**Abbreviations**

*Colorectal Cancer*

*2.7.3 Positron emission tomography PET*

dations in some aspects of rectal cancer management.

The authors declare no conflict of interest.

**Notes/Thanks/Other declarations**

**3. Conclusion**

**Figure 14.**

*PET/CT of rectal cancer.*

**Conflict of interest**

Positron emission tomography PET with computed tomography is an additional method for functional staging by imaging in the following cases: [1] in unconvincing computed tomography and magnetic resonance data for primary tumor or distant visceral metastases with elevated values of tumor markers; [2] for N-staging; 3) for M-staging. Disadvantages are the high cost and low availability of the method. Inaccuracies in the differentiation of changes in the mesorectum and pelvic lymph nodes and inaccuracies in the assessment of mucinous tumors are known. It also cannot stratify patients with complete and incomplete response (**Figure 14**).

In this chapter about rectal cancer there is content about rectal anatomy in relation to magnet-resonance imaging and TME- surgery (total mesorectal excision). There is a detailed description of imaging strategies concerning neoadjuvant and adjuvant radiotherapy and chemotherapy for rectal cancer patients. The staging and choice of treatment for rectal cancer are the main goal of any national and international organization in choosing guidelines and resp. guideline. The main guidelines are those of the European Society of Medical Oncology (ESMO), the European Rectal Cancer Consensus Conference (EURECCA-CC2) and the National Comprehensive Cancer Network (NCCN), but they also differ in their recommen-

All figures (except **Figure 6**) are provided by Teneva MD from Department of

Imaging Diagnostics, University Hospital St. Marina, Varna, Bulgaria.

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