5 mm. In majority of the cases, the use of the CUSUM chart reduced the frequency of interventions. For example, the number of interventions required for two cases was reduced from 5 interventions to 1 and from 4 interventions to 1.

Tables

Generic image for table
TABLE I.

Values of decision interval (h) for a range of σ and μ1 derived using Hawkin’s formulation (Ref. 23).

Generic image for table
TABLE II.

Percentage of charts with systematic shifts, false positives and magnitudes of shift for μ1 = 3, 5, and 7 mm.

Loading

Article metrics loading...

/content/aapm/journal/medphys/39/5/10.1118/1.4705349
2012-04-23
2014-04-17
Loading

Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Cumulative sum method in nonzero fixed action level setup correction strategy: An application of statistical process control for targeted prostate radiotherapy
http://aip.metastore.ingenta.com/content/aapm/journal/medphys/39/5/10.1118/1.4705349
10.1118/1.4705349
SEARCH_EXPAND_ITEM