Things I've Learned: Athabasca Sand Dunes, Radiation Oncology, & HI-SEAS

I'm on my second week of my radiation oncology rotation and am enjoying the learning, people, and proximity of the cancer centre to my house (a fifteen minute walk, which means I get to avoid driving in crazy traffic and 20 cm of snow). Because cancer treatment is multidisciplinary, I'm learning a little about surgery and medical oncology in addition to radiation oncology. I'm also realizing that the breadth of radiation oncology is significantly larger than I'd thought (including interesting things like ocular brachytherapy and radioimmunotherapy that I didn't even know existed). Here's a bit of information on these two things and a couple of others that I learned about this week.

1. ocular brachytherapy -- To treat intraocular tumours (usually melanomas), a plaque containing radioactive I-125 seeds may be sewn to the sclera of the eye, overlying the melanoma, and left in place for seven days.

   

   (http://www.cancer.ca/en/cancer-information/cancer-type/eye/treatment/radiation-therapy/?region=on)

2. antigen release from dying irradiated tumour cells can activate an anti-cancer immune response -- When tumour cells are irradiated and die, they release tumour antigens. These antigens are collected by antigen-presenting dendritic cells and presented to T cells within regional lymph nodes. Activated tumour-specific T cells are then mobilized to kill residual tumour cells. By a second mechanism, the irradiated tumour cells release "danger" signals (e.g. heat shock proteins) for dendritic cell activation. From Oncology (Hodge, 2008): "Radiation-treated tumour cells would thus serve as an in situ autologous tumour vaccine, initiating a strong tumour specific immune response that could irradicate residual tumour cells in primary tumours and distant micrometastases."

   

   (http://www.cancernetwork.com/oncology-journal/synergizing-radiation-therapy-and-immunotherapy-curing-incurable-cancers)

3. radioimmunotherapy -- Radiolabelled antibodies may be targeted to attach to specific markers on tumour cells (e.g. PSMA, which is upregulated in prostate tumour cells). This brings beta and gamma radiation into close contact with cancer cells to achieve cytotoxic effects in both the primary tumour and metastatic disease.

   

   (http://clincancerres.aacrjournals.org/content/19/18/4908/F1.expansion.html)

4. Athabasca Sand Dunes -- It wasn't until I saw a photo of a northern Alberta landscape that resembled the Sahara Desert that I realized our province has sand dunes. This 8 km by 1.5 km sand dune system is a dynamic landscape, slowly migrating southeast, burying forests and filling small lakes in its path. The ecosystem is home to a large number of wildlife, including Arctic terns which are not found anywhere else in the province.

   

   This part of the Athabasca Sand Dunes is actually in Saskatchewan (they straddle Alberta and Saskatchewan). (http://www.canadiangeographic.ca/travel/travel_magazine/mar09/athabasca_sand_dunes.asp)

5. kame and kettle -- This kind of landscape is common on the glacier-carved Canadian Shield. Kames are small piles of glacial debris, carried within the ice and leftover after it melts. Kettle lakes are small circular lakes, formed when water fills impressions in the ground left from large blocks of ice.

   

   (http://clasfaculty.ucdenver.edu/callen/1202/Landscapes/Glac/GlacialCont/KameKettleContext.gif)

6. HI-SEAS -- The Hawaii Space Exploration Analog and Simulation is a human habitat located on the side of Mauna Loa, intended to simulate a Mars mission. Its purpose is to research how to optimize living and functioning conditions on a potential Mars mission. The HI-SEAS 1 mission (2013) involved six scientists living in the habitat for 120 days. The scientists conducted research and, in keeping with the simulation, ate freeze-dried food and wore spacesuits whenever they ventured outside. The HI-SEAS 2 mission (2014) involved further research with six scientists (including one from Edmonton) over 120 days. The HI-SEAS 3 mission is presently underway.

What is something you learned this week?