Source of Support: None, Conflict of Interest: None
Interstitial therapy with 192Ir wires or seeds has gained considerable importance with the introduction of afterloading techniques. The interstitial afterloading techniques, the distribution of sources do not conform to that of conventional Paterson-Parker system or Quimby system. The concepts followed for specifying the reference dose rate vary from centre to centre. Analysis of some of the most popular dosimetry systems and their comparison with Paterson-Parker System of dosage are discussed in this paper.