Andrew Howie
St George Hospital Cancer Care Centre
Senior Medical Physics Specialist

Ryan Brown
Medical Physics Registrar
St George Hospital Cancer Care Centre

Joel Poder
Medical Physics Specialist
St George Hospital Cancer Care Centre

Background and Purpose

A new Freiburg Flap (FF) was commissioned at St George Cancer Care Centre for superficial contact treatments. In an attempt to reduce the cost, existing equipment was used where possible in place of the expensive recommended equipment.

Methods

The FF was assembled and then commissioned in accordance with the American Association of Physicists in Medicine (AAPM) Task Group recommendations TG56 [1].

Testing included:

1. Stability of assembly

2. Physical dimensions

3. Phantom scan with 294mm ProGuide CT markers

4. Autoradiograph

A brief analysis of the cost savings was completed.

Results

1. Stability: The setup was stable with no slippage of catheters within the FF.

2. Physical dimensions: Compared to the manufacturer’s specifications, the buttons warped the FF slightly when pushed tight against the FF. This effect was deemed clinically insignificant in terms of source position accuracy as long as the catheter tips are reconstructed according to the internal CT markers and not the FF balls.

3. Phantom scan: The CT dataset allowed clear visualisation of the FF and CT markers.

4. Autoradiograph: The CT markers for the 294mm ProGuide needles resulted in a reference length of 288mm compared to the recommended X-ray markers at 287.5mm. Successful delivery of the treatment plan placing the source at the most distal dwell position in all channels confirmed the absence of any obstructions and confirmed that the source position matched the position of the CT marker.

By using existing equipment in place of the recommended items for the FF as outlined in Table 1, we were able to save 75% off the purchase price which equated to almost $35,000 (AUD) savings.

Recommended item Alternative item commissioned

6F Flexible Implant Tubes 5F Flexible Implant Tubes

6F Transfer Tubes 5F Transfer Tubes

X-ray markers (coded) 294mm CT markers (18 additional purchased)

Table 1: FF recommended peripheral items compared with existing equipment used

Conclusions

The FF was successfully commissioned in terms of setup and functionality. Planning techniques were established to ensure accurate treatment delivery. Cost savings of approximately 75% were achieved by using existing equipment where possible.

References

[1] Nath R, Anderson L L, Meli J A, et al Code of practice for brachytherapy physics: Report of the AAPM Radiation Therapy Committee Task Group No. 56 Med Phys 24(10) October 1997


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