1. According to the ABS what was the distribution of imaging types used specifically for dose specification by all surveyed members back in 2007?

  1. Film (57%), CT(40%), MRI (3%)
  2. Film (55%), CT(43%), MRI (2%)
  3. Film (43%), CT(55%), MRI (2%)
  4. Film (52%), CT(43%), MRI (5%)
  5. Film (43%), CT(52%), MRI (5%)

Answer is #3: Film (43%), CT(55%), MRI (2%)

More than 50% were using 3D-image based planning, but of these only 2% were using MRI.

Viswanathan and Erickson, IJROBP. 2010;76:104-109.

2. For target definition, WUSM is in line w/ which GEC-ESTRO recommendation?

  1. PDW is considered the golden standard
  2. DW-ADC is considered the golden standard
  3. T2W in conjunction with PDW sequences
  4. T2W, use of complementary sequences is optional
  5. T2W images alone

Answer is #4: T2W, use of complementary sequences is optional

GEC-ESTRO WG IV considers T2W sequences as the golden standard, and the use of complementary MRI sequences optional. WUSM uses T2W-MRI in conjunction with DW-MRI.

Dimopoulos et al, Radiotherapy & Oncology. 2012;103:113-122.

3. For applicator reconstruction, GEC-ESTRO suggests CT or additional MRI sequences fused to the T2W-MRI. For which scenario would this be the most helpful?

  1. Plastic applicators on a 3.0-T MRI unit
  2. Plastic applicators on a 1.5-T MRI unit
  3. Metal applicators on a 3.0-T MRI unit
  4. Metal applicators on a 1.5-T MRI unit
  5. Plastic or metal applicators on a 0.2-T MRI

Answer is #3: Metal applicators on a 3.0-T MRI unit

Titanium applicators, while MR-compatible, can still yield artifacts in the images. These artifacts have been reported to be worse for T2W-MRI and for higher Tesla strength MRI units.

Haack et al, Radiotherapy and Oncology 2009;91:187-193.

Kim et al, IJROBP 2011;80(3):947-955.

4. Dose adaptation at WUSM is similar to that described by the Vienna group (Kirisits et al) in all of the following except?

  1. Starts with standard loading based on point A dose
  2. Modifies the loading uniformly to reduce OAR dose
  3. Aims to keep D2cc R & S<75 Gy ab3, D2cc B< 90 Gyab3
  4. Modifies individual weights to improve target coverage
  5. Calculates the EQD2 to sum with external beam dose

Answer is #4: Modifies individual weights to improve target coverage

WUSM only considers uniform scaling down of the loading to decrease OAR dose while maintaining a certain level of target coverage. Kirisits discusses symmetric as well as asymmetric loading schemes, including modification of individual dwells.

Kirisits et al, IJROBP 2005;62(3):901-911.