Cost analysis and estimated radiation exposure
Table 4 gives an estimation of the costs incurred by performing
both PL and SPECT/CT. The cost per procedure of
PL is £119. The cost per procedure for combined lymphoscintigraphy
and SPECT/CT is £282. According to our local
radiology department, the effective dose of radiation sustained
by the patient during PL is approximately 0.5 mSv.
The addition of a low-dose CT for hybrid SPECT/CT imaging
results in an additional effective dose of up to 2 mSv.
Discussion
PL not only provides a method of accurately identifying
SLNs on a direct drainage pathway from the site of the
primary melanoma, but can also highlight those nodes
draining through unpredictable pathways. Common to most
nuclear medicine imaging however, anatomical detail is
lacking. The introduction of hybrid SPECT/CT has provided
a solution to this problem.
Several recent studies looking into the application of
SPECT/CT for LM in melanoma have reported the detection
of additional SLNs not identified by planar imaging. Veenstra
et al. showed that SPECT/CT isolated additional SLN in
20% of patients. In 5.7% of patients in this study, the
additional nodes resided in a separate nodal basin. SPECT/
CT provided additional anatomical information in 31%
of patients and surgical approach was altered in 29%.1 In a
similar study, Van der Ploeg et al. identified additional
SLNs in 8% of patients and 30% of those nodes contained