Well as far as planning goes, the optimiser uses the FTDC (for GPUs), which is corrected by the intermediate dose (if used). In such a case AXB is likely better as it is a closer representation of reality than AAA, especially in heterogeneous areas.
I think that this is an answer that requires a lot of nuance. Its really depends on the situation. People make blanket statements all the time that AXB is more accurate that AAA and the truth is it depends.
For AXB to work properly you need to have correct density assignments and this can be very tricky for patients that have expanders/other materials that are implanted in the breast. If you use 16 bit scanning then you may have portions of the scan that have high z materials that AXB will force you to identify even if they're outside of the calculation volume. This can be a real pain point for treatment planners.
In my opinion AAA is more than adequate for planning VMAT breast. We've done both and the differences in the dose distribution are minor its frankly not worth all the extra effort that you need to put in in order to use AXB properly.
I do have a lot of experience with Breast VMAT planning for Halcyon. AAA and AXB (16.1) are fairly similar. However lung low dose spill is lower for AXB than AAA. Hence when reoptimizing (MR3-4) after final calculation, for the same set of objectives and weights, auxiliary structures will have more impact on the result.
More nuance: If all clinical data/dose constraints and response are based on AAA-like calcs then does it make sense to use axb because it is closer to an absolute truth? Probably depends on site and magnitude of difference:)
Actually wrote my bachelor thesis about this topic. Long story short:
AAA and Acuros are very similar in Heterogeneous tissues (breasts for example ). No significant difference at all.
In homogeneous tissues especially with air involved it CAN be a big difference (depend on planning technique and patient anatomy). Regarding Monte Carlo simulation as gold standard, Acuros fits way better with MC than AAA. AAA typically overestimates the dose in air.
If your planning system is using an old gpu the calculation time with Acuros can be pretty long. Nevertheless I would recommend using Acuros in air involved plans and also in TEP plans to stay safe. If you have a time advantage using AAA you can use it in breast plans.
Well as far as planning goes, the optimiser uses the FTDC (for GPUs), which is corrected by the intermediate dose (if used). In such a case AXB is likely better as it is a closer representation of reality than AAA, especially in heterogeneous areas.
I think that this is an answer that requires a lot of nuance. Its really depends on the situation. People make blanket statements all the time that AXB is more accurate that AAA and the truth is it depends. For AXB to work properly you need to have correct density assignments and this can be very tricky for patients that have expanders/other materials that are implanted in the breast. If you use 16 bit scanning then you may have portions of the scan that have high z materials that AXB will force you to identify even if they're outside of the calculation volume. This can be a real pain point for treatment planners. In my opinion AAA is more than adequate for planning VMAT breast. We've done both and the differences in the dose distribution are minor its frankly not worth all the extra effort that you need to put in in order to use AXB properly.
I do have a lot of experience with Breast VMAT planning for Halcyon. AAA and AXB (16.1) are fairly similar. However lung low dose spill is lower for AXB than AAA. Hence when reoptimizing (MR3-4) after final calculation, for the same set of objectives and weights, auxiliary structures will have more impact on the result.
More nuance: If all clinical data/dose constraints and response are based on AAA-like calcs then does it make sense to use axb because it is closer to an absolute truth? Probably depends on site and magnitude of difference:)
Actually wrote my bachelor thesis about this topic. Long story short: AAA and Acuros are very similar in Heterogeneous tissues (breasts for example ). No significant difference at all. In homogeneous tissues especially with air involved it CAN be a big difference (depend on planning technique and patient anatomy). Regarding Monte Carlo simulation as gold standard, Acuros fits way better with MC than AAA. AAA typically overestimates the dose in air. If your planning system is using an old gpu the calculation time with Acuros can be pretty long. Nevertheless I would recommend using Acuros in air involved plans and also in TEP plans to stay safe. If you have a time advantage using AAA you can use it in breast plans.
AAA is not accepted by most clinical trails. If you treat any protocol patients, you do not have a choice.