Luke Robertson has a metal plate in his head and a pacemaker in his chest, but that has never stopped his dream of walking to the South Pole.
In the next few days, the 30-year-old from Stonehaven will begin his solo, unassisted and unsupported journey across Antarctica in an attempt to become the first Scot - and youngest Brit - to do so.
As he made his final preparations in Chile, we found out what is going through his mind… and what is on his sledge.
Why is he doing it?
In February, 2014, Luke went to his doctor after experiencing severe headaches and problems with his vision.
The following day, he was given a CT scan but not an MRI, as Luke's pacemaker - which was fitted for a heart block a day after he finished university at the age of 23 - prevented this.
He was told he had a suspected brain tumour. It turned out he had a rare, non-cancerous, enterogenous cyst.
The surgeons operated on him for five hours. They removed a large part of the cyst, but a small section remains.
While in the Western General Hospital in Edinburgh, he met cancer sufferers and was inspired by them to finally do something he had always wanted to attempt - venture to the South Pole.
Inspired by Shackleton, Scott and Amundsen, and following his experiences in hospital and the heartache of losing his uncle to cancer, he will raise money for Marie Curie on his long walk across the ice.
His fundraising target was £25,000, but before he even sets foot on the edge of the world, he has already raised more than £31,000.
A few weeks ago, Luke visited a Marie Curie Hospice in Edinburgh and met some of the residents receiving palliative care.
"I met a softly-spoken older lady who was terminally ill," he said. "It was incredibly humbling. She listened to my story in absolute silence, then handed me £20. I was struggling to hold back the tears.
"It made all the effort, all the work that has been put into this trip so far, worthwhile.
"It will be my motivation when I am taking steps on the ice. During the hard points, those are the things that will drive me forward."
What is he taking with him?
Luke plans to drag 110kg (17 stone) of his equipment across 730 miles of snow and ice for 35 days, experiencing temperatures of -50C and winds of 100mph.
Unassisted and unsupported, he will receive no outside help such as a re-supply by air, and no support from animals or vehicles. It will just be Luke on his skiis, with everything he is taking being dragged behind him.
So what do you take on such a momentous journey? A tent, of course, along with compass, a repair kit, a medical kit, a satellite phone to check in, seven pairs of gloves, some bloomers to combat the constant head wind, and "goodie bags" of skittles, chocolate and coconut cubes to keep him going.
Every day, he will consume packets of freeze-dried food - ranging from Thai chicken to spaghetti carbonara - which he will cook on a stove.
Sir Ranulph Fiennes, who has offered support to Luke's trip as patron, is one of the Edinburgh finance worker's heroes and his autobiography, Mad, Bad and Dangerous to Know, will find a place on the sledge, along with Robert MacFarlane's The Wild Places.
Luke has downloaded hundreds of music tracks and podcasts, including Melvyn Bragg's In Our Time, from BBC Radio 4 and Radio Lab.
His fiancée Hazel and her family have also had an input. She has recorded a video message from their friends for Luke to watch while he is in the wilderness, and has made sure he has some company in the form of a fluffy penguin. A 21-year-old bottle of Springbank whisky, given by Luke's future father-in-law, is another welcome addition.
"She will be able to plan the wedding while I am away", jokes Luke. "I'm sure everything will be sorted and I can just turn up."
How has he prepared?
Luke has trained for months for the trek in Norway, Greenland and at the University of Glasgow's special "cold chamber".
In recent weeks, he has dragged tyres around Edinburgh's Blackford Hill, with some curious onlookers donating money after discovering his plans.
While on the South Pole, it is estimated Luke will consume 6,500 calories but burn off about 10,000 each day. He has had the pleasurable experience of "fattening up"'.
Luke has put on 8kg (a stone) in the past two months, and hopes to put on another 2kg in his final week in Chile by eating "three hot dogs a day with avocados and cream, burgers, and taking advantage of the buffet breakfast in the hotel".
Christmas in the Antarctica, and some fresh pants
If all goes to plan, Luke will spend Christmas Day on his own in the South Pole. A guaranteed white Christmas for sure, but how will he mark it?
"I will listen to 'Lonely This Christmas' as I tuck into my freeze-dried Thai chicken, while everyone else enjoys Christmas dinner.
"I also have a yellow Marie Curie Santa hat and some Christmas cards that I am taking with me to open."
As well as an extra special festive season on the ice, Luke has another momentous event to look forward to.
"Half way, I will get to change my underwear and my socks which will be an exciting day for me. Probably after day two, I will be looking forward to that day."
Luke is keen to make sure everyone can follow his progress on his charity trek. He flies out on Saturday to the Union Glacier camp in Antarctica, and then on to Hercules Inlet as soon as possible to begin the journey.