MATH RESOLUTIONS / Document #:
WI 12.3 / Rev.:
00
Title:
Points Resolution Work Sheet. / Effective Date
6 June 2011 / Page #:
1 of 4

ApprovedBy:

/

Wendel D. Renner

President / Signature / Date

REVISION HISTORY

Revision / DCR # / Author / Description of Change / Effective Date
00 / 119 / W. D. Renner / Initial Release / 6 June 2011

Purpose:

To work toward a resolution if the point test has failed.

To be determined:

Does the customer’s treatment planning system agree with the customer’s beam data?

Is the correct rmu value found for the field size?

Does the beam data Dosimetry Check is using agree with the customer’s data?

Is the correct definition of the monitor unit being used by DC and the treatment planning system?

Method:

Fill out data below as may be needed. Alternately use an Excel spread sheet.

Machine name: Energy:

Field size:

RMU value: Plan mu value:

For field size other then the calibration field size, the in air scatter collimator factor (look up from DC beam data file):

The Plan mu times the in air scatter collimator factor:

Calibration Condition - field size: SSD: Depth:

Calibration Condition Dose Rate in cGy/mu:

Note: if percent depth dose must be converted to a different SSD, match field sizes at depth.

Percent depth dose value:

Inverse square law factor (example: if calibration condition is not 100 cm to the chamber, i.e. typically: [100/(100+ dmax depth)] 2 )

Calculation of the expected dose at a point:

Depth cm / DC Dose cGy / Plan Dose cGy / difference
Dmax:
5
10
15
20
30
40

If differences change significantly with depth:

Depth cm / Customer’s % depth dose table value / % depth dose from DC machine used / difference
Dmax:
5
10
15
20
30
40

If there are significant differences

Depth cm / Plan Dose expected from Tables / Plan Dose / difference
Dmax
5
10
15
20
30
40
Depth cm / Plan Dose expected from Tables / DC Dose / difference
Dmax
5
10
15
20
30
40