Introduction: Lymphatic mapping and sentinel node biopsy (LM/ SNB) techniques for melanoma and breast cancer management potentially expose staff, including operating theatre personnel, radiologists, pathologists and others, to ionising radiation.
Aims: To ascertain exposure levels in a practical setting and to establish safe work practices for staff involved in the LM/ SNB procedure pathway.
Methods: Cumulative intra-procedural extremity (hands) and whole body radiation doses were recorded separately for surgeons, pathologists and couriers during standard sentinel lymph node biopsy procedures from 13 melanoma and included also radiologists in 11 breast cancer cases.
Results: The measured extremity dose for melanoma procedures was zero for surgeons and pathologists. The extremity dose for breast cancer procedures was approximately 250 μSv for surgeons, and about 10 μSv for pathologists per breast procedure if done on the day of surgery, but is otherwise negligible; zero for the radiologist; and zero for the courier. No whole body dose was detectable for any staff member.
Conclusions: Using the international limit for skin dose some 200 breast cancer procedures could be performed per annum per surgeon (at the general public radiation limit) – and 2000 breast surgical procedures (at the radiation worker limit) based on extremity doses. Radiologists, pathologists and couriers received minimal or zero radiation doses from handling breast specimens. Melanoma procedures showed no measurable dose. Some recommendations for effective safe work practices are given.
Purpose: To investigate the impact of the single-isocentre technique on the volumetric dose of lung and heart for adjuvant radiation in breast cancer with regional nodal.
Methods and materials: Thirty patients treated for breast cancer with supraclavicular fossa irradiation; two techniques of treatment TMT (Traditional Matching Technique) and MIT (Mono-Isocentric Technique) are compared, TMT (tangents in SAD and supraclavicular (SCL) in SSD: Source Skin Distance) and MIT (the all fields in SAD: Source Axe Distance) (Chart 1). Techniques were compared according to dose volume histograms (DVHs) analysis in terms of PTV homogeneity and as OARs (Organs at Risk) dose and volume parameters.
Results: The dose distribution in PTV is similar in the both techniques TMT and MIT but with hot spots in the junction of the three fields for the TMT (average 120% for TMT and 110% for MIT). The analysis of DVHs shows a decrease in the mean OARs. Lung and heart dose is improved using the MIT and with significant difference in the V20 and V30 for the lung and in the V10 and V40 for the heart.
Conclusions: The results of our study demonstrated that the target volumes were sufficiently irradiated with the MIT and the lung and heart volumes irradiated were small. Furthermore, it should not be over or under dose in the supraclavicular and tangential junction.
Malignant pleural mesothelioma is a neoplasm derived from the mesothelial surfaces of the pleura. There are tree different mesothelioma types: Epithelioid Mesothelioma; Sarcomatoid; Biphasic /Mixed Mesothelioma. Patients with mesothelioma have a poor prognosis with a median survival ranging from 6 to 18 months depending on the stage of the disease at the time of diagnosis.
Standard Management: For patients with clinical stage I-III and Epithelial or Mixed histology who are considered medically fit, surgery is recommended with extrapleural pnemonectomy (EPP) or pleurectomy/decortication (P/D). Adjuvant radiation therapy is recommended for patients with good performance status: the goal of adjuvant radiotherapy is to improve local control and it is an effective palliative treatment for relief of chest pain associated with mesothelioma. Chemotherapy alone is recommended for those who are not operable, those with clinical stage IV MPM or those with sarcomatoid histology.
Radiotherapy: The target volumes delineation, defined by the radiation oncologist, is crucial because of large and irregularly shaped area at risk, high dose required for local control, the promixity of many structures as ipsilateral kidney, heart, spinal cord, esophagus, controlateral lung and the ipsilateral lung itself in inoperable cases. Actually sophisticated RT techniques such as IMRT, IGRT, and especially helical-slit IMRT (HT) might become appropriate alternatives for either definitive or palliative treatment for suitable patients based on compatible pulmonary toxicity criteria.
The actual MPM guidelines suggest that the dose of radiation should be based on the purpose of the treatment. So the dose of radiation for adjuvant therapy should be 50-54 Gy with negative margins and 54-60 Gy with microscopic-macroscopic positive margins, in 1.8-2.0 Gy/day. For prophylactic radiation to surgical sites, a total dose of 21 Gy (3 x 7 Gy) is recommended.