Dosimetry Data Requested

Please send the following dosimetry data via email at your earliest convenience to the physicist performing the site visit, or to .

I.COMPLETED FORMS(blank forms attached also available at irochouston.mdanderson.org):

Along with the IROC forms for the following items, please include copies of the indicated documents.

Instrumentation:Calibration certificates (Ion chambers & Electrometers)

Photons:Most recent yearly output calibration (various factors & calculations)

Electrons:Most recent yearly output calibration (various factors & calculations)

Brachytherapy:Source-strength certificates

II.PHOTONS:

Generate plans from your treatment planning system (TPS) for a 45cm x 45cm x 45cm water phantom. For each of the following setups, obtain MU and point-doses.

Create a copy of the excel sheet”photon beam data form.xls” for each photon beam in clinical operation. Fill out and email Tables 1-4for each photon beamto the physicist site visiting your facility or to , prior to the site visit. Please retain and submit hard copies of the plans during the site-visit.

a)PDD & Output Factors: Generate plans to fill in Table 1.

b)Wedge Transmission: Generate plans to fill in Table 2, for clinical and frequently used

wedges (eg. lower, upper, EDW, virtual, etc.). If multiple types of wedges are used clinically, then complete Table 2 for each type.

d)Profile data at dmax: Off center ratio (OCR) for the largest fieldsize and fill in Table 3.

e)Small field-size output factors (IMRT): Generate plans to fill in Table 4. For Varian machines,

useMLCs to generate these field sizes while maintaining

the secondary jaws at a 10 cm x 10 cm.

f) Small field-size output factors (SRS): For Varian machines only, generate plans to fill in Table 5.

Use the same MLC and secondary jaw settings to generate

these field sizes.

Please also have the dosimetry data book on hand for the site visit, including Wedge/Tray factors, tables of %DD, TMR & Output factors.

g)MLC and IGRT Tests: In addition to performing measurements to confirm the dosimetry data outlined above, two additional tests will be performed that will require your or another physicist at your institution assistance. The two tests are:

MLC leaf positioning test (picket fence test) – The IROC physicist will bring a script that will allow this test to be conducted fairly quickly.

IGRT isocenter coincidence test – The IROC physicist will bring an imaging cube that will have film on it. An IGRT test will be performed to verify appropriate couch shifts in an IGRT setting and agreement between kV and MV isocenters.

  1. A cube with a tungsten sphere will be placed on the treatment couch. The host physicist will then be asked to perform a series of steps:
  1. Image the cube (using whatever clinical method is common, although orthogonal kV radiographs are typically the fastest and easiest if it is reasonable to use them).
  2. Align the image to set the center of the tungsten sphere to isocenter (no reference image of this cube will exist, however, any reference image (e.g., daily QA) will usually suffice. The only requirement is that isocenter is marked on the reference image, which will allow for manual alignment).
  3. Move the couch to realise the shifts indicated in step 2.
  4. Re-image the cube
  5. Measure the distance between the center of the sphere and the imaging isocenter (as indicated on the reference image)
  6. Load a 2x2 cm MV field and irradiate the cube (performing Winston-Lutz tests)

Performance of this test is usually streamlined by the inclusion of a therapist, and this test can be performed immediately after treatment of the last patient.

  1. ELECTRONS:

For the cadre of elelctron beams,create a copy of the excel sheet “electron beam data form.xls” for each accelerator with electrons in clinical operation. Fill out and email Table 5 for each accelerator to the physicist site visiting your facility or to , prior to the site visit.

For b) through d), please have the data on hand at time of site visit.

a)Fill out table 5, providing depths for 80% and 50% dose as well as Imax.

b)Cone ratios (output factors) for nominal and extended SSDs

c)PDD (NOT ionization) for standard SSD & standard Cone Size: tabular data.

Include depth of output calib. (where clinical output is 1.000 cGy/mu)

d)Dose calculation technique for extended SSD = 110 cm

(if use VSD, please include table of VSD values)

IV.BENCHMARK CASES

The benchmark cases can be downloaded from IROC Houston’s website ( On the top bar there is a hot button labeled “on-site audits”. Under this you will find a link to the benchmark cases. There are three cases; Brain, Breast, and Cranial-Spinal. Please plan all 4 cases following the directions which are posted on the website.

Electronic address:

Mailing address:IROC Houston QA Center

UTMD Anderson Cancer Center

Attn: Dosimetry

8060 El Rio St

Houston, TX 77054

J:\everyone\Documents\Pre-visit\Dosimetry Data Request - Form -Revised 5-10-2012.doc